Probably so, but it depends on frame tolerances. Threaded bb shells have to be about round and proper size, or the tap will break off. That's a pretty low bar, but it's something.@@twatts4436
Very very informative. Clearly explained. Finally thank you for getting to the point and not bamboozling us with marketing bullshit. As an engineer (materials, metals) i appreciated it.
My oldest bike, long since gone was a 501 framed Raleigh from the early 90s. The bottom bracket became loose so i undid it competely, and found the ball bearings and races pitted. I bought new(loose) bearings and packed in castrol general purpose motor grease, adjusted the bb to a fine tolerance and proceeded to 200 im audax rides and 25 minute sporting 10 on that 26 lb thing. So simple to maintain. I agree that the cycle industry seems to have made bbs to too larger variety. Keep up the good work mapdec
Threaded BSA just works so well. Specialized realised the error of their ways with creakyfit and Santa Cruz with minor exceptions have always stood by it. No other BB type needed.
Great video, but a few quibbles :) That Swinnerton is of course brazed not welded (you can't weld 531) and the BB shell is a single casting. Second the real compromise is between Q factor, CS length, tyre width and tyre diameter. The CS has to find a path around the tyre to the BB shell without hitting the cranks or the chainrings. That is the real challenge. It doesn't really matter what BB shell you're attaching it to (whether it's 68mm or 73mm wide or whatever the diameter). Third, an ovalized CS doesn't have any more surface area to weld to-- it's the same perimeter, you just squashed it. In Damon Rinard's FEA (for what it's worth) round/oval/round CS were better for torsional stiffness than ones that were oval at the end. I don't know why the trend for oval. No real advantage but they are easier to weld on because you can fit your TIG torch down the middle. However I have made a number of TIG frames with ROR CS and 68mm shells and it can certainly be done. Fourth, everything gets *much* easier if you just use 650B or 26" if you want fat tyres :) But these days people seem to want 700c, really wide, and short CS hence the creative solutions like dropped CS as you said. So in summary I'm not sure all this justifies all the BB standards. There was always a use case for 68mm and 73mm and most BBs were compatible with either. But not sure we needed BB30, PF30 and all that for the CS length business. Cannondale invented BB30 I think because they wanted to use aluminium axles, which need to have larger diameters. PF30 was just the same thing but with sloppier tolerances. But regardless of BB standards it's an interesting discussion about that four way compromise between Q, tyre width, tyre diameter and CS length, and that is certainly one of the fiddler aspects of framebuilding. Another thing people do to effectively reduce the CS length (on steel frames) is curve the seat tube backwards. Finally CS length is conventionally measured down the middle, i.e from centre of BB to centre of rear axle. But it doesn't make much difference. I think on that aluminium frame the stays had probably just been squashed a bit rather than hydroformed, and of course people have been dimpling chainstays on steel bikes since forever. That can allow you to squeeze a little bit of a bigger tyre in.
This wasn’t a video about joining metals, and I wasn’t going to make it longer to start explaining terminology. Some of your other facts were quite wrong. For example PF30 helped solve the tolerance isssue of BB30. BB30 was only on metal frames and the bearing pressed directly into the shell. PF30 allowed the use of a bearing carrier to help. Cannondale still messed it up, but the thought was there.
All the way through this video I was thinking "if you want to keep the chain stays short just fit smaller diameter wheels!" I think it's crazy to go to such lengths to accommodate 700c wheels, and for what gain over 650Bs?
@@nickwinn7812 that is already done, and has been done for at least 40 years when cannondale had a 24"/26" mountain bike. can't recall which was front/rear. when disc brakes came along, changing wheel size became less of an issue (other than say bb height) and could also accommodate larger variety of tire sizes. nothing to do with bb width. 73mm were used back in the 80's and of course much wider bb's for non-road bikes. about the only time bb is a major factor is with e-bikes and their bb mounted motor.
@@nickwinn7812 I think it started with "29er" mountain bikes. The big wheels help you to ride over everything like a monster truck. But the actual rolling diameter of a 26" wheel with a fat tyre is about the same as a 700c with a traditional narrow tyre. And these are gravel bikes we're mostly talking about. So yes I don't think we need such big wheels.
Great video. I always appreciate a practical explanation/comparison of various bicycle geometries, and what it means to the rider. I look forward to more of these types of videos!
Yes! information above and beyond. I am always curious why geometries are what they are it's always more than "handling" There are always compromises made that manufacturers won't tell you about.
Nice to hear Brucie's name mentioned. He built frames for both myself and my wife. Mine was sometime in the late 1980s - £440 for frame and *full* Shimano 105 12 speed groupset with SIS shifters! My wife still has her frame, now as a singlespeed.
A very, very informative video that addresses the compromises necessary to accommodate wider tyres. Learned a lot from your analysis, but still a little uncertain re the dropped chain side chainstay. Big distortion for minimal gain? Thanks and well done.
This was really good! It helped me enormously. I'm currently on a 2012 Ribble Stealth (essentially the same as the De Rosa of the same period) and I'll be finally upgrading in the next year, but I've been a bit lost. I love my current bike (obviously after nearly 13 years...), but I started to realise that I do solo endurance rides almost exclusively. Do I need nimble handling? I've got to say, "No, not at all". Even though a low and long geometry suits my body (short legs, long body, fairly decent flexibility), it's becoming clear that a race bike is not best suited for the riding I'm doing. This gives me a lot more understanding of what I'm trying to shoot for!
T47, internal bearing, seems to be a good idea as an improvement of the good old BSA since it has a wider area for the chainstays and threading instead of unreliable press fit. By the way , thank you .The best explanation of my understanding of " The history of bottombrackets " ,witch have took years to summary.
I had a old Mondia cyclocross bike that had a bizarre bottom bracket threading and axle length... M35 X 1.0 mm threads but the drive side was left handed, non drive right handed..And weird inside BB cup size.. nothing fit.. loose packed bearings and hope for the best...
@@Mapdec Paul Exactly so the industry has flogged the BB issue to death for well over a decade now its the turn of integrated headsets, more fashion in this than ladies designer shoes 🤣 Clearly the future is already behind us 🚴♂
@@Mapdec my daughter is into MTB XCO. Have been looking to progress her onto a full suspension MTB. I've settled for a Trek Super caliber SLR 9.8 XT. It has an integrated bar/stem but the hoses enter the frame behind the head tube and not through the headset. That was one of my reasons for choosing it.This will make it easier for maintenance but, also importantly, servicing will be cheaper. This push for change by manufacturers doesn't always lead to better outcomes for customers.
