Years ago I bought an aero fork, it was ridiculously expensive at the time, I decided that I would cut it myself (had the jig and a hacksaw). After doing so, a buddy looked and said you cut it too short. My local shop said "you're fucked". But I just wrote to the manufacturer, told them the TRUTH that I was a right bellend and they sent me a brand new fork. Honesty pays.
During buildup of my (Pina) frame, the supplier of the handlebar forgot to send the pressure plate that goes inside the handlebars to spread the transmission of torque onto the fork. As a result of shite assembly instructions, videos and scope of delivery, I cracked the fork during assembly, even though I used 1 Nm there's a hole now. I reached out to the shop about the missing part, but they're sticking their heads into the sand. We're going to court early next year. Wish honesty paid for me ...
At 6:32 there is an error in the PowerPoint animation(it might be something to do with not checking the pen was working), the top cap SHOULD NOT touch the bung, there should be a small gap. It is correct on the webpage and on the Look assembly video. Thanks to Klaus for pointing out my crap PowerPoint skills. www.hambini.com/increasing-the-length-stack-height-of-a-fork-steerer-cut-to-short/
Oh my god! This couldn't have come at a more perfect time. I was just searching for extending steerer tubes because I cut mine too short. Thank you Hambini
Just what I needed! Seems that VeloBike already makes a really robust version of this - it's basically the same but the expansion bit is extra long for more strength
The top pinch bolt of the stem won't put any force on the carbon steer tube. So when you pull up on the bar to jump over an obstacle, you don't have the same clamping force on the steerer. If the the bung isn't expanding properly, it can slip and the stem slides off the steerer. Not to mention that the plug itself can damage the steerer if not sized correctly.
I have never cut a steerer too short - except when I did. I have a machinist build a piece with a tight fit and then epoxy it in. Worked for 4 years - but Alias it was a 3T Exploro so I just gave up on all the other flawed other design details and sold the frameset. The star nut threads where integrated into the press fit piece. Stem was half on carbon and half on extension. Allowed for more resistance to rotation.
I did this with a machined titanium tube ,it was tight in the forks and stepped out to steerer tube width , after which it was epoxied into the fork...40,000kms no problems...it was a 3T fork with a very good internal fit in the tube.
I did this with a fork. I wanted an extra 5mm added to the fork. So I cut a 5mm piece off of a steerer of another "damaged" fork. The 5mm piece was of the same dimension as the steerer of the fork needing repaired. I then epoxied (using JB Weldit) the 5mm piece in. Then I used a really long expansion plug that is 80mm long (the one in Hambini video is about 25mm). I did this repair on an mtb fork and have been using it ever since. Absolutely solid. Now my extension was only 5mm, which means the stem was clamping on both the 5mm piece and the original steerer at the same time. However, I wouldn't recommd this method if you needed a much longer extention (eg: 40mm) where the stem could ONLY clamp to the 40mm extension piece and cannot clamp to any part of the original steerer.
Cutting steerer tubes is always a job I take loads of time over. Measuring a good few times before I cut. A good saw guide is recommended to cut the tube square. A cheaper alternative is to use a couple of jubilee clips as your guide. Oh and when you cut carbon wear a mask the dust is nasty stuff. Enjoyed the video cheers.
Nice job. I did the same fix using a similar expanding plug. The only difference being I used JB Weld to glue it into the steel steerer tube on a MTB fork. Cheers :)
That's actually one of the sketchiest fixes I've ever seen, introducing a weak spot and potential dimension tolerance problems right where the one of the most critical connections on the bike are.. On a steel steerer tube I maybe would give it a pass, but on carbon - no way.
As an owner of a very early GT Zascar Alu MTB, it had the first discbrakes I had seen by then. I then found a ligther Vision Kilo carbon frame which I replaced from the original, and the steerer became a little too short, but still mostly useable! I have lately found a Chinese extension part, like yours with a round top, making it able to get the handlebar moved further up. Finn. Denmark
@@guinieroo Well I haven't actually had a purpose to put them on my bike.. But my former alu frame had a little shorter head set mount/part so it is a little short for my new Carbon frame. Nothing serious, but I would like to get my handlebar and stem a little further up, in spite of a small increase in weight.
just bought a new fork for my madone SLR. I didn't cut it too short, rather i've just rapidly become an increasingly old bastard over the last 3 years or so. with that said i searched high and low for a solution like you actually manufactured since i only originally wanted to increase the height by 10mm. it was unlikely to be available in my case since the madone has a D-shape steerer tube but it would be great for other if you add that to your lineup.
This is the reason why I just recently on purpose cut my steerer too long :-) I don't want to find myself in the same situation few years down the road.
The Delta brand steerer extender works perfectly well for aluminum and steel and is attached more securely than any stem on a threadless steerer. It’s only drawback is how it looks.
With this fix... say goodbye to your steerer tube and your front teeth all in one simple failure. But, if you really want to do this kind of fix, don't.
One of my 2 Cube bikes from 2008 came with a compression nut as you have shown at the beginning of the video. The odd thing is that people said about that particular type of steerer nut is for carbon forks, but that bike had an aluminium steerer tube (and that bike still has the same awesome fork).
