So after perusing the comments section, a few engineers, including Hambini and PeakTorque, mentioned that the broken axles I demonstrated could be due to a shear failure (due to torsional overload), potentially amplified by internal defects within the aluminium. This theory could well hold up, as the broken axles were not particularly old, so aluminium fatigue is unlikely to be the only suspect, and the QC on some of these cheaper parts is definitely a little questionable. Anyway, appreciate all the comments on this one, every day is a school day folks!
To explain my reasoning, aluminium is a ductile material so you typically get a ductile fracture. The stress on the crank is predominantly torsion, the bending stress is not that high through the crank axle because it's supported by the bearings. If you assume the bending stress is very small (you essentially ignore it) and then look at the torsional loads. Typically in engineering, you would refer to solid shafts for reference so the fact this axle is hollow makes the analysis a bit more tricky. HOwever, the failure mode exhibits similar characteristics, the most noticeable one is the failure occurs at an angle and there appears to be some slight necking. I would emphasise the caveats associated with the statements written and that being it has not been visually inspected - going off a photograph is not conclusive.
From the images, it looks like fatigue failure (i.e. very slow crack growth over many months probably from a manufacturing fault or flaw). Fatigue crack growth can occur under shear or torsion. Two thirds of the surface in the image is smooth indicating fatigue crack growth. I can't see it in the photo, but the smooth surface should have very small close together parallel lines (a bit like a nail file). Each line represents the fatigue damage from one cycle of the crank arm. The remaining third of the cross-section of the shaft is very rough. This is caused by sudden and final plastic collapse failure which occurred over perhaps a dozen cycles. This due to the torsion loading of what remains of the cross section and is what Hambini is referring to. Any Aluminium component under such large stress cycles is a statistical ticking fatigue time bomb (i.e. will your crank could last 10,000 km or 100,000 km. It will fail sooner or later. Steel at the same stress will be 100,000 - 1 million km. Increasing the diameter and thickness of the shaft helps a lot. But if I were to spec a bike to ride around the world on (i.e. Jenny Graham and Mark Beaumont), I definitely wouldn't go with any Aluminium shaft. Remember that the Tour De France Pro's throw their near new chainset in the bin at the end of each year. If you were to sell on the bike, the new buyer won't know what they are getting with Aluminium. The best bet is to take the weight penalty of steel.
Someone pointed out what looks like a crack on the spindle at around 11:34 of the video. Can someone confirm whether thats a scratch or potential crack?
@@davidgarza2267 So i had a look last night, fortunately it's not a crack, just a scratch in the Aluminium. Its also not super deep either, but ill keep an eye on it either way!
That is dedication to your viewers, risking a broken axle, torn open flesh, a horrific road accident, being fed on by zombies and the calamitous end of the world, just to prove that Aluminium is fine for a crank axle! Good work as always, keep it up because your videos are always lovely and fun. 😁
@@TraceVelo Once I was launched over the bars and broke a thumb from a crankset breaking...................my thumb will never be right again....all from riding questionable parts..
@@bradsanders6954 It's always a shame when something breaks, and it's twice as bad when ppl are injured (like you). But fatigue can happen everywhere. Last year the splines on my Ultegra-set broke on the left crank. Also last year on another bike with FSA-crankset the chainring broke. Which brings me to my conclusion: if Ultegra or FSA can fail, then so can Chinese parts (at a third of the price)
@@klcbsoft I tend to think,and to hope,that a big company like Shimano does more testing than a no name cheapo chinese product....my crankarm broke as it was cracked and I didnt catch it before it broke....it was an old Gipiemme.....inspect and clean all parts and who knows what you might find?
Hambini keeping me on my toes! I think you might be right here, so I’ve pinned a comment to this effect. Anyway, thanks for the comment dude, always good to be challenged on this stuff!
Engineer here: Those machining marks in the middlesection kind of worried me back in the originial video about that crankset and now my worries are proven right by the mode of failure shown. The rough machining results in troughs and spikes in the surface, similar to a threaded rod, just not that deep. But it is apparantly enough to cause stress spikes in those throughs that go right around the part. Just a recipe for cracks forming and finally failure in the part. Hence shimano HTII axles are smoothed in the middlepart. If they maybe sandblasted the surface or went over it with a finer feed rate at the machine those axles would be way more reliable. Also the axles shown for SRAM are smooth and plated all around.
Thanks so much for the comment, really insightful! I think you might be onto something actually. Looking at the photos between the 2 failures, they both broke at prety much the same point too... Ill def keep this comment in mind when reviewing cranksets in the future!!!
@@TraceVelo I've got the exact same crankset, the axle is aluminium as well, but the axle has been anodized black. Would that prevent the fatigue issue then?
That might be the case too. However, I think the main reason the aluminium crank snapped at the same spot because of the nature of aluminium itself which is much softer than steel. In other hand, when I was doing a research on lubrication application on aluminium rod using pin on disc machine, I found that different type of lubrication also plays important role in reducing friction especially at those wear marks. When I looked the wear marks under SEM machine, the crack propagation is much wider on unlubed aluminium rod compared to aluminium rod that were lubed with conventional lubes.
@@ruudboek Whilst anodizing is a form of layer or case hardening (can be 3x harder than the raw material) it won't stop fatigue. It will put it off for longer, but by how much? How long is a piece of string? It kind of depends on where and why these failures are happening. Is it from the outer diameter under tension failing, or the inside diameter under compression when the spindle flexes under load? It is an improvement regardless to material rigidity. Compared to an identical piece of material that is untreated (and barring imperfections) it should last longer. Note: The harder you make something, the more brittle it also becomes. It can be a bit of a trade off. For a constant given load, lets say a motor running a generator and the driveshaft is aluminium, with anodizing that shaft could be a lighter item from less material lasting just as long as an untreaded AL shaft. BUT that's for a constant loading through that shaft (the drag from the generator unit), our pedalling on flats, up hills, away from standstills isn't a constant, it's always variable loading. A very slight possibility of anodizing also being detrimental though if the inner diameter is also anodized. As you pedal and the spindle flexes, the inner diameter compresses whilst the outer stretches, ever so slightly but still happens, hardening those layers will make for a stiffer axle... for a while, then long term fatigue will catch up at some point. An essence of stretch and elasticity are good properties for longevity, not something aluminium is very good at.
@@two-eyedRoy from the pictures of the failures at 8:20 I would say that it looks like the crack formed on the outside where the alloy yielded under the stretching induced by the torque of pedalling, benefitted by the surface finish. I come to this conclusion because the outer edge is very clean, almost 90 degrees into the material with crystaline looking surfaces which is typical for strain hardening in aluminium, while the inner edge looks more fuzzy and broken out like the material was twisted apart. I know that I might succumb to my conformation bias right here but I strongly think that the outer surface gave way first.
Great vid as usual Luke! :) I can see the failure point in your crank spindle. 11:34 - 11:36 as it rotates through the light you can see a hairline crack including a couple of pits in keypad 8 (break the screen into 9 [3 rows, 3 columns, 8 is the bottom middle square]). Can't say when it'll go, but when it does I'd put money on that area being it. I doubt changing the machining (from that fast rough cut that's almost a thread to something smoother that takes longer) would make any difference as that hairline looks to have been present during machining (evidence being the little facets either side of the crack that glint in the light) That does also imply the the bar stock was not forged and possibly not extruded either (could be wrong on the latter, not entirely sure). Like the '80s Castrol ad. 'Oils ain't Oils', metals are no different. AL 7075 cast is rather inferior (crystaline structure) to extruded 7075 (crystaline structure uniformity) and then forged 7075 is slightly better again (crystaline structure uniformity under compression). Those three states are also increasing in cost to purchase. A note on advertising jargon: A 'billet' is just a single piece or chunk of material. It doesn't define any level of quality. A billet of junk material, is still junk. It's a fad term from the car wheel industry that since got picked up by motorsports and now any manufacturer wanting to hype up a product now faps into their own face about billet this/that in their advertising. The term/phrase you want to read/hear is 'Billet Forging', because the Forging gives the material it's best structural properties.