Most British custom fames weren't ever welded! BMX and then mountain bikes brought TIG welding to the high-end bike industry, and it didn't get to road bikes until at least the mid-1990s, and even then British and Italian builders didn't take to it. In fact, even the best custom British MTB frames (Overbury's, Roberts, Yates, etc.) were never welded. Pegoretti and Raleigh (yes, Raleigh made pro-quality frames back then!) were some of the first road brands to use TIG welding, but they were outliers. Brazing, which is very different to welding, is how the vast majority of steel road frames were constructed until mass-produced imported aluminium frames took over from local custom steel. And, that old Trek OCLV would have seen 23mm tyres maximum. Anything wider for a serious road bike is very recent. I left the industry in 2016, and 25mm or wider tyres on a road-race bike was still a very strange idea back then. In fact, the carbon frame brand that I worked for made TT and Tri frames that would only take a 23mm tyre. A 25 (or fatter 23s from Michelin and Vittoria) would foul the seat tube cut out! 23mm Conti clinchers - or 22mm tubs - was where it was at for serious road and TT bikes. There has been a rapid demise of the high-end bicycle. What was once an elegant and beatifully simple device got caught up in a tech arms race and marketing BS. Unless it's a serious race bike, for actually racing on, all this tech and multiple standards for BB, hubs and headset is total nonsense and is killing cycling. Electronics likewise. Internal hydraulic lines likewise. odd-section seat posts likewise. One piece cockpits likewise. Tubeless likewise. We had more fun in the 1990s, 2000s and 2010s with much, much less. Club road cycling was affordable and accessible. MTB was a blast and didn't involve costly/complex suspension bikes or packing up and trekking off to distant trail centres. Bikes could be worked on at home, easily. Fit was a doddle to adjust for. Stuff lasted. Spares were standardised and simple to source. New bikes are ugly, heavy, unreliable, plastic, foreign (in every sense!), complex, fragile, tricky to work on, and very, very, very, very, very expensive. Tomorrow's landfill. Something has gone seriously wrong.
@@Mapdec There were no bad bits in my past. Having worked for years for a top-end carbon frame brand, I now ride only steel fixed on the road and steel, rigid, singlespeed MTB. You're right, nobody stops me!!! Steel is the real deal, Neil.
You just summed up what I've been feeling about "modern" bikes for the last decade. I think one of the problems is that many people think that if a thing is more high tech, it is automatically better, and even worse, will somehow give them a performance boost.
@@nickwinn7812 A big part of my job in the industry was to make supposedly clever people buy stuff - that they didn't need, wasn't suited to the use they would put it too, and cost more than they could really afford. It wasn't difficult, and "victims of marketing" is how we described them amongst ourselves in the office. Bexit, Trump 2.0, and the purchase of top end road bikes by cyclists who will never race race are all examples of consumers/voters (same thing) willingly acting directly against their own interests. It would seem that consumers are irrational and compulsive, and will fall for the marketing hype every time. Kerr, ching!!!
I don't feel great about running SRAM Dub in a PF86. (Giant Revolt). I've never had an issue to date, and I went with a Rotor dual row ball bearing upgrade - but still.
In the BMX industry, standardisation has ruled supreme. There was a brief period (2002-2004) when screw-in 'Euro' BBs arrived. And a few manufacturers experimented with smaller diameter shells to save weight. But these innovations never took root and an industry standard emerged. Why? I think it is because the consumer demands standardisation for the sake of customisation. Riders have different needs, and they want to be able to piece together parts from different companies to meet them. In road and MTB, consumers are used to buying a complete bike and changing very little other than perhaps tyres and the bar tape.
@@Mapdec There are two crank axle sizes: 19mm and 22mm. But the outer diameter of the press fit bearings are always the same, and there are no threaded options anymore. The parts companies' bottom brackets are identical aside from the logos on the spacers.
Do short chainstays really help the handling that much? It makes such a tiny percentage of the total wheelbase, and I've been on some good-handling tandems, which have much longer effective chainstays. Thanks!
Depends on what handling characteristics you are aiming for. It’s quite a large proportion of wheelbase, but where weight is balanced within that, yes, has many more variables.
Great video, really opened my eyes to some of the "why"s, thank you Mapdec! Question - how much impact does frame size have on chainstay length? Is it enough to be able to fit wider tyres in larger frame sizes? Or alternatively - is the shorter chainstay on a smaller frame size enough to make it worth using a smaller frame if you're after a bike which feels more agile?
Isn't at least part of the reason for increased BB diameter, the requirement for a large surface area to bond the aluminium parts to the composite parts?
I think the real reason of having so much BB's is the stupidity of manufacturers and the lack of awareness of consumers. The bike industry has forgotten what unification is and that a bicycle was originally invented as something reliable, and not to be replaced with the frequency of buying a new iPhone. See? We made carbon wheels! But now your rim brakes don't work well in the rain? (everyone rides in the rain at top speed, huh?). Buy disc brakes, but you'll have to buy a new frame, oops. And then again: are you riding QR? Because of the disc brake, your axle can slip out of the dropout!, thru axles are safe, but you'll have to buy a new frame, oops. But this is not enough, so each manufacturer decided to invent their own bottom bracket. And other "innovations" that you wont find it a model couple years newer. So they produce garbage that in 20 years you will find in the garage and will not be able to get parts for it, because the experiment with the bottom bracket and unique headset/seatpost shape/fork was unsuccessful and no one makes parts for it anymore. (You already can see some frames without fork or seatpost for cheap just because its hard to find part) But all of those brands will claim that they're green and support recycling, of course.
I don't think in the time of the Trek oclv anyone was riding 25 or even 28 mm wide tyres as they were not readily available as race tyres. Anything over 23 mm would have been hard to find. Trek were probably looking for a longer wheelbase without slackening the head angle too much.
Is there any production (as opposed to custom) bike that has a chainstay of 410 mm or so that will accomodate a 700C X28mm and a large volume 650B tire? I like the idea of having an agile road bike, and am willing to go down a tire size to be able to use the same bike with a large volume tire, for gravel riding.
Why is there so much effort to keep the chain stays short? I feel like this is the last hold out of the “feels fast” era. 110 psi feels fast but isn’t. Short chain stays feel fast. Are they? Is there any measurable performance benefit?
Subject of a different video. In fact probably many videos. The effect is generally no different to a car. The main difference being the cone of movement of the rider.
@@Mapdec hmmm. I’m not sure I understand how that translates to a performance benefit. I think I would prefer a slightly longer chain stay in exchange for a more reliable (or consistent) bottom bracket standard.
@@and2244rew nothing wrong with BB386 or T47. Anyway. Depends how you measure performance. Straight line speed a long chainstay and long wheelbase would be better for stability. For fast corners, manoeuvring through a peloton, a shorter wheelbase would be easier to maintain speed. Most people don’t race, but like the fun of a race bike. Same with cars and motorbikes. Sports cars rarely see a track and only cruise up and down motorways. It’s crazy, but we all enjoy it 🤷♂️
Really odd decision. I suspect driven by the current kick back we are seeing against pressfit. The big media channels usually champion BSA. IMO it should have stayed T47i. I can see Colnago are only really interested in campy or Shimano cranks so they don’t need the bigger bearings, but even BB86 would have been a more obvious choice. Seems odd to make a very aero bike and not smooth the air flow round the BB and just plonk two outboard bearings there. BB86 would also have given more scope on the chainstay design. I haven’t seen any reviewer question it.