Compression plugs work fine with aluminum steerers, as long as the diameter is correct (typically aluminum steer tube walls will be thinner than carbon counterparts) but it doesn't work the other way - you must not use a star-nut with a carbon steerer!
@@userkmunhwaock That was my assumption also. Now, I actually would group Al. and carbon on one side as "softer" and "easily scartchable" materials, while on the other side, Cromoly and titanium as harder materials. I would not use a star nut on anything else than steel and totally agree with the choice of compression nut for Al. parts, especially considering that the cones and sides (of the compression nut) are made of Al. themselves. As for the diameter part, these expand quite a lot, but it's irrelevant, as diameters are well standardized. Actually, I would use these on any fork and do not understand why star nuts are still put on any bike costing more than $200; it's probably $0.25 more profit.
Many many many years ago I had this problem with a bike i bought used, but the tube was steel with a starnut. My solution of course in the end was to sell the frame and buy a new one, at the time i designed a similar device that would go interference-fit into the tube to extend it but it was too much of a hassle for me to do it
I once bought a used bike on ebay that had a fork with (steel) steerer tube extended with a welded-on section. The thing was perfectly straight and true so I put it together with the spacers that raised the (old-time quill) stem up around 40 mm and had no issues. I figured even if the steerer tube somehow snapped in-two it was unlikely to fail without any warning. With carbon...I'm not so sure.
Well Mr Hambini, i would say you haven't put enough ink in your pen this day lol. Not a big fan of this hack, i get it is a last resort (I think you didn't emphasis this enough). But I would highly recommend first, you get a new fork. Because you are only relying on the knurled expander plug and bearing pretension friction to prevent any moment movement from the point of the knurled section to the top of the stem clamping, which i would say the user has, the top clamp clamping point, on the new aluminium bung that has a slack fit. This could potentially wear the inteface between the knurled section and the inside of the carbon, or worst case, the handlebars could come off in your hand due to wear from movement when riding. Also not a fan of those short plugs.
I'd be slightly concerned about using this, the compression plug inside the steerer, should match the clamping area of the stem, as the plug is trying to 'stretch' the steerer, and the stem is trying to squash it, they support each other if they line up. Where the expander is now below the stem it's acting on an unsupported part of the steerer. Same thing happens if you have a load of spacers on top of the stem, which is why most manufacturers recommend a max of 5mm of spacers above.
There’s no cause for concern with regards to clamping area as he’s using a machined aluminum extender. Aluminum steerers don’t use compression plugs. They use star fangled nuts. The sole purpose of the star fangled nut is to provide an anchor for the top cap bolt. The top cap is used to preload the headset bearings and remove play. It is only necessary for adjusting headset preload. Once that’s done, the cap/bolt/star nut are unnecessary. Carbon steerers use compression plugs instead of star nuts. But they serve the same main purpose. To provide an anchor for the top cap assembly when adjusting preload. SOME carbon steerers are not strong enough to withstand the the clamping forces of overtorqued stem bolts. And that is where compression plugs provide a secondary benefit. They do not stretch the steerer tube. They do provide additional support to avoid crushing the carbon fiber tube in cases of overtorqued stem bolts. This is why some manufacturers recommend specific compression plug designs and placement. Most manufacturers actually recommend a MINIMUM (Not max) of a 5mm spacer above the stem. Manufacturers do have a recommendation for max spacer height but that is for BELOW the stem.
This is only superficially true. The plug is in fact not an inherent design element of the headset. Just think about the sheering forces occurring when you pull the handlebar. At the places where the stem is going through the frame there aren't any internal expanders present. The forces during riding and pulling the handlebar which act's as a lever are huge compared to anything this kind of plug does to the stem. So if the stem can't handle almost arbitrary placement, the whole fork is not sufficiently strong in the first place. Squashing something twice will not help its internal structural integrity.
Mechanically a stem pointing up is theoretically better. However since all parts at all angles and heights are designed to manage the loads anyway it's rather irrelevant. Decide based on aesthetics.
Nice engineering work (at least I guess it is, I'm not an engineer) However I would sell the fork to someone running a smaller frame size and just get a new fork..or measure twice in the first place
I was told this time and time again as an apprentice Toolmaker, now I tell every apprentice. It’s the only way as I’m sure Hambini and his hairdresser would agree.😂
I’m quite impressed this is a neat fix. How much torque did you apply to the bolt that fits down into the original compression plug? I normally don’t go more than 5-6 nm to avoid stressing the steerer tube walls from the inside when fitting a compression plug.
Ideally that machined part should be bonded into the steerer tube so as to eliminate any small chance of that piece turning and also the adhesive would fill that 2mm difference between the inner diameter of the steerer tube and the outer diameter of the machined piece eliminating any crush on the carbon part of the steerer. As is the compression part of the compression plug is serving a purpose by holding things in place, but it is not doing it's main job of preventing steerer crush as it is now under where the stem is clamping the steerer. Granted there is only 2mm difference but that's still enough to crush via over tightening or crash related forces.
Crush is only when the external force exceeds the internal force. I always use the same torques on the plug and the clamp to reduce risk compression deformation of the steerer.