@TraceVelo : Smoother surface will increase the resistance towards fatique. The 'lines' of milling will increase the chance of tear or rupture. Smoothing it with sanding paper will increase the durability in regard of fatique. The initiation of the cracks are on the surface, smoothing it will decrease that initiation of a crack.
Luke maybe you won't read that but i want to let you know i'm an avid (and subscribed!) viewer from Spain that really enjoys your vids. I value inmensely your honesty and dedication to this sector of cheap bike stuff. I own a cheap mtb kinda converted for road use but i plan to build myself a proper disc brake road bike this year using a frame and parts reviewed in your videos. Just wanted to let you know you have active viewers from all around the world that find tremendous value in your work. Take care mate, and keep doing this forever please :D
Hi Luke! Just wanna share my experience here on this exact crankset too! I had 2 of this exact cranks in 165mm. Both had the same problems where the GXP mounting surface on the crank is slanted/offset, such that my chainring doesn't spin in a straight-line. It cause my chain to rub both sides of my FD even in 50-11 gear. For the #1 purchase, I told the seller about the issue where my chainring doesn't spin straight. The seller kindly told me that the chainrings are CNC-ed to a good tolerance, and it must be the cranks that have issue. With little questions asked, the seller sent me a new crank, and the problem is solved. For my #2 purchase, the slant/offset seems even worse. Worse part is no reply from seller yet. So kinda hit or miss
Wow interesting. Maybe in your case, the parts were damaged/bent during shipping, which led to the issue. The packaging on some of this gear is a little hap-hazard for a 3 week shipping period from China... Thanks for the comment tho, always good to hear other peoples experiences!
I had a ZRACE Hardrock MTB crank where the left side arm was held only by a single aluminium bolt that goes into the center of the crank. Unlike Shimano it had no pinch bolts, and kinda looks like a GXP setup. After almost a year of use, the bolt snapped it's head. A similar crank to this is the Fovno Ghost. I now went for a Prowheel MPX-11 crankset where the left crank arm has pinch bolts Similar to Shimano Hollowtech. It's a bit heavier but it looks like it will last longer.
I had the same problem here. They sent me new rings hoping it would solve the problem but was the same. Turned out the axle wasn`t bonded in straight with the arm. They where kind enough to send a new arm out also and this one has been fine.
Shimano HAS used aluminum axle! 12 years on my Shimano DEORE LX crankset,and those are still running! The stiffest cranks that I ever used! Excellent cranks! Greetings from Croatia 😊
Those carbon fibre caliper brakes are spongy, totally NOT stiff. Only good for the rear wheel as ABS caliper brake. The whole thing flexes. VERY light indeed!
I was wondering when you would make an update on this crankset and it finally came! This is why I always consult your channel in regards to these chinese parts. I have the same crankset and it feels so great to ride! The bottom bracket was kinda iffy tho so I got that replaced quickly but seeing how much punishment yours was able to take just gives me peace of mind that I'll be able to ride my bike without worrying about my crankset. Awesome stuff as always Luke!
1) You can go cheap, little heavy & safe. 2) Cheap, lite & not safe (then why manufacture the product?) Probably stupid engineering and less ethic. 3) Reasonable price, lite & safe (probably shimano tiagra 105). 4) Expensive, lite & not safe (ultegra & duraace). Evil Shimano, the vampire blood sucker.
I worked at a bikeshop in highschool. There was a old man who rode his bike 365 days everywhere and its a was a old alu raleigh frame for commuting and he told us that when he was making a turn down a hill he felt the crankset area loose and he couldnt transfer power. As it turns out the frame gave at the bb area due to fatigue and only the top welds where holding it. Nothing bad happened since he has braked already. That was a cool experience.
Luke mate, we respect the graft, don't be apologetic about the subscribe&like/sponsor slots. Far more interested in Siroko than the 5 property investment videos I have to sit through before starting the vid
Hi there. 5:30 Your right knee reaches more under the handlebar then you left, from top view, as if you have 175 mm crank on you right and 170mm crank on you left. 8:20 Fotage reveals cranks break toward the non-drive side sugesting the load was applyed on the left crank uppon breaking. To hinder axle break, try applying a pull on the drive side while applying pressure on the left crank. That is, help your left crank spread the load buy pulling simultaneously on the right crank, ballance the load with opposite load.
Getting 7000 miles out of chain rings that cost $34 to replace is outstanding. Full stop. Are there really people who think parts should last 70,000 miles? I'm doubtful that 99.9% of the cycling community will ride 70,000 miles in their entire lives. In my observation, almost everyone replaces bike parts to get the newest thing, or other vanity based reasons, not because they actually wore it out. I bought that crankset (chainset) based on your video, put a few thousand miles on it on a road bike, then converted it to 1X and I'm using it on a gravel bike now, beating the hell out of it. So far, it still looks new.
@@CrabgrassFarmer Got news for you. Most FSA is basic aluminum stuff. Nothing wrong with it but nothing special either. Besides, this is not an inner single chainring. It is inner and outer machined from a single billet of aluminum, one piece. Requires considerably more material and work to make it. Far stiffer and lighter than the typical two chainrings held on with 8-10 bolts configuration that most cranks use.
@@elephantcup I stand corrected. Thanks. I realized sometime after I posted that this was a one-piece crankset and didn't get my comment deleted timely.
Great video, interesting to see a crank failure from trace and a Dura ace crank failure vid by Hambini on the same day! It seems the cheap ones no worse than the most expensive…
I think apart from the smaller diameter of 24mm (compared to DUB at 29 or BB30 at 30mm) the material on this crank is of inferior quality, despite supposedly being made of the same 7075 aluminium as more expensive cranks. It looks like it's cast instead of forged. Which would explain why the grain structure won't be able to cope with loads as reliably. It would also explain why it is that cheap bc it's obviously cheaper to produce. Getting the steel axle version is probably a better idea. The manufacturer seems to agree.
Another excellent video Luke. Both educational and entertaining. Kudos for making these whilst holding down a day job. I am still putting off editing my own GoPro videos from last year! May your subs continue to roll in and the sponsors keep sponsoring 🙏🏼
Luke you should try our the EE Brakes that are on AliExpress for sale. I picked up two pairs and love them. The ZTTO brakes that you've picked up are really light but are extremely narrow (rim width has to be less than 24mm). Some people who bought them say they are based on the old Ciamillo Lekki8 brakes? Would be great for you to confirm that info in your review.
I've got a cheap IXF 1x crank on a 29er hardtail I have.....Been on there 3 years and doesn't appear to be crap as yet....I haven't a clue whether it's an aluminium axle or steel as I just fitted it when I got it.....It runs well with a SRAM GX setup.... I even stuck one on an old 26er hardtail last year (1x11 conversion), when I couldn't get hold of a Shimano kinda thing, and it's been pretty damn good.....It also runs very well with a SRAM NX setup..... I do check my chains regularly with a chain checker and just replace parts when necessary.....On a 1x chairing, it's just a piece of piss to stick another one on....Just keep your bike clean is the best advice.... Saying that, I don't really put much load on the pedals as I'm pretty ancient and only weigh 9.25 stones and it's pretty flat around here in Peterborough UK.. Good video again fella.
I'm running a cheap Chinese crankset on my bike as well, though not this exact one - mine is made by Litepro and I use a 1x drivetrain. But your video made me check the specs and I'm certainly happy to see that the axle on mine appears to be steel, so I don't need to worry (although I'm not a masher by any means, especially as there are basically no hills to speak of here in Shanghai).
Good good I'm happy I've got 3000 miles with bugger all wear out of my Cannondale Spiderring, but as a mountain biker in the Pennines 1000 miles out of a chainring is a miracle!!!!