Didn't 11 speed drivetrain specify a 425 mm chainstay length for acceptable shifting? Think I remember reading this a few years ago. The range of angles for 11 and 12 speed can be quite large on a 400 mm chainstay and lead to poor shifting.
Depends. 405mm is general minimum (bit of rounding in this vid) 1x and large chainrings can be shorter. 395 I think. Dub wide is defo 415. Fallen foul of that one.
No bikes are a 400mm chainstay. The minimum is length allowed by Shimano is 405mm. The desired advantage for short chainstays is placebo at best, most people wouldn’t feel the difference between 405 and 420 but the longer will have a much better shifting and chainline due to arc tan etc etc. Also t47 internal, 386 evo have no extra width benefits over pf86. Pf86 gives you clearance for 34/35mm measured tyres with ample chainstay thickness for stiffness…
My Pelizzoli pista frame has 390mm stays (yeees, pista is a bit different), but still a bicycle. For both authors of the comment and channel I wish you more time to spend with different steel bikes.
youtube.com/@PeakTorque - maybe you could show the tradeoffs in CAD. Especially with the shapes that can be made in carbon, I'm not getting why we can't have a bit bigger diameter BBs to help bearings actually last and have thread shoulders with more make-up face area.
I don’t know why you’re so stuck on chainstays. I don’t think anyone could reliably tell the difference between 400mm vs 410mm. Also even if a 400mm chainstay was by some measure ideal for a size 54, that doesn’t mean that will produce the best handling characteristics on a size 58. Years ago I bought this weird 60s Japanese frame and built it up with modest parts. I quickly fell in love with its handling and opted to ride it more than any of my other bikes, despite it being heavy and having ancient technology. That bike had 460mm chainstays on a road bike designed for thin 25mm tires! That’s longer than basically any gravel bike on the market and is firmly in hardtail territory at least! This weird geometry made steep climbing feel incredible stable, and descents feel so confident. The steering was still as quick and responsive with a high trail fork. It was the quirkiest frame that was probably only designed that way because the Japanese manufacturer was out-of-touch with what popular European Manufacturers were producing at the time. It even has the strangest 70mm wide BSA threaded bottom bracket shell!
Stuck. I made one 10min video out of collection of 600 odd, and this one mostly focused on BB development and why tyre width and Chain stay length played factor in the development of all the standards we have today. I’m glad you found it entertaining
Strange that none of the creators of the various bottom bracket standards said anything about chainstay length when unleashing their creations and instead touted things like weight and stiffness. it's almost like frame geometry has nothing to do with the bottom bracket standard
@@Mapdec I'm becoming less convinced you know what a bottom bracket is or does, not even sure you know what cannondale Ai is either if you think that supports what you said
@@Mapdec I think you're probably underqualified to work assembling bikes in halfords, seriously the simple existence of bottom bracket adapters shows just how dishonest a video this is
According to Cognitive Market Research, The Global Gravel Road Bike market is projected to reach a size of 519.2 million in 2023, with a compound annual growth rate (CAGR) of 13.5% anticipated from 2023 to 2030.
Upper end MTB are indecently expensive which is a killer for sales. Trend has been to gravity events so the bikes are more expensive. Good XC trails giving way to more enduro trails - can be more fun but too hard for average beginner punter. Imagine if, perhaps because of race coverage of Pog, road events all became long hard climbs. What would that do to the "fun" element for the average road rider?
Taking 0.5cm (or less!) off a seat stay length is surely not going to be a gamechanger for agility on a bike?! There is definitely a degree of cost saving for manufacturers (in just needing a hole for press fit rather than a threaded shell) and also wanting to create new proprietary BBs people also had to buy/replace rather than standard BSA ones anyone can manufacture...
I hope the rest of the video was interesting, but "welded" instead of brazed and "millimetres" instead of centimetres is so annoying that I stopped watching.
Ah. You missed out. It’s not a video to explain how metal is joined. Everyone knows that welding joins metal. Brazing is term that didn’t need explaining for this short video.
@@Mapdec Sure and yesterday did you "hammer" some screws into your wall? The other day did I "hammer" in the bolt that holds on my classic tapered crank arm onto my BSA crankset? Personally I'd use the correct verb.
Nice and insightfull video! There is only one thing that gives me a headache: Please stick to static shots! And please don't do shorter cuts than 3 seconds. I almost stopped watching in the middle of the video, because all the movement and some VERY short cuts made it hard to concentrate on the content.
@@Mapdec Finding someone in your area (or even remote) to edit your videos shouldn’t be too expensive. If that’s not feasible, there are some basic rules that you can learn quickly, some of them I tried to outline above. Some will even save you time, like your camera person only hitting the record button once the camera angle is right and only move the camera away after they stopped recording will be a huge time saver when editing (a tripod could help). So you can decide if you throw money or time in. Or you find a film school intern, but that often ends up in more time spent in educating them, even with professionals you need to communicate and things can go wrong. So as always there is no silver bullet.
Dude completely glosses over the role of the CURVED SEAT TUBE. If you're willing to curve the seat tube like in the final bike, you could probably go back to a BSA BB 🙄
@@Mapdec Well if manufacturers had committed to curving the seat tube when wider tires started being a thing, maybe DUB cranks wouldn't need to exist and we'd all just have cranks with a 24mm spindle.
This explains why we had ever changing bottom brackets over time. But there's still a question mark against why there's so many right now,on current bikes.
Consumer demand. We now face the problem were people are demanding BSA. We also have Shimano driving the Bb86 for OEM. Really there should be 3 standards. BB386evo for race carbon, T47i for MTB and Non race carbon, and T47 for metal frames.