That’s not a headset Hambo it’s a steerer plug! There is a kiwi company,who’s name escapes me, that does a high quality version of this to extend head tubes by up to maybe 35 mm.
The only issue is you did you not line up the expanding pieces from the expansion plug so they are equal on all sides (same gaps). I made a boring 20 minute video explaining how even pro bike mechanics are installing these expansion plugs wrong and also the wrong length. Basically you want the length to go down pass the head set bearing, then you want the expansion pieces do go into the the steerer tube already a bit expanded so this way they go in pregapped the same on all sides, since there are 3 pieces with 3 gaps, one gap goes directly to the front of the bike, the side gaps will now face back angled, the faces will face the handlebars which is important in order to protect those ares from the handlebar hand movement forces. Great video and a good fix!
Why do people cut steerer tubes unnecessarily close / short. I leave mine a bit longer and just add a couple of spacers under the top cap. That way when you come to move the fork on (between frames / or selling) you always have a bit more stem to play with. Simple really.
I'd want the insert to closely match the internal contour of the carbon stem to prevent the stem collapsing from the stem's clamping load. This is particularly important when you consider the competence of your customer. If they can't measure and cut a stem, they're not going to understand torque wrenches either.
Those amazon sold extenders are often listed as steerer extenders for MTB....makes sense as the steerers are mostly alloy. I actually like the idea of this extender Hambini has fabricated as you're that plug further into the steerer and then clamping into the alloy extension which I prefer
I bought a bike brand new with one of those expanders installed. The shop that assembled the bike cut the steerer too short. The bike is meant to be used off road. I havent noticed any play but the stem is on the extender. It’s is a steel frame and fork ( gorilla monsoon). Should i order a new fork or is this a ok solution ?
@RollinRat Well I do appreciate your input, and the fact that you seem to come from a genuine place if caring, so thank you. I actually have a full carbon frame on one of my DH bikes and it's pretty strong. And I also have a carbon Renthal bar too... I prefer aluminum though because I don't like the take of stem and teeth. I've been riding DH for almost 25 years now. I was riding yesterday, and every weekend this season. I've broken a few bones and snapped a few frames, all to say I've made mistakes of my own. I've also raced with a 1999 Boxxer fork with a cracked brake arch, hit drops on a cracked GT LOBO and still send big jumps and drops on my cracked Santa Cruz Super 8. That's all to demonstrate my level of stupidity. Clearly, I'm not the brightest. But this thing is pretty cool, and it seems like it could work on my Avalanche front fork. Downhill forks are not as reliant on steerer tube strength as single crowns because the dual crowns can hold the steerer in place. And I can use my Da Bomb head lock to sandwich everything in place thru the steerer tube without even using a headset star nut.
To my mind, doing any of this is fraught with danger, which really hambini why subject yourself to it. The liability is too great. Although the plug extends under the stem enough for its grip, the plug should really be extended even further to a decent amount below the upper headset bearing, and the expander surface should be much more. To each his own, but bottom line if you cut it too short, get a new one, paint color regardless, just roll with it using a straight major color from the current paint scheme.
Absolutely agree. The plug seems far too short and likely creates a new stress point in the steerer tube - lateral forces would be basically concentrated where the plug ends within the steerer tube and only an inch or so of the carbon tube taking it all. Zoinks!
Alternatively make an aluminum insert/extender that is epoxy bonded into the fork with lots of overlap inside the carbon fork for max strength. No expander used. It is a one off repair that makes the fork a fixed (longer) length. It adds a little weight but no concerns about strength or where the stem clamps.
Any chance you could sell these, maybe in varying lengths? I had this issue last winter, and while looking at the expander wedge I though of basically what you did here, although I was gonna go about simply adding something that would look like a headset spacer between the seperating pieces to give it a bit of length I need, but I havent been able to find anything with the correct diameter, and I dont have access to any machine shop or anything.
What he made is available for sale by various companies. VeloBike makes one. The expanders are longer on the commercially available ones and so actually better.
@@DaveCM I ended up ordering the velobike one, I just thought it was too much $ for what it is. Doesn't help that its for a frameset that I'm more likely just going to sell rather than ride (didn't want to sell it in the state it was like someone did to me). I guess I will just have to ask an extra $100 to cover the piece!
@@Hambini Warning on page 10 of the Synapse Manual. Looks like the top cap has a built in spacer though. www.cannondale.com/-/media/files/manual-uploads/manuals/oms%20cd%20bk%20rd%20synapse%20disc%20en%20r1%20134911.pdf
For instance: www.cannondale.com/-/media/files/manual-uploads/manuals/2011_webOMS_127398_SuperX_EN.pdf Page 10 "Assemble the fork, headset, spacers, and stem without tightening the stem bolts onto the head tube. When the system is assembled, the carbon steerer tube should be 2-3 mm below the top stem. All spacers must be located below the stem and within the maximum stack height as shown. No spacers may be used above the stem."