Repeat again what Luke said - because of the failure mode aluminium it's hard to be sure that the crank I have is fine, but so far so good. That caveat out the way, I got a Zrace DUB crankset as part of my Sensah "groupset". This is a fairly standard 5 point spider bolted onto the cranks (same SRAM style as Luke's) with individual aluminium rings bolted on to a spider. I was getting a lot of BB creak which after a lot of messing about I realised was not the BB at all but the bolts on the spider. No matter what I tried the creaking always came back so I got the "Zrace Hardrock" one piece replacement - ie both chainrings and the spider machined out of one piece of aluminium. This comibination so far is really good - done 1000+m on it. Also it's much easier changing / replacing chainrings this way than the traditional 5 point spider - just 3 torx screws attach the one piece chainring to the cranks so it's quick and easy to swap. I'm a heavier rider (98kg) but I don't notice any flex in the crankarms and the Hardrock chainrings are showing little wear. Hopefully because it's DUB axle it is less prone to this sort of failure but who knows.
I have a cheap IFX crankset in the box, to be installed tomorrow. And I just checked it w/ a magnet, and they were attracted to each other. Kind of like cheap love.
UsefulMuffinCat is right. Those machining marks are definite stress raisers and will contribute to fatigue failure. Most engineering texts counsel against this kind of finish. I've had other components like seat post saddle clamps fail from similar poor design. On fatigue failure, it is not unpredictable. Typically, fatigue cracks will be evident and growing for some time, until there is not enough material cross-section left to maintain structural integrity under load and then the rest of the structure has its strength exceeded and it fails in shear. You can see this by examining the surface of the failure. Where the face is shiny, that is from sides of the growing fatigue crack rubbing each other smooth as the component flexes under load. The rough surfaces are where the rest of the material finalyy failed in shear. This is evident in a couple of the shots on your video. I have serious doubts about those rings and axle being 7075-T6 at that price point. The average punter will not be able to know whether he is getting dudded or not. The vendor is likely using something cheap and easy to machine, confident he will never be caught. 7075-T6 is challenging to machine and requires expensive cutting tips. Hand tools hardly touch it and drilling it requires brand-new sharp bits, or your drill bit wanders all over the place. To resolve some chain snatch issues from poor tolerances on a similarly priced MTB chainring, I found the tooth thickness was easily modified with an old file. No way they are 7075-T6 as claimed. Does this help? I enjoy your videos and watching you progress and mature your presentation style. Keep it up.
You're correct... aluminum will fail, given enough loading events. Plus, while steel is ductile, and will elongate and stretch prior to failure, giving you some heads up that it's going to completely fail within time (hopefully enough heads up to notice before full failure). Aluminum, however, is a very brittle (the opposite of ductile) material in failure. So aluminum DOESN'T give you much of a heads up... so, you got that to worry about now.
Steel fails in a bunch of different ways (including fatigue if there is a stress concentration or high loading). Not all of them are ductile failures, depending on geometry and the specific type of steel used.
Thanks for the heads-up; I just ordered the steel axle version of the crankset. I'm a heavier rider and I really appreciate the follow-up on your videos. When it's all said and done I probably haven't saved much money over Shimano (new steel axle crankset was $31, $20 shippng) but I like the look of these better, setup was easy, and shifting is no issue. And the faux-speedplay pedals are still going strong - that was a great purchase!
hoop strength is something most people will never have to deal with most car drive shafts that put power down have a aluminium shaft somewhere on it so a small bump in diameter has a huge improvement on strength like 4x
A very long time ago bikers had a trick as a life insurance. They put a wooden pin in the fork tube. Maybe you could do the same thing with the crank axle to be on a safer side.
Yet another excellent video, glad to see you're settling into your new pad. Would be interesting to see what some non destructive testing would reveal on your crank. Would make a really nerdy metallurgy video. Keep them coming.
Just got my 165mm Senicx (BSA68) to try out shorter crank arms on my tri-bike. Comes with pre-load adjuster. Smooth finish on axle. So far, worx well enough.
Great video. When I did my build last year I used the same crankset (I also used the same 'Speedplay' pedals). I'm a heavier rider so I'm going to replace it with the steel axle version. Your updates are much appreciated.
Great Video! I had the exact same problem on the exact same cranks. Axel snapped as i was pushing off from a red light. I'm 6'2", 210lbs and had about 4500mi on the cranks. Company replaced with the steel axel version under warranty and so far ok. I will give it one more year and if there are any more shenanigans, I may just spend the $$$ to go Shimano or explore the larger DUB tech as you suggested. Thanks again!
There's another issue you didn't mention. The crank arms are dead straight. Other brands make them slightly curved outwards to give space to the shoe of the rider. The CVR cranks were unusable for me. I had to put spacers on my pedals to avoid the shoe touching the crank every revolution. I don't recommend these cranks for this reason.
Having just watched Hambini's DA crankset and now your super Ali one (and all your other videos), I maintain that Shimano 105 11 spd rim brake is the Goldilocks groupset. Shimano, if you're listening, leave it alone!!!!!!!
There was at least one generation of Shimano road cranksets having aluminium axles - in particular, the 105 FC-5600 ones. I did have one and it did have an aluminium 24 mm axles, but with somewhat thicker walls. It was one of the first generations of Hollowtech II axles I think and the crankset weight as near as makes no difference the same as the next generation of 105 (FC-5700), which came with steel axles. There were some reported cases of Shimano aluminium snapped axles, but then again there are just about as many featuring steel Hollowtech II axles. I guess there are other factor in play there, such as the parallelism of the bottom bracket bearings or preload force.
Can't be too bad if you're sticking with it for the time being, thanks for the entertaining and informative content, looking forward for more. I especially like the budget bit. I had my bike nicked; a felt 2014 mountain bike £475. Went to cash generator and found amongst the others a boardman 8.6 mtx, it was scruffy it was stuck on the middle crank out of 3x and tektro hydraulic brake, 700c. Because I've been riding in middle crank for 12 weeks I'm thinking I don't need 3 up front just a single 9x, then you're content popped up and it's energised me to shave off the weight even more, the boardman cost me 300, new in the shop 575. So it's kind of screaming out up grade me, I'm starting with the front crank then elite wheels then a 1000w electric motor! Just joking
I ordered the Goldix RX crank arms (the ones that look like ROTOR) in 165 when the turned up they where basically these crankarms but without the CVR/Hardrock logo so I checked the listing and they don't do a 165 in the "ROTOR" style (my fault for not paying attention basically) so I suspect Goldix/CVR/Hardrock/Zrace etc. all pee from the same pot. Cranks have been great to be honest they have the steel spindle and I have put them on my road and gravel bikes. I don't do much road but 12000+ km on the gravel and so far no issues. Although I don't use their chainrings as both my bikes are 1x.
Nice, thanks for the comment Chris, always good to hear some other experiences with these parts! I think having a steel axle will really help with the longevity of your crankset!
To check whether yours is aluminium or steel, just put a magnet on the open end of the metal shaft on the drive side - which can be seen at the start of Luke's vid.
Just about every BB30 crank has used an aluminum axle since Cannondale invented the standard two decades ago. The problem isn't that fatigue curve per se, it's something in the uniformity of the metal or the manufacturing that's changing the slope.
Yesterday I was watching Hambini's video about Ultegra and Dura ace crankset problems. Today is yours. I'll start to wonder if I can put a sail on my frame
Great video as always Luke! Your videos are the ones me and my mates look forward to. Esp for budget options. Your coverage and review and update on the ltwoo and sensah groupset helped us allot on the decision. Thanks for all your hard work luke truly
Do you ever buy any cycling gear from your LBS? Shimano did use aluminum (24mm) in some of their earlier generic & 6600 series compact cranks. Major brands (Shimano ,SRAM & Campagnolo) although cost more I am convinced that they perform better and a better value. My shop is totally independent (no contacts to anybody & sell many major brands other than Giant , Trek , Cannondale & Specialized) and I have been working on bicycles for 50 yrs so I come with a little knowledge. Thank you for looking into the various component brands out there. I think you will find that the Chinese made parts will work OK ( everybody's idea of OK is different) but will not last as long as the original designed part (ie. the Cannondale copy chainrings). We live and hopefully learn everyday. Keep up the good work.