@@Mapdec Paul and we all know why that is ……….an attempt by carbon frame manufacturers to side step issues created by an inability / commercial unwillingness to make two round holes opposite each other. Shame as executed well …….no issues………..but that’s the story of the ‘modern’ bike industry isn’t it ? 🤷
No, no. There was a huge mistake at the beginning-not all steel racing frames could fit 23mm tires only. Please, stop making it look as "typical example" of vintage bike. I worked in a bicycle shop that sells only vintage bicycles, and "23 only" is more the exception than the rule. I personally have two top-line bikes: a 1978 time trial custom-made Woodrup, with a max tire size of 30mm, and a 1990s F. Moser road bike, with clearance about 30-32mm (measured now chainstay - 40.2cm with 28mm tires installed). Yes, there are some bikes with (for example of the reason) unicrown lugless fork that can fit 23 max, some with Colombus Gilca tubing and fancy Chinelli BB lug - also 23max, but this is only 2 cases that my friends currently have. It mostly about late 80-90-s when bicycles became very short and tight (50-60-70-s were longer wheelbase because of not very smooth roads as one of the reasons). Also length of the chainstays depends on BB drop and ST angle. (With higher BB and steeper ST angle you can make stays shorter)
@@Mapdec For me, as a person who appears alone at rides on a steel bike among carbon, this myth is a rather sensitive "point". But in any case, I think that your conclusion in the end about the problems caused by the narrowness of the BSA and ITA bottom brackets is not very correct. Firstly, because there are a huge number of top of the line bikes with such bottom brackets and at the same time quite good clearance for tires (up to 32 mm for vintage ones) and short chainstays (shorter than 41cm). Literally two examples are in my room. Secondly, lugs are not always necessary - if you use welding or fillet brazing - you can achieve even greater capacity by the width of the tire. Also, as a "cheat" you can use a "yoke" connected to the BB (something like a plate, to make it narrow or even to go down a bit) and only after it there is a tube.
It's a bit nit picky, but I had the same thought. My '74 Raleigh International can handle 32mm tires, even though it was sold with tubulars. As noted, the 80's were all about tight clearances, so my mid-80's Hetchins has short reach brakes with the pads at the top of the slot. I've got 25mm tires on it now, but they are almost touching the brakes. One detail in the video that struck me as wrong was the suggestion that the USPS Trek OCLV frame was intended to take 25mm tires. Racers were still using tubulars then, and folks were still pumping their 23mm tires up until rock hard. Unless someone has a catalog saying that they were sold with 25mm tires, I'd contend that the goal was 23mm. I'd say that the time when BB standards were fairly standardized was when Campagnolo NR and SR were the top of the line. Tech was a bit stagnant then, and no one was changing stuff just to change it. That came later, when the manufacturers were trying to show that they had the lightest and stiffest design. Mountain bikes probably had something to do with it too? The larger tube sizes for the new frame materials certainly were a factor.
Clearly there are exceptions but think it’s fair to acknowledge that the vast majority of road bikes from that era had chainstay clearance for 23mm, 25mm max.
@@kevinfrost1579 Steel bikes? My two bikes with the tightest clearances at the fork crown and brake bridge (barely able to pass a 25mm tire) have 32mm between the chainstays. These are a '82 Raleigh Team and the mid-80's Hetchins. These are Reynolds tubed bikes, so fairly conventional. My International, which has huge clearances at the brakes, also has 32mm between the chainstays. That was pretty typical.
Because bikes are designed by engineers who have never ridden, sold, assembled or repaired a bike. Every Giant gravel bike I have ever seen had water in the internal cables which needed to be replaced $90. Horrible idea.
unfortunately, he made too many mistakes in parts about BSA/ITA bb's and steel frames. And not mentioning BB drop/ST andgle in talk about stays length (especially comparing them by 5-10mm difference) is wrong
![Noob To Max With DRAGON REWORK In Blox Fruits [FULL MOVIE]](http://i.ytimg.com/vi/LnBMOinoOvA/mqdefault.jpg)
Steel bikes with lugs were brazed, not welded.
repeatedly.
O.o How you managed to cram so much info in 10 minutes is simply magic and mastery 👍
The guy is brilliant! It was all completely understandable as well.
Good explanation of a topic I never bothered to try and understand, despite having ridden bikes for 40+ years.
I'm doing my part by not buying anything other than BSA standard!
PF86 works pretty well and is easy to work on. Issue is frame manufacturers have rubbish tolerances.
Surely that locks you out of certain disciplines?
@@twatts4436 BB386 EVO should be the standard! end of discussion :P
Probably so, but it depends on frame tolerances. Threaded bb shells have to be about round and proper size, or the tap will break off. That's a pretty low bar, but it's something.@@twatts4436
You sir are excellent at your craft! Thanks for producing such terrific educational content!
Very very informative. Clearly explained. Finally thank you for getting to the point and not bamboozling us with marketing bullshit. As an engineer (materials, metals) i appreciated it.
Your videos are always so informative. Thanks.
And the nicest looking of the lot is the Swinnerton!
Steve will be very happy to read this 😍
My first “real” bike was a Swinnerton cast off - great frame and very well made.
@@Mapdec Yep!
Excellent explanation of the issues around BB's and chain stays. Swinnerton looks great. Thank you.
My oldest bike, long since gone was a 501 framed Raleigh from the early 90s. The bottom bracket became loose so i undid it competely, and found the ball bearings and races pitted. I bought new(loose) bearings and packed in castrol general purpose motor grease, adjusted the bb to a fine tolerance and proceeded to 200 im audax rides and 25 minute sporting 10 on that 26 lb thing. So simple to maintain. I agree that the cycle industry seems to have made bbs to too larger variety. Keep up the good work mapdec
Finally! A proper explanation for all the BB standards and the funky chainstays. Now I know :)
Threaded BSA just works so well. Specialized realised the error of their ways with creakyfit and Santa Cruz with minor exceptions have always stood by it. No other BB type needed.
Except for when you have dub or 30 cranks.
There's no denying it's stood the test of time. Likewise steel frames!
Great video, but a few quibbles :) That Swinnerton is of course brazed not welded (you can't weld 531) and the BB shell is a single casting. Second the real compromise is between Q factor, CS length, tyre width and tyre diameter. The CS has to find a path around the tyre to the BB shell without hitting the cranks or the chainrings. That is the real challenge. It doesn't really matter what BB shell you're attaching it to (whether it's 68mm or 73mm wide or whatever the diameter). Third, an ovalized CS doesn't have any more surface area to weld to-- it's the same perimeter, you just squashed it. In Damon Rinard's FEA (for what it's worth) round/oval/round CS were better for torsional stiffness than ones that were oval at the end. I don't know why the trend for oval. No real advantage but they are easier to weld on because you can fit your TIG torch down the middle. However I have made a number of TIG frames with ROR CS and 68mm shells and it can certainly be done. Fourth, everything gets *much* easier if you just use 650B or 26" if you want fat tyres :) But these days people seem to want 700c, really wide, and short CS hence the creative solutions like dropped CS as you said. So in summary I'm not sure all this justifies all the BB standards. There was always a use case for 68mm and 73mm and most BBs were compatible with either. But not sure we needed BB30, PF30 and all that for the CS length business. Cannondale invented BB30 I think because they wanted to use aluminium axles, which need to have larger diameters. PF30 was just the same thing but with sloppier tolerances. But regardless of BB standards it's an interesting discussion about that four way compromise between Q, tyre width, tyre diameter and CS length, and that is certainly one of the fiddler aspects of framebuilding. Another thing people do to effectively reduce the CS length (on steel frames) is curve the seat tube backwards. Finally CS length is conventionally measured down the middle, i.e from centre of BB to centre of rear axle. But it doesn't make much difference. I think on that aluminium frame the stays had probably just been squashed a bit rather than hydroformed, and of course people have been dimpling chainstays on steel bikes since forever. That can allow you to squeeze a little bit of a bigger tyre in.