@@vromaka Cannondale's are a bit unusual though. They use this SI compression assembly where the top cap threads onto the expander and you install both at the same time, plus the top cap has an outer sleeve that reinforces the steerer tube where it is clamped by the stem bolt. So you can't put a spacer under the top cap anyway. In any case I wanted a custom top cap so replaced the Cannondale assembly with a much longer pro compression plug which provides much better support to the steerer tube. That allowed me to use my custom top cap and as I have not cut my steerer yet have a couple spacers under the top cap with no issue.
I've seen a study done into reinforcing steerer tubes, the issue with solid insert is what people don't see is that under braking the steerer tube actually bows a little, so if you then add a solid metal insert the bottom edge acts as a stress raiser and move the point it bows at lower down the steerer, this could lead to premature failure, the out come of the tests was that Cervelo's method of bonding a tube in for a star flange nut was okay as long as it's not to long, and Campagnolo extra long expander were the best way add strength to the steerer tubes.
Wont the extension piece spin relative to the fork tube? If im doing that, id add some notch/keys to the bottom piece and extension piece. Just a peace of mind. Pretty much like those threaded fork to threadless fork stem adapters.
Why not make a machined alloy piece as you did but make the insertable part say 3 inches long or longer, then bond it in permanently? Poor steerer concentricity wouldn’t matter, nor would a flush cut carbon end, just design the piece symmetrical and with the thicker part oversized, then when the resin cures, set it up in a lath and machine the alum even with the carbon. Let it setup in a jig to keep it as straight as possible. The alloy piece can include threading for the pretensioning bolt. If the carbon is compatible with the alum alloy. I know they do make carbon bladed forks on alloy crowns and steerers. If there is any concern about the bond breaking, just steel pin the two together in a couple of locations.
I need to extent fork but not because I cannot mount stem but because I want it higher, original is cut too aggressively for my liking. I guess I need to sue some extension from amazon
![Blox Fruits Dragon Rework Update [Full Stream]](http://i.ytimg.com/vi/EqDAp8udhm0/mqdefault.jpg)
Years ago I bought an aero fork, it was ridiculously expensive at the time, I decided that I would cut it myself (had the jig and a hacksaw). After doing so, a buddy looked and said you cut it too short. My local shop said "you're fucked". But I just wrote to the manufacturer, told them the TRUTH that I was a right bellend and they sent me a brand new fork.
Honesty pays.
During buildup of my (Pina) frame, the supplier of the handlebar forgot to send the pressure plate that goes inside the handlebars to spread the transmission of torque onto the fork. As a result of shite assembly instructions, videos and scope of delivery, I cracked the fork during assembly, even though I used 1 Nm there's a hole now. I reached out to the shop about the missing part, but they're sticking their heads into the sand. We're going to court early next year. Wish honesty paid for me ...
Time fork by chance?
@@antonmothes3160 Oval Concepts (I think they're defunct now).
Seems like you didn't deserve a new fork did you
@@jaysparc and that's why (the surviving) manufacturers are reluctant to do that...🙂
At 6:32 there is an error in the PowerPoint animation(it might be something to do with not checking the pen was working), the top cap SHOULD NOT touch the bung, there should be a small gap. It is correct on the webpage and on the Look assembly video. Thanks to Klaus for pointing out my crap PowerPoint skills. www.hambini.com/increasing-the-length-stack-height-of-a-fork-steerer-cut-to-short/
so my cap shouldnt touch a bung?
@@RV-jq5pb Consult your local hairdresser.
Yes spotted that... if it touches the bung you won't get any pre-load.
Where do I buy?
Oh my god! This couldn't have come at a more perfect time. I was just searching for extending steerer tubes because I cut mine too short. Thank you Hambini
Chooch out Hambini pen extenders. My hairdresser loves the results. I'm bald, btw.
I did once and it is easy solution. Just mount stem underneath head tube. + Its also very areo
Aeroupvote
And you can put a little resthead on top of the head tube !
Better to cut a hole in the middle of the head tube. Canyon did this for Cadel Evans
Pro tip: skip the handlebars altogether for an aero look
Just what I needed! Seems that VeloBike already makes a really robust version of this - it's basically the same but the expansion bit is extra long for more strength
That VeloBike website is straight up crack for track bike fiends. I had never heard of it before, so thanks for this comment!
The top pinch bolt of the stem won't put any force on the carbon steer tube. So when you pull up on the bar to jump over an obstacle, you don't have the same clamping force on the steerer. If the the bung isn't expanding properly, it can slip and the stem slides off the steerer. Not to mention that the plug itself can damage the steerer if not sized correctly.
I have never cut a steerer too short - except when I did. I have a machinist build a piece with a tight fit and then epoxy it in. Worked for 4 years - but Alias it was a 3T Exploro so I just gave up on all the other flawed other design details and sold the frameset. The star nut threads where integrated into the press fit piece. Stem was half on carbon and half on extension. Allowed for more resistance to rotation.
I did this with a machined titanium tube ,it was tight in the forks and stepped out to steerer tube width , after which it was epoxied into the fork...40,000kms no problems...it was a 3T fork with a very good internal fit in the tube.
Yeah. The key is to make sure the add-on is well sit in epoxy and bond stays solid. The result is pretty much as strong as a single straight tube.