Are aluminum axles unusual? Our wheels are running on aluminum axles. Also, some mountain bike cranks use aluminum spindles. Those have to take the load of landing jumps crooked, casing landings, and high speed rock strikes while standing on the pedals. All fine. With that said, I’m not sure large aluminum spindles are preferable. Smaller diameter allows for larger, more durable bearings.
Chainrings, like cassettes, will wear and may need to be replaced after about every 3 chain changes (providing the chains are not over-stretched before replacement as your cheap chain was). The problem isn't so much that the teeth become prone to breaking because they are thinner, it is that they wear on the contact edges and when you put on a new chain it only engages with the first one or two teeth on the chainring thus putting all of the force on those few teeth. This is exactly the situation that you showed at 2:52 in your clip.
I'm tempted to say the crank you showed hasn't failed because of high cycle fatigue, the theory you presented. I'm fairly confident posting this comment because of the very limited use that crank had and the extensive portion of brittle fracture shown on the broken surface, while the typical surface associated with 'beach marks' (high cycle fatigue propagation marks) cannot be clearly observed. I'd say the axle failed because of crack instability after a very limited number of deformation cycles (Linear Elsatic Fracture Mechanics, LEFM) from a pre-existant defect, likely way bigger than the tool marks you pointed. Moreover, I wouldn't be surprised if the original defect was on the inside of the crank: the outer surface is easy to inspect and I presume (hope...) Chinese manufacturers do visual quality checks on their products, while an inspection on the inside is way more expensive and time-consuming, but this is just speculation since I'm already saying waaaay too much from such a picture. The fact that 7075 T6 Al has very low fracture toughness doesn't help at all. An overload as you described may have caused this type of fracture, wich is fairly common on high perfomance aged Alluminium alloys. But the basics you reported are true, the surface of the crank is indeed not polished but 'roughly' finished by tool (looks Ra 3.2), which does not help with fatigue life, no matter if high cycle or low cycle. The standard of the industry for axles is a smoothed surface blasted with high energy media in order to induce compressive strain on the surface, improving fatigue life and closing non-visible defects. Great video anyway.
Yeah I've been fiming that episode today. Still have a lot more to shoot, and obviously all of the edit to do, but I should have it up by the end of the month!
My OEM 3x lasted over 6 years 50k miles give or take when it did wear out I had to get a cheap 1x off Amazon good thing the shop I used had no trouble getting it setup after 3 bottom bracket that is
Great video,I see the ZRACE Rx road crank has a 28.99mm like Srams which is great to see. Thanks for the info and what to look out for, I really appreciate it.
Aluminium chain rings don't necessarily mean a short service life, I'm still using my original 1985 suntour cyclone and Shimano 6200 cranks and rings and there's no issues.....Probably because the Japanese cared about their customers back then....unlike now where they just want your money....glued together dura-ace anybody??
I sheared a Cdale SI crankarm right off the spindle a couple years ago, and had replaced the crankarm bolts because they tended to strip easily, for me.
Great content! The Shimano's crankset Tiagra FC 4650 has 815g, with a steel axel... Minimaze the height is cool but interesting value the risk... 🤘🏻🤘🏻🤘🏻🤘🏻🤘🏻
Shimano did make an aluminum hollow tech spindle for one year but abandoned it for the hardness of steel. The spindles are all forged, and at 24mm your not paying a big weight price for the stiffness and hardness you need.
About the 'all carbon fiber' calipers, i've had 2 sets, first one was too narrow for my 26mm width winspace rims, other set was ok, i had to add an elastic on the caliper to help it get back to its open position, and there's a lot of flex in it when braking, so i can't wait to see what you have to say about these 🤙
Back in the Stone Age (well,1970’s) during my Road Racing days I broke 2 Campag Record cranks ..above pedal thread. Early 2000’s had 3 FSA Carbon Crank fails when pedal thread insert became unbonded...Seen an awful lot of Shimano Road Cranks fail in the last while..so? Would say from my experience of riding Chinese Carbon frames from Ali Express for the past 10 years that the old argument of rubbishing these products ( often promoted by Mainstream,Overpriced Bike Brands,also made in China) is mostly inaccurate! Those cranksets you feature ,if branded by a company beginning with s and ending with m...would cost about £350! Prob would choose Steel 24mm axle though.
Bought these cranks because I was in need of new cranks in the summer of last year and you recommended them and well...they fit my budget. Since I saw this video I was a little worried so I took my cranks off my bike and checked the axle and it looks good. But it kinda looks like steel to me. So I took a magnet and my axle is 100% magnetic. I googled 7075 and it is basically alloy with zinc neither of these materials is magnetic. So am i right assuming my crank is actually a "newer" model and made of steel?
So after perusing the comments section, a few engineers, including Hambini and PeakTorque, mentioned that the broken axles I demonstrated could be due to a shear failure (due to torsional overload), potentially amplified by internal defects within the aluminium. This theory could well hold up, as the broken axles were not particularly old, so aluminium fatigue is unlikely to be the only suspect, and the QC on some of these cheaper parts is definitely a little questionable. Anyway, appreciate all the comments on this one, every day is a school day folks!
To explain my reasoning, aluminium is a ductile material so you typically get a ductile fracture. The stress on the crank is predominantly torsion, the bending stress is not that high through the crank axle because it's supported by the bearings. If you assume the bending stress is very small (you essentially ignore it) and then look at the torsional loads. Typically in engineering, you would refer to solid shafts for reference so the fact this axle is hollow makes the analysis a bit more tricky. HOwever, the failure mode exhibits similar characteristics, the most noticeable one is the failure occurs at an angle and there appears to be some slight necking. I would emphasise the caveats associated with the statements written and that being it has not been visually inspected - going off a photograph is not conclusive.
@@Hambini did your hairdresser write this for you ?😄
From the images, it looks like fatigue failure (i.e. very slow crack growth over many months probably from a manufacturing fault or flaw). Fatigue crack growth can occur under shear or torsion.
Two thirds of the surface in the image is smooth indicating fatigue crack growth. I can't see it in the photo, but the smooth surface should have very small close together parallel lines (a bit like a nail file). Each line represents the fatigue damage from one cycle of the crank arm.
The remaining third of the cross-section of the shaft is very rough. This is caused by sudden and final plastic collapse failure which occurred over perhaps a dozen cycles. This due to the torsion loading of what remains of the cross section and is what Hambini is referring to.
Any Aluminium component under such large stress cycles is a statistical ticking fatigue time bomb (i.e. will your crank could last 10,000 km or 100,000 km. It will fail sooner or later. Steel at the same stress will be 100,000 - 1 million km.
Increasing the diameter and thickness of the shaft helps a lot. But if I were to spec a bike to ride around the world on (i.e. Jenny Graham and Mark Beaumont), I definitely wouldn't go with any Aluminium shaft. Remember that the Tour De France Pro's throw their near new chainset in the bin at the end of each year. If you were to sell on the bike, the new buyer won't know what they are getting with Aluminium. The best bet is to take the weight penalty of steel.
Someone pointed out what looks like a crack on the spindle at around 11:34 of the video. Can someone confirm whether thats a scratch or potential crack?
@@davidgarza2267 So i had a look last night, fortunately it's not a crack, just a scratch in the Aluminium. Its also not super deep either, but ill keep an eye on it either way!
That is dedication to your viewers, risking a broken axle, torn open flesh, a horrific road accident, being fed on by zombies and the calamitous end of the world, just to prove that Aluminium is fine for a crank axle! Good work as always, keep it up because your videos are always lovely and fun. 😁
Thanks Jayne! Yeah maybe it's foolish, but I LOVE testing out new gear and pushing the limits a bit, time will tell if these fail on me :S
@@TraceVelo Once I was launched over the bars and broke a thumb from a crankset breaking...................my thumb will never be right again....all from riding questionable parts..