This wasn’t a video about joining metals, and I wasn’t going to make it longer to start explaining terminology. Some of your other facts were quite wrong. For example PF30 helped solve the tolerance isssue of BB30. BB30 was only on metal frames and the bearing pressed directly into the shell. PF30 allowed the use of a bearing carrier to help. Cannondale still messed it up, but the thought was there.
@@Mapdec I thought that's what I said about PF30? It's what I meant anyway :)
All the way through this video I was thinking "if you want to keep the chain stays short just fit smaller diameter wheels!" I think it's crazy to go to such lengths to accommodate 700c wheels, and for what gain over 650Bs?
@@nickwinn7812 that is already done, and has been done for at least 40 years when cannondale had a 24"/26" mountain bike. can't recall which was front/rear. when disc brakes came along, changing wheel size became less of an issue (other than say bb height) and could also accommodate larger variety of tire sizes. nothing to do with bb width. 73mm were used back in the 80's and of course much wider bb's for non-road bikes. about the only time bb is a major factor is with e-bikes and their bb mounted motor.
@@nickwinn7812 I think it started with "29er" mountain bikes. The big wheels help you to ride over everything like a monster truck. But the actual rolling diameter of a 26" wheel with a fat tyre is about the same as a 700c with a traditional narrow tyre. And these are gravel bikes we're mostly talking about. So yes I don't think we need such big wheels.
Vintage old school lugged steel fan here, SO TO SAY I'm keeping it simple.
Thanks, learned something here, I got an insight into the design benefits provided by the flexibility of cf, and the reasons for newer bb's.
Such a cool explanation! Loved this.
Bike companies are also trying to reinvent the wheel with varying degrees of success.
that steel bike is georgeous!
Great video. I always appreciate a practical explanation/comparison of various bicycle geometries, and what it means to the rider. I look forward to more of these types of videos!
You are a bicycle scientist.
It's a fantastic video! As usual, it is full of information. thank you !
2:13 Thats the bike I ride. I struggle to get 25mm in, so I'm still rocking the 23mm. I love it though
Very informative, however lugged steel frames were brazed not welded. The later lugless steel frames are TIG welded as are aluminium types. 😊
I know, but I am sure everyone watching this got the idea without needing a 'what is brazing' segment.
Yes! information above and beyond. I am always curious why geometries are what they are it's always more than "handling" There are always compromises made that manufacturers won't tell you about.
Thanks. Or sometime they try to oversimplify things and it all just sounds the same.
Nice to hear Brucie's name mentioned. He built frames for both myself and my wife. Mine was sometime in the late 1980s - £440 for frame and *full* Shimano 105 12 speed groupset with SIS shifters! My wife still has her frame, now as a singlespeed.
Oh nice. 👍
Real shame that Bruce's shop closed
Great info... Love your channel....
A very, very informative video that addresses the compromises necessary to accommodate wider tyres. Learned a lot from your analysis, but still a little uncertain re the dropped chain side chainstay. Big distortion for minimal gain? Thanks and well done.
This was really good! It helped me enormously. I'm currently on a 2012 Ribble Stealth (essentially the same as the De Rosa of the same period) and I'll be finally upgrading in the next year, but I've been a bit lost. I love my current bike (obviously after nearly 13 years...), but I started to realise that I do solo endurance rides almost exclusively. Do I need nimble handling? I've got to say, "No, not at all". Even though a low and long geometry suits my body (short legs, long body, fairly decent flexibility), it's becoming clear that a race bike is not best suited for the riding I'm doing. This gives me a lot more understanding of what I'm trying to shoot for!
PAUL: the Swinnerton was BRAZED, not welded. You can't weld 531.
I know, but I am sure everyone watching this got the idea without needing a 'what is brazing' segment.
T47, internal bearing, seems to be a good idea as an improvement of the good old BSA since it has a wider area for the chainstays and threading instead of unreliable press fit.
By the way , thank you .The best explanation of my understanding of " The history of bottombrackets " ,witch have took years to summary.
that was a ton of info thank you
I had a old Mondia cyclocross bike that had a bizarre bottom bracket threading and axle length... M35 X 1.0 mm threads but the drive side was left handed, non drive right handed..And weird inside BB cup size.. nothing fit.. loose packed bearings and hope for the best...
Loads of info in this video, which I did enjoy even if a lot of it was well above my 'pay grade' 😄
Great explanation. I feel as if we have gone full circle at massively increased cost and complexity. And the benefit for the average Joe is ...?
Yeah. I think the era of BB experimentation is ending and now we are onto intergrated cockpit madness era.
@@Mapdec Paul Exactly so the industry has flogged the BB issue to death for well over a decade now its the turn of integrated headsets, more fashion in this than ladies designer shoes 🤣 Clearly the future is already behind us 🚴♂
@@Mapdec my daughter is into MTB XCO. Have been looking to progress her onto a full suspension MTB. I've settled for a Trek Super caliber SLR 9.8 XT. It has an integrated bar/stem but the hoses enter the frame behind the head tube and not through the headset. That was one of my reasons for choosing it.This will make it easier for maintenance but, also importantly, servicing will be cheaper. This push for change by manufacturers doesn't always lead to better outcomes for customers.
I had a brucies bike shop frame that I upgraded to STI’s and 11 speed. Brilliant frame and I only sold it due to toe overlap with the front wheel
Most British custom fames weren't ever welded! BMX and then mountain bikes brought TIG welding to the high-end bike industry, and it didn't get to road bikes until at least the mid-1990s, and even then British and Italian builders didn't take to it. In fact, even the best custom British MTB frames (Overbury's, Roberts, Yates, etc.) were never welded. Pegoretti and Raleigh (yes, Raleigh made pro-quality frames back then!) were some of the first road brands to use TIG welding, but they were outliers. Brazing, which is very different to welding, is how the vast majority of steel road frames were constructed until mass-produced imported aluminium frames took over from local custom steel. And, that old Trek OCLV would have seen 23mm tyres maximum. Anything wider for a serious road bike is very recent. I left the industry in 2016, and 25mm or wider tyres on a road-race bike was still a very strange idea back then. In fact, the carbon frame brand that I worked for made TT and Tri frames that would only take a 23mm tyre. A 25 (or fatter 23s from Michelin and Vittoria) would foul the seat tube cut out! 23mm Conti clinchers - or 22mm tubs - was where it was at for serious road and TT bikes. There has been a rapid demise of the high-end bicycle. What was once an elegant and beatifully simple device got caught up in a tech arms race and marketing BS. Unless it's a serious race bike, for actually racing on, all this tech and multiple standards for BB, hubs and headset is total nonsense and is killing cycling. Electronics likewise. Internal hydraulic lines likewise. odd-section seat posts likewise. One piece cockpits likewise. Tubeless likewise. We had more fun in the 1990s, 2000s and 2010s with much, much less. Club road cycling was affordable and accessible. MTB was a blast and didn't involve costly/complex suspension bikes or packing up and trekking off to distant trail centres. Bikes could be worked on at home, easily. Fit was a doddle to adjust for. Stuff lasted. Spares were standardised and simple to source. New bikes are ugly, heavy, unreliable, plastic, foreign (in every sense!), complex, fragile, tricky to work on, and very, very, very, very, very expensive. Tomorrow's landfill. Something has gone seriously wrong.