I did this with a fork. I wanted an extra 5mm added to the fork. So I cut a 5mm piece off of a steerer of another "damaged" fork. The 5mm piece was of the same dimension as the steerer of the fork needing repaired. I then epoxied (using JB Weldit) the 5mm piece in. Then I used a really long expansion plug that is 80mm long (the one in Hambini video is about 25mm). I did this repair on an mtb fork and have been using it ever since. Absolutely solid. Now my extension was only 5mm, which means the stem was clamping on both the 5mm piece and the original steerer at the same time. However, I wouldn't recommd this method if you needed a much longer extention (eg: 40mm) where the stem could ONLY clamp to the 40mm extension piece and cannot clamp to any part of the original steerer.
Were talking carbon here!
I learn something new and profound in every video! Thumbs up.
Cutting steerer tubes is always a job I take loads of time over.
Measuring a good few times before I cut.
A good saw guide is recommended to cut the tube square.
A cheaper alternative is to use a couple of jubilee clips as your guide.
Oh and when you cut carbon wear a mask the dust is nasty stuff.
Enjoyed the video cheers.
Clamp two stems and cut between em. Mentioned on previous vidyo comments
Nice job. I did the same fix using a similar expanding plug. The only difference being I used JB Weld to glue it into the steel steerer tube on a MTB fork. Cheers :)
love it!!! p.s. cannondale doesnt maintain after market forks (even for warranty) with paint match.
That’s magic brilliant fix , that one’s going in the long term recall ! Wish all 5 year old’s smart as you 😁
That was a simple elegant solution, chapeau. I bought a fork off eBay but you have to get lucky.
That's actually one of the sketchiest fixes I've ever seen, introducing a weak spot and potential dimension tolerance problems right where the one of the most critical connections on the bike are.. On a steel steerer tube I maybe would give it a pass, but on carbon - no way.
As an owner of a very early GT Zascar Alu MTB, it had the first discbrakes I had seen by then. I then found a ligther Vision Kilo carbon frame which I replaced from the original, and the steerer became a little too short, but still mostly useable! I have lately found a Chinese extension part, like yours with a round top, making it able to get the handlebar moved further up. Finn. Denmark
how its going with the Chinese extension ? Any problem? Do you do trails?
@@guinieroo Well I haven't actually had a purpose to put them on my bike.. But my former alu frame had a little shorter head set mount/part so it is a little short for my new Carbon frame. Nothing serious, but I would like to get my handlebar and stem a little further up, in spite of a small increase in weight.
just bought a new fork for my madone SLR. I didn't cut it too short, rather i've just rapidly become an increasingly old bastard over the last 3 years or so. with that said i searched high and low for a solution like you actually manufactured since i only originally wanted to increase the height by 10mm. it was unlikely to be available in my case since the madone has a D-shape steerer tube but it would be great for other if you add that to your lineup.
This is the reason why I just recently on purpose cut my steerer too long :-) I don't want to find myself in the same situation few years down the road.
This channel is awesome. Great videos
That was a nice way of fixing it. Nice trick to have up the sleeve if it's ever needed.
The Delta brand steerer extender works perfectly well for aluminum and steel and is attached more securely than any stem on a threadless steerer. It’s only drawback is how it looks.
Delta is great and easily available. No easy solution for carbon steerers though - carbon is a lousy material for steerers, IMO.
hardcore engineering skills, I am flabbergasted by this rundown....
Excellent young man 👏🏾👏🏾. I also find its best using the long end when things seem deeper 🤔
I cut mine short and simply just bought a longer headset bung made by Deda which gives far more grip and therefore you can add more stem spacers.
With this fix... say goodbye to your steerer tube and your front teeth all in one simple failure. But, if you really want to do this kind of fix, don't.
Agreed with Hambini.Pipe cutter is the tool for it!
One of my 2 Cube bikes from 2008 came with a compression nut as you have shown at the beginning of the video. The odd thing is that people said about that particular type of steerer nut is for carbon forks, but that bike had an aluminium steerer tube (and that bike still has the same awesome fork).
The difference is in the diameter of those plugs.
Compression plugs work fine with aluminum steerers, as long as the diameter is correct (typically aluminum steer tube walls will be thinner than carbon counterparts) but it doesn't work the other way - you must not use a star-nut with a carbon steerer!
@@userkmunhwaock That was my assumption also. Now, I actually would group Al. and carbon on one side as "softer" and "easily scartchable" materials, while on the other side, Cromoly and titanium as harder materials. I would not use a star nut on anything else than steel and totally agree with the choice of compression nut for Al. parts, especially considering that the cones and sides (of the compression nut) are made of Al. themselves.
As for the diameter part, these expand quite a lot, but it's irrelevant, as diameters are well standardized. Actually, I would use these on any fork and do not understand why star nuts are still put on any bike costing more than $200; it's probably $0.25 more profit.
Measure twice,cut once, it's a solid repair is that, not too much 15mm, I'd be troubled by anymore than that 🤔👍
Take my money! 😂 we need this on the website to be ordered
Fantastic Powerpoint. Takes me back to the days of Graphics done on a Sinclair ZX SPECTRUM..... :-)
Many many many years ago I had this problem with a bike i bought used, but the tube was steel with a starnut. My solution of course in the end was to sell the frame and buy a new one, at the time i designed a similar device that would go interference-fit into the tube to extend it but it was too much of a hassle for me to do it
FYI, the fork is separate from the frame. Cool story about almost doing something.