@@bradsanders6954 It's always a shame when something breaks, and it's twice as bad when ppl are injured (like you). But fatigue can happen everywhere. Last year the splines on my Ultegra-set broke on the left crank. Also last year on another bike with FSA-crankset the chainring broke. Which brings me to my conclusion: if Ultegra or FSA can fail, then so can Chinese parts (at a third of the price)
@@klcbsoft I tend to think,and to hope,that a big company like Shimano does more testing than a no name cheapo chinese product....my crankarm broke as it was cracked and I didnt catch it before it broke....it was an old Gipiemme.....inspect and clean all parts and who knows what you might find?
Those failures don't look like metal fatigue they look like torsional overload or shear overload.
Hambini keeping me on my toes! I think you might be right here, so I’ve pinned a comment to this effect. Anyway, thanks for the comment dude, always good to be challenged on this stuff!
@@TraceVelo I'll reply to your pinned comment.
Like a five year old to point out the obvious! :-) :-)
Or it's possibly from bearing deformation from contact between parts.
Marketing fabrications to spread fear?
Engineer here: Those machining marks in the middlesection kind of worried me back in the originial video about that crankset and now my worries are proven right by the mode of failure shown. The rough machining results in troughs and spikes in the surface, similar to a threaded rod, just not that deep. But it is apparantly enough to cause stress spikes in those throughs that go right around the part. Just a recipe for cracks forming and finally failure in the part. Hence shimano HTII axles are smoothed in the middlepart. If they maybe sandblasted the surface or went over it with a finer feed rate at the machine those axles would be way more reliable. Also the axles shown for SRAM are smooth and plated all around.
Thanks so much for the comment, really insightful! I think you might be onto something actually. Looking at the photos between the 2 failures, they both broke at prety much the same point too... Ill def keep this comment in mind when reviewing cranksets in the future!!!
@@TraceVelo I've got the exact same crankset, the axle is aluminium as well, but the axle has been anodized black. Would that prevent the fatigue issue then?
That might be the case too. However, I think the main reason the aluminium crank snapped at the same spot because of the nature of aluminium itself which is much softer than steel. In other hand, when I was doing a research on lubrication application on aluminium rod using pin on disc machine, I found that different type of lubrication also plays important role in reducing friction especially at those wear marks. When I looked the wear marks under SEM machine, the crack propagation is much wider on unlubed aluminium rod compared to aluminium rod that were lubed with conventional lubes.
@@ruudboek Whilst anodizing is a form of layer or case hardening (can be 3x harder than the raw material) it won't stop fatigue. It will put it off for longer, but by how much? How long is a piece of string?
It kind of depends on where and why these failures are happening. Is it from the outer diameter under tension failing, or the inside diameter under compression when the spindle flexes under load?
It is an improvement regardless to material rigidity. Compared to an identical piece of material that is untreated (and barring imperfections) it should last longer.
Note: The harder you make something, the more brittle it also becomes. It can be a bit of a trade off.
For a constant given load, lets say a motor running a generator and the driveshaft is aluminium, with anodizing that shaft could be a lighter item from less material lasting just as long as an untreaded AL shaft. BUT that's for a constant loading through that shaft (the drag from the generator unit), our pedalling on flats, up hills, away from standstills isn't a constant, it's always variable loading.
A very slight possibility of anodizing also being detrimental though if the inner diameter is also anodized. As you pedal and the spindle flexes, the inner diameter compresses whilst the outer stretches, ever so slightly but still happens, hardening those layers will make for a stiffer axle... for a while, then long term fatigue will catch up at some point. An essence of stretch and elasticity are good properties for longevity, not something aluminium is very good at.
@@two-eyedRoy from the pictures of the failures at 8:20 I would say that it looks like the crack formed on the outside where the alloy yielded under the stretching induced by the torque of pedalling, benefitted by the surface finish. I come to this conclusion because the outer edge is very clean, almost 90 degrees into the material with crystaline looking surfaces which is typical for strain hardening in aluminium, while the inner edge looks more fuzzy and broken out like the material was twisted apart. I know that I might succumb to my conformation bias right here but I strongly think that the outer surface gave way first.
I remember you promising to report back on the aluminium spindle's durability back then. Top lad!
great video. Thanks. I just checked all of my chinese cranksets. I’m glad to report that SMLLOW, iXF and Claw cranksets have steel axles.
Nice, thanks for the comment Mark, good to hear you are running steel axles, will def help with longevity!
Great vid as usual Luke! :)
I can see the failure point in your crank spindle.
11:34 - 11:36 as it rotates through the light you can see a hairline crack including a couple of pits in keypad 8 (break the screen into 9 [3 rows, 3 columns, 8 is the bottom middle square]).
Can't say when it'll go, but when it does I'd put money on that area being it.
I doubt changing the machining (from that fast rough cut that's almost a thread to something smoother that takes longer) would make any difference as that hairline looks to have been present during machining (evidence being the little facets either side of the crack that glint in the light)
That does also imply the the bar stock was not forged and possibly not extruded either (could be wrong on the latter, not entirely sure).
Like the '80s Castrol ad. 'Oils ain't Oils', metals are no different. AL 7075 cast is rather inferior (crystaline structure) to extruded 7075 (crystaline structure uniformity) and then forged 7075 is slightly better again (crystaline structure uniformity under compression). Those three states are also increasing in cost to purchase.
A note on advertising jargon: A 'billet' is just a single piece or chunk of material. It doesn't define any level of quality.
A billet of junk material, is still junk.
It's a fad term from the car wheel industry that since got picked up by motorsports and now any manufacturer wanting to hype up a product now faps into their own face about billet this/that in their advertising.
The term/phrase you want to read/hear is 'Billet Forging', because the Forging gives the material it's best structural properties.
@TraceVelo : Smoother surface will increase the resistance towards fatique. The 'lines' of milling will increase the chance of tear or rupture. Smoothing it with sanding paper will increase the durability in regard of fatique. The initiation of the cracks are on the surface, smoothing it will decrease that initiation of a crack.
Luke maybe you won't read that but i want to let you know i'm an avid (and subscribed!) viewer from Spain that really enjoys your vids. I value inmensely your honesty and dedication to this sector of cheap bike stuff. I own a cheap mtb kinda converted for road use but i plan to build myself a proper disc brake road bike this year using a frame and parts reviewed in your videos. Just wanted to let you know you have active viewers from all around the world that find tremendous value in your work. Take care mate, and keep doing this forever please :D
Thanks so much Angel, what an awesome comment! I put alot of effort into these vids, and comments like these really make my day!
Hi Luke! Just wanna share my experience here on this exact crankset too!
I had 2 of this exact cranks in 165mm. Both had the same problems where the GXP mounting surface on the crank is slanted/offset, such that my chainring doesn't spin in a straight-line. It cause my chain to rub both sides of my FD even in 50-11 gear.
For the #1 purchase, I told the seller about the issue where my chainring doesn't spin straight. The seller kindly told me that the chainrings are CNC-ed to a good tolerance, and it must be the cranks that have issue.
With little questions asked, the seller sent me a new crank, and the problem is solved.
For my #2 purchase, the slant/offset seems even worse. Worse part is no reply from seller yet.
So kinda hit or miss
Wow interesting. Maybe in your case, the parts were damaged/bent during shipping, which led to the issue. The packaging on some of this gear is a little hap-hazard for a 3 week shipping period from China... Thanks for the comment tho, always good to hear other peoples experiences!
@@TraceVelo still worth it for the price! Risk it for a bicsuit!
I had a ZRACE Hardrock MTB crank where the left side arm was held only by a single aluminium bolt that goes into the center of the crank. Unlike Shimano it had no pinch bolts, and kinda looks like a GXP setup. After almost a year of use, the bolt snapped it's head. A similar crank to this is the Fovno Ghost.
I now went for a Prowheel MPX-11 crankset where the left crank arm has pinch bolts Similar to Shimano Hollowtech. It's a bit heavier but it looks like it will last longer.