I think you are only remembering the good bits of the past. No one is storing you riding vintage gear. It’s still out there. 🤷♂️
@@Mapdec There were no bad bits in my past. Having worked for years for a top-end carbon frame brand, I now ride only steel fixed on the road and steel, rigid, singlespeed MTB. You're right, nobody stops me!!! Steel is the real deal, Neil.
There are plenty of "bad bits" in contemporary bikes, too. Bikes of all qualities have always coexisted@Mapdec
You just summed up what I've been feeling about "modern" bikes for the last decade. I think one of the problems is that many people think that if a thing is more high tech, it is automatically better, and even worse, will somehow give them a performance boost.
@@nickwinn7812 A big part of my job in the industry was to make supposedly clever people buy stuff - that they didn't need, wasn't suited to the use they would put it too, and cost more than they could really afford. It wasn't difficult, and "victims of marketing" is how we described them amongst ourselves in the office. Bexit, Trump 2.0, and the purchase of top end road bikes by cyclists who will never race race are all examples of consumers/voters (same thing) willingly acting directly against their own interests. It would seem that consumers are irrational and compulsive, and will fall for the marketing hype every time. Kerr, ching!!!
I like this video and found it useful.
didn't think a few mm would make a significant impact on handling.
A few mm doesn’t. A CM or so would.
@@Mapdec 👍
super informative
Great content.
I stay with steelframe bikes😄
The Swinnerton wins hands down!
BB length and Q-factor should vary with frame size and crank length.
No. You can adjust stance width with pedals and cleats.
I don't feel great about running SRAM Dub in a PF86. (Giant Revolt). I've never had an issue to date, and I went with a Rotor dual row ball bearing upgrade - but still.
In the BMX industry, standardisation has ruled supreme. There was a brief period (2002-2004) when screw-in 'Euro' BBs arrived. And a few manufacturers experimented with smaller diameter shells to save weight. But these innovations never took root and an industry standard emerged. Why? I think it is because the consumer demands standardisation for the sake of customisation. Riders have different needs, and they want to be able to piece together parts from different companies to meet them. In road and MTB, consumers are used to buying a complete bike and changing very little other than perhaps tyres and the bar tape.
Doesn’t BMX have 19,24 and 30mm spindles, bsa, American threads, and a couple of press fit standards too?
@@Mapdec There are two crank axle sizes: 19mm and 22mm. But the outer diameter of the press fit bearings are always the same, and there are no threaded options anymore. The parts companies' bottom brackets are identical aside from the logos on the spacers.
@ I forgot about 22mm. DXR cranks are 24mm. Isn’t there a Spanish standard as well?
Do short chainstays really help the handling that much? It makes such a tiny percentage of the total wheelbase, and I've been on some good-handling tandems, which have much longer effective chainstays. Thanks!
Depends on what handling characteristics you are aiming for. It’s quite a large proportion of wheelbase, but where weight is balanced within that, yes, has many more variables.
Great video, really opened my eyes to some of the "why"s, thank you Mapdec! Question - how much impact does frame size have on chainstay length? Is it enough to be able to fit wider tyres in larger frame sizes?
Or alternatively - is the shorter chainstay on a smaller frame size enough to make it worth using a smaller frame if you're after a bike which feels more agile?
None. Usually the rear of the bike remains pretty consistent across sizes.
Isn't at least part of the reason for increased BB diameter, the requirement for a large surface area to bond the aluminium parts to the composite parts?
I think the real reason of having so much BB's is the stupidity of manufacturers and the lack of awareness of consumers. The bike industry has forgotten what unification is and that a bicycle was originally invented as something reliable, and not to be replaced with the frequency of buying a new iPhone.
See? We made carbon wheels! But now your rim brakes don't work well in the rain? (everyone rides in the rain at top speed, huh?). Buy disc brakes, but you'll have to buy a new frame, oops. And then again: are you riding QR? Because of the disc brake, your axle can slip out of the dropout!, thru axles are safe, but you'll have to buy a new frame, oops.
But this is not enough, so each manufacturer decided to invent their own bottom bracket. And other "innovations" that you wont find it a model couple years newer.
So they produce garbage that in 20 years you will find in the garage and will not be able to get parts for it, because the experiment with the bottom bracket and unique headset/seatpost shape/fork was unsuccessful and no one makes parts for it anymore. (You already can see some frames without fork or seatpost for cheap just because its hard to find part)
But all of those brands will claim that they're green and support recycling, of course.
You are totally correct. The intergrated headset and misshaped stearer tube is the filler of much landfill
My memories that Cannondale started it all with bb30
I don't think in the time of the Trek oclv anyone was riding 25 or even 28 mm wide tyres as they were not readily available as race tyres. Anything over 23 mm would have been hard to find. Trek were probably looking for a longer wheelbase without slackening the head angle too much.
Is there any production (as opposed to custom) bike that has a chainstay of 410 mm or so that will accomodate a 700C X28mm and a large volume 650B tire? I like the idea of having an agile road bike, and am willing to go down a tire size to be able to use the same bike with a large volume tire, for gravel riding.
That doesnt sound too hard, so I suspect there are plently,
Why is there so much effort to keep the chain stays short?
I feel like this is the last hold out of the “feels fast” era. 110 psi feels fast but isn’t. Short chain stays feel fast. Are they? Is there any measurable performance benefit?
Subject of a different video. In fact probably many videos. The effect is generally no different to a car. The main difference being the cone of movement of the rider.
Short answer, short seatstays are NOT fast.
Lighter steering, think of a car with power steering vs without.
@@Mapdec hmmm. I’m not sure I understand how that translates to a performance benefit.
I think I would prefer a slightly longer chain stay in exchange for a more reliable (or consistent) bottom bracket standard.
@@and2244rew nothing wrong with BB386 or T47. Anyway. Depends how you measure performance. Straight line speed a long chainstay and long wheelbase would be better for stability. For fast corners, manoeuvring through a peloton, a shorter wheelbase would be easier to maintain speed. Most people don’t race, but like the fun of a race bike. Same with cars and motorbikes. Sports cars rarely see a track and only cruise up and down motorways. It’s crazy, but we all enjoy it 🤷♂️
That’s very interesting! I never thought about that, I just assumed it was because of the carbon
Any comments of Mapdec to new Colnago using 68mm BSA bb?)