@@wzpu3283 it was an odd old-ish frameset. The fork was carbon fibre with 1” threadless tube
I once bought a used bike on ebay that had a fork with (steel) steerer tube extended with a welded-on section. The thing was perfectly straight and true so I put it together with the spacers that raised the (old-time quill) stem up around 40 mm and had no issues. I figured even if the steerer tube somehow snapped in-two it was unlikely to fail without any warning. With carbon...I'm not so sure.
don't like ist, it's wonky. why not glue it in, so the load doesn't get tranferred through the knurled part of the expander alone?
Well Mr Hambini, i would say you haven't put enough ink in your pen this day lol. Not a big fan of this hack, i get it is a last resort (I think you didn't emphasis this enough). But I would highly recommend first, you get a new fork. Because you are only relying on the knurled expander plug and bearing pretension friction to prevent any moment movement from the point of the knurled section to the top of the stem clamping, which i would say the user has, the top clamp clamping point, on the new aluminium bung that has a slack fit. This could potentially wear the inteface between the knurled section and the inside of the carbon, or worst case, the handlebars could come off in your hand due to wear from movement when riding.
Also not a fan of those short plugs.
I made an aluminum part with central thread, using epoxy to glue it on the steerer tube.
I'd be slightly concerned about using this, the compression plug inside the steerer, should match the clamping area of the stem, as the plug is trying to 'stretch' the steerer, and the stem is trying to squash it, they support each other if they line up. Where the expander is now below the stem it's acting on an unsupported part of the steerer. Same thing happens if you have a load of spacers on top of the stem, which is why most manufacturers recommend a max of 5mm of spacers above.
Having said that, it's a small extension, so probably OK, but I'd still want some overlap between stem and clamping area of bung.
There’s no cause for concern with regards to clamping area as he’s using a machined aluminum extender. Aluminum steerers don’t use compression plugs. They use star fangled nuts. The sole purpose of the star fangled nut is to provide an anchor for the top cap bolt. The top cap is used to preload the headset bearings and remove play. It is only necessary for adjusting headset preload. Once that’s done, the cap/bolt/star nut are unnecessary. Carbon steerers use compression plugs instead of star nuts. But they serve the same main purpose. To provide an anchor for the top cap assembly when adjusting preload. SOME carbon steerers are not strong enough to withstand the the clamping forces of overtorqued stem bolts. And that is where compression plugs provide a secondary benefit. They do not stretch the steerer tube. They do provide additional support to avoid crushing the carbon fiber tube in cases of overtorqued stem bolts. This is why some manufacturers recommend specific compression plug designs and placement. Most manufacturers actually recommend a MINIMUM (Not max) of a 5mm spacer above the stem. Manufacturers do have a recommendation for max spacer height but that is for BELOW the stem.
This is only superficially true. The plug is in fact not an inherent design element of the headset. Just think about the sheering forces occurring when you pull the handlebar. At the places where the stem is going through the frame there aren't any internal expanders present. The forces during riding and pulling the handlebar which act's as a lever are huge compared to anything this kind of plug does to the stem. So if the stem can't handle almost arbitrary placement, the whole fork is not sufficiently strong in the first place. Squashing something twice will not help its internal structural integrity.
What's better? Using a stem pointing up, or raising a few spacers?
Mechanically a stem pointing up is theoretically better. However since all parts at all angles and heights are designed to manage the loads anyway it's rather irrelevant. Decide based on aesthetics.
Joe's carbon repair in Watsonville CA fixed my fork for $200 after my mechanic cut my steertube too short, after taking a bong hit.
Nice engineering work (at least I guess it is, I'm not an engineer)
However I would sell the fork to someone running a smaller frame size and just get a new fork..or measure twice in the first place
Calling any part of this job "engineering" is hilarious to me.
Excellent stuff my man!!!👌👏
As Tommy Walsh used to say: "Measure Twice, Cut once"
I was told this time and time again as an apprentice Toolmaker, now I tell every apprentice. It’s the only way as I’m sure Hambini and his hairdresser would agree.😂
My left ear learnt a lot!
Have you seen or do you have any opinion on the Velobike steerer extenders they make? They say they're good for aluminium or carbon steerers.
The plugs are longer too. So, they will be better than this
I’m quite impressed this is a neat fix. How much torque did you apply to the bolt that fits down into the original compression plug? I normally don’t go more than 5-6 nm to avoid stressing the steerer tube walls from the inside when fitting a compression plug.
Hello Bambini!
awesome fix
Ideally that machined part should be bonded into the steerer tube so as to eliminate any small chance of that piece turning and also the adhesive would fill that 2mm difference between the inner diameter of the steerer tube and the outer diameter of the machined piece eliminating any crush on the carbon part of the steerer. As is the compression part of the compression plug is serving a purpose by holding things in place, but it is not doing it's main job of preventing steerer crush as it is now under where the stem is clamping the steerer. Granted there is only 2mm difference but that's still enough to crush via over tightening or crash related forces.