@@sepg5084 oh damn, I'm familiar with the Fovno and GXP stuff, and always thought the crank bolt torquing to like 40Nm makes it bombproof
I had the same problem here. They sent me new rings hoping it would solve the problem but was the same. Turned out the axle wasn`t bonded in straight with the arm. They where kind enough to send a new arm out also and this one has been fine.
Cant wait for the fully carbon brake caliper video. Been in my shopping cart for a few weeks now.
Shimano HAS used aluminum axle!
12 years on my Shimano DEORE LX crankset,and those are still running!
The stiffest cranks that I ever used! Excellent cranks! Greetings from Croatia 😊
Those carbon fibre caliper brakes are spongy, totally NOT stiff. Only good for the rear wheel as ABS caliper brake.
The whole thing flexes.
VERY light indeed!
Yeah agreed, they are light, but they are mega spongy
Try the Aliexpress C.Creek EE brakes. About $160 for the pair.
Stiffer than Ultegra R8000 calipers.
I was wondering when you would make an update on this crankset and it finally came! This is why I always consult your channel in regards to these chinese parts. I have the same crankset and it feels so great to ride! The bottom bracket was kinda iffy tho so I got that replaced quickly but seeing how much punishment yours was able to take just gives me peace of mind that I'll be able to ride my bike without worrying about my crankset. Awesome stuff as always Luke!
I am glad ur been transparent with all the products you review
Thanks Tomer, I try my best 😎
I love that this video dropped within hours of Hambini's video of his 300 quid Dura Ace crankset also failing. You get what you pay for I guess....
1) You can go cheap, little heavy & safe.
2) Cheap, lite & not safe (then why manufacture the product?) Probably stupid engineering and less ethic.
3) Reasonable price, lite & safe (probably shimano tiagra 105).
4) Expensive, lite & not safe (ultegra & duraace). Evil Shimano, the vampire blood sucker.
Yeah I guess it shows all manufacturers can suffer with QC and defects in their stuff!
I worked at a bikeshop in highschool. There was a old man who rode his bike 365 days everywhere and its a was a old alu raleigh frame for commuting and he told us that when he was making a turn down a hill he felt the crankset area loose and he couldnt transfer power. As it turns out the frame gave at the bb area due to fatigue and only the top welds where holding it. Nothing bad happened since he has braked already. That was a cool experience.
Luke mate, we respect the graft, don't be apologetic about the subscribe&like/sponsor slots. Far more interested in Siroko than the 5 property investment videos I have to sit through before starting the vid
Hi there.
5:30 Your right knee reaches more under the handlebar then you left, from top view, as if you have 175 mm crank on you right and 170mm crank on you left.
8:20 Fotage reveals cranks break toward the non-drive side sugesting the load was applyed on the left crank uppon breaking.
To hinder axle break, try applying a pull on the drive side while applying pressure on the left crank.
That is, help your left crank spread the load buy pulling simultaneously on the right crank, ballance the load with opposite load.
Getting 7000 miles out of chain rings that cost $34 to replace is outstanding. Full stop. Are there really people who think parts should last 70,000 miles? I'm doubtful that 99.9% of the cycling community will ride 70,000 miles in their entire lives. In my observation, almost everyone replaces bike parts to get the newest thing, or other vanity based reasons, not because they actually wore it out.
I bought that crankset (chainset) based on your video, put a few thousand miles on it on a road bike, then converted it to 1X and I'm using it on a gravel bike now, beating the hell out of it. So far, it still looks new.
$34 for an inner chainring is nothing special in the deals department. I just paid $26 for an FSA Pro Road chainring, shipped!
@@CrabgrassFarmer Got news for you. Most FSA is basic aluminum stuff. Nothing wrong with it but nothing special either. Besides, this is not an inner single chainring. It is inner and outer machined from a single billet of aluminum, one piece. Requires considerably more material and work to make it. Far stiffer and lighter than the typical two chainrings held on with 8-10 bolts configuration that most cranks use.
@@elephantcup I stand corrected. Thanks. I realized sometime after I posted that this was a one-piece crankset and didn't get my comment deleted timely.
Great video, interesting to see a crank failure from trace and a Dura ace crank failure vid by Hambini on the same day! It seems the cheap ones no worse than the most expensive…
Luke killing it with the ELI5 for fatigue limit!
Thanks Chris! Yeah I tried to keep it as quick and simple as possible, metal fatigue is a massive rabbit hole once you start researching...
I love these update videos on parts from China, keep up the great work Luke! You’re my favorite bike content creator. 👍🏼
Awesome! Thank you Vazione!
Fully agree Vazione, Luke's videos are brilliant!
Never thought I’d say this but Campagnolo is looking like my next Groupset.
Great video ! I ride a steel frame
roadbike, the only carbon fibre on it are my brake levers.
Always look forward to seeing your videos .All the best!
Great to see a follow up review long term. Really enjoying the videos.
Excellent video with scientific background to go along, cheers mate 😉
Glad you enjoyed it
I really appreciate this research review, it tooks a long time to know what happened. And I see Micronew brifter is still attached on your bike.
youre a godsend mate, so underrated - hope your channel grows massively!
Thanks Akkas!!! 😊
I think apart from the smaller diameter of 24mm (compared to DUB at 29 or BB30 at 30mm) the material on this crank is of inferior quality, despite supposedly being made of the same 7075 aluminium as more expensive cranks. It looks like it's cast instead of forged. Which would explain why the grain structure won't be able to cope with loads as reliably. It would also explain why it is that cheap bc it's obviously cheaper to produce. Getting the steel axle version is probably a better idea. The manufacturer seems to agree.
Another excellent video Luke. Both educational and entertaining. Kudos for making these whilst holding down a day job. I am still putting off editing my own GoPro videos from last year! May your subs continue to roll in and the sponsors keep sponsoring 🙏🏼
Thanks Aneirin, really appreicte the comment! Yeah, with these videos and a fulltime day job, free time for me nowadays is an absolute myth 😛
Luke you should try our the EE Brakes that are on AliExpress for sale. I picked up two pairs and love them. The ZTTO brakes that you've picked up are really light but are extremely narrow (rim width has to be less than 24mm). Some people who bought them say they are based on the old Ciamillo Lekki8 brakes? Would be great for you to confirm that info in your review.
I really thought this channel had 200k+ subs because of the production quality
Thanks so much dude! Maybe one day I'll get there!
I had mine FSA SL-K Light 386EVO chainset for seven years without any problem. The axle is forged AL7050 aluminium.
I've got a cheap IXF 1x crank on a 29er hardtail I have.....Been on there 3 years and doesn't appear to be crap as yet....I haven't a clue whether it's an aluminium axle or steel as I just fitted it when I got it.....It runs well with a SRAM GX setup....
I even stuck one on an old 26er hardtail last year (1x11 conversion), when I couldn't get hold of a Shimano kinda thing, and it's been pretty damn good.....It also runs very well with a SRAM NX setup.....
I do check my chains regularly with a chain checker and just replace parts when necessary.....On a 1x chairing, it's just a piece of piss to stick another one on....Just keep your bike clean is the best advice....
Saying that, I don't really put much load on the pedals as I'm pretty ancient and only weigh 9.25 stones and it's pretty flat around here in Peterborough UK..
Good video again fella.
I'm running a cheap Chinese crankset on my bike as well, though not this exact one - mine is made by Litepro and I use a 1x drivetrain. But your video made me check the specs and I'm certainly happy to see that the axle on mine appears to be steel, so I don't need to worry (although I'm not a masher by any means, especially as there are basically no hills to speak of here in Shanghai).
Awesome, always good to check!
Great as always, for someone who's about to build a bike just off parts from Ali express it's really helpful 🤝 my g
Good good I'm happy I've got 3000 miles with bugger all wear out of my Cannondale Spiderring, but as a mountain biker in the Pennines 1000 miles out of a chainring is a miracle!!!!