Really odd decision. I suspect driven by the current kick back we are seeing against pressfit. The big media channels usually champion BSA. IMO it should have stayed T47i. I can see Colnago are only really interested in campy or Shimano cranks so they don’t need the bigger bearings, but even BB86 would have been a more obvious choice. Seems odd to make a very aero bike and not smooth the air flow round the BB and just plonk two outboard bearings there. BB86 would also have given more scope on the chainstay design. I haven’t seen any reviewer question it.
my new gravel bike has a dropped chainstay on it. cool times. nice ride. though it is much cheaper than the bikes displayed here.
Didn't 11 speed drivetrain specify a 425 mm chainstay length for acceptable shifting? Think I remember reading this a few years ago. The range of angles for 11 and 12 speed can be quite large on a 400 mm chainstay and lead to poor shifting.
Depends. 405mm is general minimum (bit of rounding in this vid) 1x and large chainrings can be shorter. 395 I think. Dub wide is defo 415. Fallen foul of that one.
Sorry for being instructive, but that steel frame is brazed.
😉
You don't come across as a reliable authority when you make such basic gaffes@@Mapdec
@@peterwillson1355 no one trying to claim to being a welding expert here 😂
Meanwhile on my fat bike: my 1km wide q-factor
I love long chain stays on my bike. But I also dont ride road bikes :)
One day someone will decide cranks don't need axles, we'll be in a world of hurt(s) 😅
Doesn't Shimano specify that chainstays should be at least 410 mm for disc brake road bikes? Would 400 mm stays prove to be an issue?
Depends on ratio, but generally 405
No cotter pin cranks 😮
A nightmare to be sure! I know this.
……………time to get the file out 😃
Because we're worth it
1:19 PLEASE tell me where I can get a metric only tape measure? Here in the “stupid” US of A, you can not get one
Amazon
The closed captioning seemed to be out of sync?
AI. We don’t write it all out. RUclips does the captions.
No bikes are a 400mm chainstay. The minimum is length allowed by Shimano is 405mm. The desired advantage for short chainstays is placebo at best, most people wouldn’t feel the difference between 405 and 420 but the longer will have a much better shifting and chainline due to arc tan etc etc. Also t47 internal, 386 evo have no extra width benefits over pf86. Pf86 gives you clearance for 34/35mm measured tyres with ample chainstay thickness for stiffness…
Now that is for another video… I did a bit of rounding for the sake of a short snappy vid.
@ thats some serious rounding even a builder would be proud of 😝
I just measured and mine is definitely 400mm
My Pelizzoli pista frame has 390mm stays (yeees, pista is a bit different), but still a bicycle.
For both authors of the comment and channel I wish you more time to spend with different steel bikes.
You're too young to know about short chainstays.
BBs are like they are because the bike industry hates mechanics :-)
funny how gravel bikes are basically XC bikes now.
When it has a 73 or 92mm bb it’s a MTB
Why do you need a road bike to be more agile, more nimble? It's a road bike not a freestyle BMX :D
Great question. I feel it’s one for another vid.
youtube.com/@PeakTorque - maybe you could show the tradeoffs in CAD. Especially with the shapes that can be made in carbon, I'm not getting why we can't have a bit bigger diameter BBs to help bearings actually last and have thread shoulders with more make-up face area.
Would have been nice to have seen at least one bottom bracket out of the bike.
I don’t know why you’re so stuck on chainstays. I don’t think anyone could reliably tell the difference between 400mm vs 410mm. Also even if a 400mm chainstay was by some measure ideal for a size 54, that doesn’t mean that will produce the best handling characteristics on a size 58. Years ago I bought this weird 60s Japanese frame and built it up with modest parts. I quickly fell in love with its handling and opted to ride it more than any of my other bikes, despite it being heavy and having ancient technology. That bike had 460mm chainstays on a road bike designed for thin 25mm tires! That’s longer than basically any gravel bike on the market and is firmly in hardtail territory at least! This weird geometry made steep climbing feel incredible stable, and descents feel so confident. The steering was still as quick and responsive with a high trail fork. It was the quirkiest frame that was probably only designed that way because the Japanese manufacturer was out-of-touch with what popular European Manufacturers were producing at the time. It even has the strangest 70mm wide BSA threaded bottom bracket shell!
Stuck. I made one 10min video out of collection of 600 odd, and this one mostly focused on BB development and why tyre width and Chain stay length played factor in the development of all the standards we have today. I’m glad you found it entertaining
Here's me riding a Surly Straggler with 40mm Maxxis Refuse tyres, and a Shimano, UN73 square taper bottom bracket.
Yes. Great example. Very long chain stays and ovalized at the BB weld.
Strange that none of the creators of the various bottom bracket standards said anything about chainstay length when unleashing their creations and instead touted things like weight and stiffness. it's almost like frame geometry has nothing to do with the bottom bracket standard
No. They just mention handling. Cannondale made a big deal out of it with Ai and Pf30a
@@Mapdec I'm becoming less convinced you know what a bottom bracket is or does, not even sure you know what cannondale Ai is either if you think that supports what you said
@@GaryM-ft7pw don’t worry. You’ll soon catch up. 👍
@@Mapdec I think you're probably underqualified to work assembling bikes in halfords, seriously the simple existence of bottom bracket adapters shows just how dishonest a video this is
Those Trek OCLV weren’t sluggish because the chain stays were long, they just sucked
No one ever welded 531 tubing....Im surprised this ignorance got through any editing.
Boring!
Only a few people know what brazing is. Everyone understands welding. That can be another video one day.
I'm smart, I'm smart. It's not rocket science. 🤣
Welded!?
Love this content, you explained reasons for all the changes when I thought it was change for change sake just to get people to spend more.
There is always a bit of that, in every industry, progress..
0:23 brazed, not welded…🙄 edit: I’m only 3:09 in and just can’t deal with the utter bullshit he’s talking already.
Chill. This isn’t a video talking about welding. It would get boring real fast if I had to keep going off on tangents.
According to Cognitive Market Research, The Global Gravel Road Bike market is projected to reach a size of 519.2 million in 2023, with a compound annual growth rate (CAGR) of 13.5% anticipated from 2023 to 2030.
Meanwhile is seems MTB is shrinking twice as fast.
Upper end MTB are indecently expensive which is a killer for sales.
Trend has been to gravity events so the bikes are more expensive.
Good XC trails giving way to more enduro trails - can be more fun but too hard for average beginner punter.
Imagine if, perhaps because of race coverage of Pog, road events all became long hard climbs. What would that do to the "fun" element for the average road rider?