Crush is only when the external force exceeds the internal force. I always use the same torques on the plug and the clamp to reduce risk compression deformation of the steerer.
Surprised it wasn't bonded as well. Can't see any need to be removable unless I'm missing something?
That’s not a headset Hambo it’s a steerer plug! There is a kiwi company,who’s name escapes me, that does a high quality version of this to extend head tubes by up to maybe 35 mm.
velobike
Velobike, they specialise in track components 😊
The only issue is you did you not line up the expanding pieces from the expansion plug so they are equal on all sides (same gaps). I made a boring 20 minute video explaining how even pro bike mechanics are installing these expansion plugs wrong and also the wrong length. Basically you want the length to go down pass the head set bearing, then you want the expansion pieces do go into the the steerer tube already a bit expanded so this way they go in pregapped the same on all sides, since there are 3 pieces with 3 gaps, one gap goes directly to the front of the bike, the side gaps will now face back angled, the faces will face the handlebars which is important in order to protect those ares from the handlebar hand movement forces. Great video and a good fix!
Why do people cut steerer tubes unnecessarily close / short. I leave mine a bit longer and just add a couple of spacers under the top cap. That way when you come to move the fork on (between frames / or selling) you always have a bit more stem to play with. Simple really.
Exactly. And IMO it actually looks better
Beautifully simples.. 🙏
I'd want the insert to closely match the internal contour of the carbon stem to prevent the stem collapsing from the stem's clamping load. This is particularly important when you consider the competence of your customer. If they can't measure and cut a stem, they're not going to understand torque wrenches either.
Those amazon sold extenders are often listed as steerer extenders for MTB....makes sense as the steerers are mostly alloy. I actually like the idea of this extender Hambini has fabricated as you're that plug further into the steerer and then clamping into the alloy extension which I prefer
Are they going to work on a carbon tube?
Stem extender will do.
I made an additional sleeve, so it can clamp onto the carbon bit.
The HELLOOOOOOOOOO just freaked my kid out. I did have the volume at max tbf
I bought a bike brand new with one of those expanders installed. The shop that assembled the bike cut the steerer too short. The bike is meant to be used off road. I havent noticed any play but the stem is on the extender. It’s is a steel frame and fork ( gorilla monsoon). Should i order a new fork or is this a ok solution ?
Do you recommend s;omething like this for a mountain bike?
I use the Zipp Sprint SL stem and you can’t use a spacer under the stem cap because it’s not round. Hasn’t failed yet thank goodness.
this one is fantastic!!
You should send one of these fix to GC Performance. He has one of those carbon fork steerer hanging on his shop that he cut too short.
He's not going to do that on a customer's bike. What Hambini made is already available by various manufacturers. It isn't a new idea.
Love the video, great idea bud!
Do you think this method would work on a downhill MTB fork, have you ever tried it on a mountain bike?
Thanks!
@RollinRat Well I do appreciate your input, and the fact that you seem to come from a genuine place if caring, so thank you.
I actually have a full carbon frame on one of my DH bikes and it's pretty strong. And I also have a carbon Renthal bar too... I prefer aluminum though because I don't like the take of stem and teeth.
I've been riding DH for almost 25 years now. I was riding yesterday, and every weekend this season. I've broken a few bones and snapped a few frames, all to say I've made mistakes of my own. I've also raced with a 1999 Boxxer fork with a cracked brake arch, hit drops on a cracked GT LOBO and still send big jumps and drops on my cracked Santa Cruz Super 8. That's all to demonstrate my level of stupidity. Clearly, I'm not the brightest.
But this thing is pretty cool, and it seems like it could work on my Avalanche front fork. Downhill forks are not as reliant on steerer tube strength as single crowns because the dual crowns can hold the steerer in place. And I can use my Da Bomb head lock to sandwich everything in place thru the steerer tube without even using a headset star nut.
Can Hambini fix other things that are too short, as well?
I often use the long end of it. Especially with my ball head allen wrench (get your mind outta the gutter)
Hello, how and where can we purchase this product? Thank you.
Any way I can get my hands on one of those extenders without taking the time to learn to machine it myself?
If you contact me on support@hambini.com I can probably machine you one up.
Did he cut steerer tube under spacers and then realized stem goes flush on top of head tube?
Steerer tube is never too short! Slam the stem!
Would this work for a set of downhill MTB forks?
Heyo Hambini, where did you get your drawer unit from (as seen when you're doing ppt.)
To my mind, doing any of this is fraught with danger, which really hambini why subject yourself to it. The liability is too great. Although the plug extends under the stem enough for its grip, the plug should really be extended even further to a decent amount below the upper headset bearing, and the expander surface should be much more. To each his own, but bottom line if you cut it too short, get a new one, paint color regardless, just roll with it using a straight major color from the current paint scheme.
Absolutely agree. The plug seems far too short and likely creates a new stress point in the steerer tube - lateral forces would be basically concentrated where the plug ends within the steerer tube and only an inch or so of the carbon tube taking it all. Zoinks!
Alternatively make an aluminum insert/extender that is epoxy bonded into the fork with lots of overlap inside the carbon fork for max strength. No expander used. It is a one off repair that makes the fork a fixed (longer) length. It adds a little weight but no concerns about strength or where the stem clamps.