Repeat again what Luke said - because of the failure mode aluminium it's hard to be sure that the crank I have is fine, but so far so good. That caveat out the way, I got a Zrace DUB crankset as part of my Sensah "groupset". This is a fairly standard 5 point spider bolted onto the cranks (same SRAM style as Luke's) with individual aluminium rings bolted on to a spider. I was getting a lot of BB creak which after a lot of messing about I realised was not the BB at all but the bolts on the spider. No matter what I tried the creaking always came back so I got the "Zrace Hardrock" one piece replacement - ie both chainrings and the spider machined out of one piece of aluminium. This comibination so far is really good - done 1000+m on it. Also it's much easier changing / replacing chainrings this way than the traditional 5 point spider - just 3 torx screws attach the one piece chainring to the cranks so it's quick and easy to swap. I'm a heavier rider (98kg) but I don't notice any flex in the crankarms and the Hardrock chainrings are showing little wear. Hopefully because it's DUB axle it is less prone to this sort of failure but who knows.
Yeah hopefully that wider axle diameter will make the difference. I certainly havent heard any stories of Sram Dub axles breaking, so fingers crossed!
I have a cheap IFX crankset in the box, to be installed tomorrow. And I just checked it w/ a magnet, and they were attracted to each other. Kind of like cheap love.
For me, that is one well structured, honest and entertaining video. Thanks. 👍
great Video, you really improved your Video quality! Perfect Mix of Entertainment und Science
Awesome, thanks!!! Yeah I'm always trying to improve my stuff, so glad it's coming across 😄
Wow you are releasing one video after the other recently, is it already christmas?^^
Ha, glad you noticed! I've been pushing myself to step up the pace recently
I was going to say the same thing. You sir beat me to it
UsefulMuffinCat is right. Those machining marks are definite stress raisers and will contribute to fatigue failure. Most engineering texts counsel against this kind of finish. I've had other components like seat post saddle clamps fail from similar poor design.
On fatigue failure, it is not unpredictable. Typically, fatigue cracks will be evident and growing for some time, until there is not enough material cross-section left to maintain structural integrity under load and then the rest of the structure has its strength exceeded and it fails in shear.
You can see this by examining the surface of the failure. Where the face is shiny, that is from sides of the growing fatigue crack rubbing each other smooth as the component flexes under load. The rough surfaces are where the rest of the material finalyy failed in shear. This is evident in a couple of the shots on your video.
I have serious doubts about those rings and axle being 7075-T6 at that price point. The average punter will not be able to know whether he is getting dudded or not. The vendor is likely using something cheap and easy to machine, confident he will never be caught.
7075-T6 is challenging to machine and requires expensive cutting tips. Hand tools hardly touch it and drilling it requires brand-new sharp bits, or your drill bit wanders all over the place. To resolve some chain snatch issues from poor tolerances on a similarly priced MTB chainring, I found the tooth thickness was easily modified with an old file. No way they are 7075-T6 as claimed.
Does this help? I enjoy your videos and watching you progress and mature your presentation style. Keep it up.
You're correct... aluminum will fail, given enough loading events. Plus, while steel is ductile, and will elongate and stretch prior to failure, giving you some heads up that it's going to completely fail within time (hopefully enough heads up to notice before full failure). Aluminum, however, is a very brittle (the opposite of ductile) material in failure. So aluminum DOESN'T give you much of a heads up... so, you got that to worry about now.
Steel fails in a bunch of different ways (including fatigue if there is a stress concentration or high loading). Not all of them are ductile failures, depending on geometry and the specific type of steel used.
I bought the same wheelset and crankset after watched your videos, thanks a lot dude
You are my favorite youtuber but also my Cheap Carbon Fibre hero.
I will keep eating full grain in hope of achieving my own Chinese carbon bike soon.
Fantastic video, I nearly bought the crank you reviewed but having second thoughts now. Will stick with trusted brands.
Thanks for the heads-up; I just ordered the steel axle version of the crankset. I'm a heavier rider and I really appreciate the follow-up on your videos. When it's all said and done I probably haven't saved much money over Shimano (new steel axle crankset was $31, $20 shippng) but I like the look of these better, setup was easy, and shifting is no issue. And the faux-speedplay pedals are still going strong - that was a great purchase!
I think imma cop the steel axle version. Also can't wait for the rim brake video
hoop strength is something most people will never have to deal with most car drive shafts that put power down have a aluminium shaft somewhere on it so a small bump in diameter has a huge improvement on strength like 4x
Your subscriber ratio is actually way higher than most channels!
As always a fantastic episode. Entertaining and informative.
Glad you enjoyed it
I'm glad I stuck with my factory cranks, I was thinking of getting some but I'm going to stick to mine
A very long time ago bikers had a trick as a life insurance. They put a wooden pin in the fork tube. Maybe you could do the same thing with the crank axle to be on a safer side.
Yet another excellent video, glad to see you're settling into your new pad. Would be interesting to see what some non destructive testing would reveal on your crank. Would make a really nerdy metallurgy video. Keep them coming.
Just got my 165mm Senicx (BSA68) to try out shorter crank arms on my tri-bike. Comes with pre-load adjuster. Smooth finish on axle. So far, worx well enough.
Great video. When I did my build last year I used the same crankset (I also used the same 'Speedplay' pedals). I'm a heavier rider so I'm going to replace it with the steel axle version. Your updates are much appreciated.
Just bought a similarly-priced shorter-armed crank arm Goldix (!) crankset: arms are aluminium but axle is steel!
Great Video! I had the exact same problem on the exact same cranks. Axel snapped as i was pushing off from a red light. I'm 6'2", 210lbs and had about 4500mi on the cranks. Company replaced with the steel axel version under warranty and so far ok. I will give it one more year and if there are any more shenanigans, I may just spend the $$$ to go Shimano or explore the larger DUB tech as you suggested. Thanks again!
From which store did u get the steel versión? Could you give me the link if you have it please!!
Great video! A have an Goldix crankset, with steel axel. Hope it will be ok to ride. Cheers from Moldova!
I'd love to see a similar series focused on mtb or gravel bikes. Keep up the great work!
There's another issue you didn't mention. The crank arms are dead straight. Other brands make them slightly curved outwards to give space to the shoe of the rider. The CVR cranks were unusable for me. I had to put spacers on my pedals to avoid the shoe touching the crank every revolution. I don't recommend these cranks for this reason.
Nice work. Your editing is really good. Ciao ciao
Thanks Otavio😅 I've been trying out some new editing techniques recently, so I'm glad it's coming across!
Having just watched Hambini's DA crankset and now your super Ali one (and all your other videos), I maintain that Shimano 105 11 spd rim brake is the Goldilocks groupset. Shimano, if you're listening, leave it alone!!!!!!!
There was at least one generation of Shimano road cranksets having aluminium axles - in particular, the 105 FC-5600 ones. I did have one and it did have an aluminium 24 mm axles, but with somewhat thicker walls. It was one of the first generations of Hollowtech II axles I think and the crankset weight as near as makes no difference the same as the next generation of 105 (FC-5700), which came with steel axles.
There were some reported cases of Shimano aluminium snapped axles, but then again there are just about as many featuring steel Hollowtech II axles. I guess there are other factor in play there, such as the parallelism of the bottom bracket bearings or preload force.
Can't be too bad if you're sticking with it for the time being, thanks for the entertaining and informative content, looking forward for more. I especially like the budget bit. I had my bike nicked; a felt 2014 mountain bike £475. Went to cash generator and found amongst the others a boardman 8.6 mtx, it was scruffy it was stuck on the middle crank out of 3x and tektro hydraulic brake, 700c. Because I've been riding in middle crank for 12 weeks I'm thinking I don't need 3 up front just a single 9x, then you're content popped up and it's energised me to shave off the weight even more, the boardman cost me 300, new in the shop 575. So it's kind of screaming out up grade me, I'm starting with the front crank then elite wheels then a 1000w electric motor! Just joking
I ordered the Goldix RX crank arms (the ones that look like ROTOR) in 165 when the turned up they where basically these crankarms but without the CVR/Hardrock logo so I checked the listing and they don't do a 165 in the "ROTOR" style (my fault for not paying attention basically) so I suspect Goldix/CVR/Hardrock/Zrace etc. all pee from the same pot.