Taking 0.5cm (or less!) off a seat stay length is surely not going to be a gamechanger for agility on a bike?! There is definitely a degree of cost saving for manufacturers (in just needing a hole for press fit rather than a threaded shell) and also wanting to create new proprietary BBs people also had to buy/replace rather than standard BSA ones anyone can manufacture...
I’m not sure I get your point. A hole is cheaper and easier than bonding an alu tube with treads into the frame.
Bottom Brackets+geometry=brain melt
I hope the rest of the video was interesting, but "welded" instead of brazed and "millimetres" instead of centimetres is so annoying that I stopped watching.
Ah. You missed out. It’s not a video to explain how metal is joined. Everyone knows that welding joins metal. Brazing is term that didn’t need explaining for this short video.
@@Mapdec Sure and yesterday did you "hammer" some screws into your wall? The other day did I "hammer" in the bolt that holds on my classic tapered crank arm onto my BSA crankset? Personally I'd use the correct verb.
Nice and insightfull video! There is only one thing that gives me a headache: Please stick to static shots! And please don't do shorter cuts than 3 seconds. I almost stopped watching in the middle of the video, because all the movement and some VERY short cuts made it hard to concentrate on the content.
Come and edit for me.
Don't try to be flashy. Unnecessary. @@Mapdec
@@Mapdec that was meant to be constructive feedback.
@@andreasruther8750 it was a genuine ask. I’m on a faster learning curve than I can handle.
@@Mapdec Finding someone in your area (or even remote) to edit your videos shouldn’t be too expensive. If that’s not feasible, there are some basic rules that you can learn quickly, some of them I tried to outline above. Some will even save you time, like your camera person only hitting the record button once the camera angle is right and only move the camera away after they stopped recording will be a huge time saver when editing (a tripod could help).
So you can decide if you throw money or time in. Or you find a film school intern, but that often ends up in more time spent in educating them, even with professionals you need to communicate and things can go wrong. So as always there is no silver bullet.
All frames about 41cm lol
Pretty much. But now with wider tyres. You got it. 👍
Dude completely glosses over the role of the CURVED SEAT TUBE. If you're willing to curve the seat tube like in the final bike, you could probably go back to a BSA BB 🙄
But then you would have tiny bearings for DUB cranks. 🤷♂️
@@Mapdec Well if manufacturers had committed to curving the seat tube when wider tires started being a thing, maybe DUB cranks wouldn't need to exist and we'd all just have cranks with a 24mm spindle.
This explains why we had ever changing bottom brackets over time. But there's still a question mark against why there's so many right now,on current bikes.
Consumer demand. We now face the problem were people are demanding BSA. We also have Shimano driving the Bb86 for OEM. Really there should be 3 standards. BB386evo for race carbon, T47i for MTB and Non race carbon, and T47 for metal frames.
@@Mapdec Paul and we all know why that is ……….an attempt by carbon frame manufacturers to side step issues created by an inability / commercial unwillingness to make two round holes opposite each other. Shame as executed well …….no issues………..but that’s the story of the ‘modern’ bike industry isn’t it ? 🤷
BS
😂
No, no. There was a huge mistake at the beginning-not all steel racing frames could fit 23mm tires only. Please, stop making it look as "typical example" of vintage bike. I worked in a bicycle shop that sells only vintage bicycles, and "23 only" is more the exception than the rule.
I personally have two top-line bikes: a 1978 time trial custom-made Woodrup, with a max tire size of 30mm, and a 1990s F. Moser road bike, with clearance about 30-32mm (measured now chainstay - 40.2cm with 28mm tires installed).
Yes, there are some bikes with (for example of the reason) unicrown lugless fork that can fit 23 max, some with Colombus Gilca tubing and fancy Chinelli BB lug - also 23max, but this is only 2 cases that my friends currently have. It mostly about late 80-90-s when bicycles became very short and tight (50-60-70-s were longer wheelbase because of not very smooth roads as one of the reasons).
Also length of the chainstays depends on BB drop and ST angle. (With higher BB and steeper ST angle you can make stays shorter)
Who said ‘all’? It’s just an example of what it is before you need to start shaping metal and lengthening stays.
@@Mapdec For me, as a person who appears alone at rides on a steel bike among carbon, this myth is a rather sensitive "point".
But in any case, I think that your conclusion in the end about the problems caused by the narrowness of the BSA and ITA bottom brackets is not very correct. Firstly, because there are a huge number of top of the line bikes with such bottom brackets and at the same time quite good clearance for tires (up to 32 mm for vintage ones) and short chainstays (shorter than 41cm). Literally two examples are in my room. Secondly, lugs are not always necessary - if you use welding or fillet brazing - you can achieve even greater capacity by the width of the tire. Also, as a "cheat" you can use a "yoke" connected to the BB (something like a plate, to make it narrow or even to go down a bit) and only after it there is a tube.
It's a bit nit picky, but I had the same thought. My '74 Raleigh International can handle 32mm tires, even though it was sold with tubulars. As noted, the 80's were all about tight clearances, so my mid-80's Hetchins has short reach brakes with the pads at the top of the slot. I've got 25mm tires on it now, but they are almost touching the brakes. One detail in the video that struck me as wrong was the suggestion that the USPS Trek OCLV frame was intended to take 25mm tires. Racers were still using tubulars then, and folks were still pumping their 23mm tires up until rock hard. Unless someone has a catalog saying that they were sold with 25mm tires, I'd contend that the goal was 23mm. I'd say that the time when BB standards were fairly standardized was when Campagnolo NR and SR were the top of the line. Tech was a bit stagnant then, and no one was changing stuff just to change it. That came later, when the manufacturers were trying to show that they had the lightest and stiffest design. Mountain bikes probably had something to do with it too? The larger tube sizes for the new frame materials certainly were a factor.
Clearly there are exceptions but think it’s fair to acknowledge that the vast majority of road bikes from that era had chainstay clearance for 23mm, 25mm max.
@@kevinfrost1579 Steel bikes? My two bikes with the tightest clearances at the fork crown and brake bridge (barely able to pass a 25mm tire) have 32mm between the chainstays. These are a '82 Raleigh Team and the mid-80's Hetchins. These are Reynolds tubed bikes, so fairly conventional. My International, which has huge clearances at the brakes, also has 32mm between the chainstays. That was pretty typical.
Because bikes are designed by engineers who have never ridden, sold, assembled or repaired a bike. Every Giant gravel bike I have ever seen had water in the internal cables which needed to be replaced $90. Horrible idea.
You sir have been awarded a PhD on the subject of chainstay length v BB shell width.
😂
unfortunately, he made too many mistakes in parts about BSA/ITA bb's and steel frames. And not mentioning BB drop/ST andgle in talk about stays length (especially comparing them by 5-10mm difference) is wrong
Let mapdec have a round 2
@@isaacrosenberg3795 it would be a very long and boring video. Short bite sized education here. Keep watching. 👍
*OCLV