Any chance you could sell these, maybe in varying lengths? I had this issue last winter, and while looking at the expander wedge I though of basically what you did here, although I was gonna go about simply adding something that would look like a headset spacer between the seperating pieces to give it a bit of length I need, but I havent been able to find anything with the correct diameter, and I dont have access to any machine shop or anything.
What he made is available for sale by various companies. VeloBike makes one. The expanders are longer on the commercially available ones and so actually better.
@@DaveCM I ended up ordering the velobike one, I just thought it was too much $ for what it is. Doesn't help that its for a frameset that I'm more likely just going to sell rather than ride (didn't want to sell it in the state it was like someone did to me). I guess I will just have to ask an extra $100 to cover the piece!
Do you patent these solutions before posting on RUclips?
need to buy this!!! Plz let me know how I can buy this
Can we get and update? Did your buddy die on a descent?
Super powerpoint!! I wish that I could do.. Rgr
Hambini, in all Cannondale manuals for caadx and caad bikes, it is forbidden to put a spacer above the stem, for safety reasons...
really, do send a link
@@Hambini Warning on page 10 of the Synapse Manual. Looks like the top cap has a built in spacer though. www.cannondale.com/-/media/files/manual-uploads/manuals/oms%20cd%20bk%20rd%20synapse%20disc%20en%20r1%20134911.pdf
For instance:
www.cannondale.com/-/media/files/manual-uploads/manuals/2011_webOMS_127398_SuperX_EN.pdf
Page 10
"Assemble the fork, headset, spacers, and stem without tightening the stem bolts onto the head tube. When
the system is assembled, the carbon steerer tube should be 2-3 mm below the top stem. All spacers must be
located below the stem and within the maximum stack height as shown. No spacers may be used above the stem."
I can go on, but I think my point is pretty clear :)
@@vromaka Cannondale's are a bit unusual though. They use this SI compression assembly where the top cap threads onto the expander and you install both at the same time, plus the top cap has an outer sleeve that reinforces the steerer tube where it is clamped by the stem bolt. So you can't put a spacer under the top cap anyway. In any case I wanted a custom top cap so replaced the Cannondale assembly with a much longer pro compression plug which provides much better support to the steerer tube. That allowed me to use my custom top cap and as I have not cut my steerer yet have a couple spacers under the top cap with no issue.
That's a clever solution. What would you think about just making a solid plug and epoxying into the steerer tube?
so it has to be tight fit/ press fit?
@@NeoPayneHK Slip fit
I've seen a study done into reinforcing steerer tubes, the issue with solid insert is what people don't see is that under braking the steerer tube actually bows a little, so if you then add a solid metal insert the bottom edge acts as a stress raiser and move the point it bows at lower down the steerer, this could lead to premature failure, the out come of the tests was that Cervelo's method of bonding a tube in for a star flange nut was okay as long as it's not to long, and Campagnolo extra long expander were the best way add strength to the steerer tubes.
How do we know if the pen is working?
Nice fix. So are you now expanding your product range? 😉
I've been looking at wheel hubs for a while, that might be the next one.
@@Hambini ooo interesting. "Hubini"
I am really not sure what an AL insert could not turned on a lathe to join another piece of AL or carbon that would simply extend the fork
Hi do you stock these parts please
I don't but you can get the drawings and a link to the bits from the linked webpage. It's in the description
I'm never sure if you're talking about the fork or the fo/uck?
This make sense 👍
Compression plugs , in general..are 2 short .. size matters .
I’m bald and don’t go to a hairdresser , any tips on hooking up with one ?
Excellent…
Wont the extension piece spin relative to the fork tube?
If im doing that, id add some notch/keys to the bottom piece and extension piece. Just a peace of mind.
Pretty much like those threaded fork to threadless fork stem adapters.
Waiting for comments from the so called professional bike mechanics.
The pen is not working?
My hero! #Engineer4Life
Sketchy as frig… if the lower bolt on the stem fails you are hitting the deck.
Just buy a new fork.
velobike already does one
My hairdresser has advised me to get one of these...
I guess time will tell of the reliability of this repair.
But it is cheaper than a new fork... long as it doesn't fail during a high speed decent.
Hhhheeeellloooo im a Swedish fan!
This guy is hilarious
Which forker cut that too short!!?? ;-)
Clever👍🏾
Why not make a machined alloy piece as you did but make the insertable part say 3 inches long or longer, then bond it in permanently? Poor steerer concentricity wouldn’t matter, nor would a flush cut carbon end, just design the piece symmetrical and with the thicker part oversized, then when the resin cures, set it up in a lath and machine the alum even with the carbon. Let it setup in a jig to keep it as straight as possible. The alloy piece can include threading for the pretensioning bolt. If the carbon is compatible with the alum alloy. I know they do make carbon bladed forks on alloy crowns and steerers. If there is any concern about the bond breaking, just steel pin the two together in a couple of locations.
I need to extent fork but not because I cannot mount stem but because I want it higher, original is cut too aggressively for my liking. I guess I need to sue some extension from amazon