Cranks have been great to be honest they have the steel spindle and I have put them on my road and gravel bikes. I don't do much road but 12000+ km on the gravel and so far no issues. Although I don't use their chainrings as both my bikes are 1x.
Nice, thanks for the comment Chris, always good to hear some other experiences with these parts! I think having a steel axle will really help with the longevity of your crankset!
@@TraceVelo Well to be fair I'm 5'5 and weigh 58kg soaking wet, so I don't worry too much 🤣
Thanks, Luke. I'm gonna check my ONIRII ATTACK crankset before I ride it. (Not that I put out much power.)
To check whether yours is aluminium or steel, just put a magnet on the open end of the metal shaft on the drive side - which can be seen at the start of Luke's vid.
Love the teaser for future videos!
Just about every BB30 crank has used an aluminum axle since Cannondale invented the standard two decades ago. The problem isn't that fatigue curve per se, it's something in the uniformity of the metal or the manufacturing that's changing the slope.
Yesterday I was watching Hambini's video about Ultegra and Dura ace crankset problems. Today is yours. I'll start to wonder if I can put a sail on my frame
Dude. With those hand movements, you should become a magicians assistant!! 😂😂
Great video as always Luke! Your videos are the ones me and my mates look forward to. Esp for budget options. Your coverage and review and update on the ltwoo and sensah groupset helped us allot on the decision. Thanks for all your hard work luke truly
Awesome, thank you Wasabe, really pleased you enjoy them!!!!
Can't wait for the new crankset and full carbon caliper review
Do you ever buy any cycling gear from your LBS? Shimano did use aluminum (24mm) in some of their earlier generic & 6600 series compact cranks. Major brands (Shimano ,SRAM & Campagnolo) although cost more I am convinced that they perform better and a better value. My shop is totally independent (no contacts to anybody & sell many major brands other than Giant , Trek , Cannondale & Specialized) and I have been working on bicycles for 50 yrs so I come with a little knowledge. Thank you for looking into the various component brands out there. I think you will find that the Chinese made parts will work OK ( everybody's idea of OK is different) but will not last as long as the original designed part (ie. the Cannondale copy chainrings). We live and hopefully learn everyday. Keep up the good work.
So you'd rather have Shimano's broken crank arms for $400 than a broken spindle for under $100😂
Are aluminum axles unusual? Our wheels are running on aluminum axles. Also, some mountain bike cranks use aluminum spindles. Those have to take the load of landing jumps crooked, casing landings, and high speed rock strikes while standing on the pedals. All fine.
With that said, I’m not sure large aluminum spindles are preferable. Smaller diameter allows for larger, more durable bearings.
Chainrings, like cassettes, will wear and may need to be replaced after about every 3 chain changes (providing the chains are not over-stretched before replacement as your cheap chain was). The problem isn't so much that the teeth become prone to breaking because they are thinner, it is that they wear on the contact edges and when you put on a new chain it only engages with the first one or two teeth on the chainring thus putting all of the force on those few teeth. This is exactly the situation that you showed at 2:52 in your clip.
I'm tempted to say the crank you showed hasn't failed because of high cycle fatigue, the theory you presented. I'm fairly confident posting this comment because of the very limited use that crank had and the extensive portion of brittle fracture shown on the broken surface, while the typical surface associated with 'beach marks' (high cycle fatigue propagation marks) cannot be clearly observed. I'd say the axle failed because of crack instability after a very limited number of deformation cycles (Linear Elsatic Fracture Mechanics, LEFM) from a pre-existant defect, likely way bigger than the tool marks you pointed. Moreover, I wouldn't be surprised if the original defect was on the inside of the crank: the outer surface is easy to inspect and I presume (hope...) Chinese manufacturers do visual quality checks on their products, while an inspection on the inside is way more expensive and time-consuming, but this is just speculation since I'm already saying waaaay too much from such a picture. The fact that 7075 T6 Al has very low fracture toughness doesn't help at all. An overload as you described may have caused this type of fracture, wich is fairly common on high perfomance aged Alluminium alloys.
But the basics you reported are true, the surface of the crank is indeed not polished but 'roughly' finished by tool (looks Ra 3.2), which does not help with fatigue life, no matter if high cycle or low cycle. The standard of the industry for axles is a smoothed surface blasted with high energy media in order to induce compressive strain on the surface, improving fatigue life and closing non-visible defects.
Great video anyway.
some old shimano ht2 cranks like Fc-m580 had an aluminium axle
Ride it for a few years even in winter without any failures
Cant wait for the Carbon rim brake review, been looking at crane creeks but its just too expensive.
Yeah I've been fiming that episode today. Still have a lot more to shoot, and obviously all of the edit to do, but I should have it up by the end of the month!
@@TraceVelo glad to hear it! Does it look good?
My OEM 3x lasted over 6 years 50k miles give or take when it did wear out I had to get a cheap 1x off Amazon good thing the shop I used had no trouble getting it setup after 3 bottom bracket that is
Thanks for the video, Luke. You're always very helpful 👍
nice new upload luke
Thanks! Been working my nuts off on this one after work over the last week, hope you enjoy it!
@@TraceVelo i really enjoyed your videos luke, i already watched all of your videos
I would take the 25g penalty and get the steel version I reckon. Cheers Luke!
Worth noting perhaps that Praxis use 30mm aluminium axles but steel for their 24mm axles.
Great video,I see the ZRACE Rx road crank has a 28.99mm like Srams which is great to see.
Thanks for the info and what to look out for, I really appreciate it.
More good stuff from Trace Velo!!👍
Aluminium chain rings don't necessarily mean a short service life, I'm still using my original 1985 suntour cyclone and Shimano 6200 cranks and rings and there's no issues.....Probably because the Japanese cared about their customers back then....unlike now where they just want your money....glued together dura-ace anybody??
I sheared a Cdale SI crankarm right off the spindle a couple years ago, and had replaced the crankarm bolts because they tended to strip easily, for me.
Great content! The Shimano's crankset Tiagra FC 4650 has 815g, with a steel axel...
Minimaze the height is cool but interesting value the risk...
🤘🏻🤘🏻🤘🏻🤘🏻🤘🏻
Thats actually pretty good weight wise, I assumed Tiagra stuff would be heavier...
Great work again and again
Shimano did make an aluminum hollow tech spindle for one year but abandoned it for the hardness of steel. The spindles are all forged, and at 24mm your not paying a big weight price for the stiffness and hardness you need.
About the 'all carbon fiber' calipers, i've had 2 sets, first one was too narrow for my 26mm width winspace rims, other set was ok, i had to add an elastic on the caliper to help it get back to its open position, and there's a lot of flex in it when braking, so i can't wait to see what you have to say about these 🤙
My two bike's cranksets are made in Japan (FC-M550 & FC-M952-5).
Back in the Stone Age (well,1970’s) during my Road Racing days I broke 2 Campag Record cranks ..above pedal thread. Early 2000’s had 3 FSA Carbon Crank fails when pedal thread insert became unbonded...Seen an awful lot of Shimano Road Cranks fail in the last while..so? Would say from my experience of riding Chinese Carbon frames from Ali Express for the past 10 years that the old argument of rubbishing these products ( often promoted by Mainstream,Overpriced Bike Brands,also made in China) is mostly inaccurate! Those cranksets you feature ,if branded by a company beginning with s and ending with m...would cost about £350! Prob would choose Steel 24mm axle though.
Legend.
Best of RUclips.
Another top video Luke.. love.your content...
Whats the pedals on your disc bike?
Bought these cranks because I was in need of new cranks in the summer of last year and you recommended them and well...they fit my budget. Since I saw this video I was a little worried so I took my cranks off my bike and checked the axle and it looks good. But it kinda looks like steel to me. So I took a magnet and my axle is 100% magnetic. I googled 7075 and it is basically alloy with zinc neither of these materials is magnetic. So am i right assuming my crank is actually a "newer" model and made of steel?
Yeah sounds like you've got a steel axle, so you should be golden!!!