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Now that everyone is going with threaded bottom brackets...

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Now that everyone is going with threaded bottom brackets...

Old 02-06-21, 02:48 PM
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Hiro11
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Now that everyone is going with threaded bottom brackets...

At risk of beating a dead horse...

Trek has adopted the threaded T47 standard for most of their new bikes. Specialized is moving back to the ancient BSA standard on some new bikes, although many of their bikes are still using the "OSBB" press fit standard(s). Santa Cruz and Pinarello never implemented press fit in the first place (although Pinarello uses the wacky Italian threaded standard). While most other brands are still using press fit BBs, everyone seems to be rejoicing at the return of threaded BBs. Like many here, for years I would automatically cross a bike off my list if it had any type of press fit BB.

Still... I now have over 10k miles on a Giant Defy with a BB86 with no issues. I have a 5 year old Seven with a BB30 that's silent and smooth. While I certainly know people who have had issues with press fit BBs (especially Trek BB90), I know far more people who don't even realize they have a press fit BB because they've never had to deal with it. I know people with Merlins and Kleins from the early 90s with ancient press fits that have been completely abused and are still going strong. Also, there's a reasonable argument to be made that press-fit interfaces offer superior alignment in most applications compared to threaded interfaces, which is one reason why essentially every bearing in every application in the world outside of bicycle bottom brackets is press fit.

The main issue with press fit BBs seems to be most press fit standards require tight manufacturing tolerances. Bike manufacturers likely implemented press fit because it was cheaper and allowed them to offer lighter frames. Most brands seem to not have implemented the manufacturing practices needed to maintain the necessary tolerances, likely because properly machining a press fit interface is expensive in metal and essentially impossible in carbon. Maybe some brands just do a better job, maybe some "standards" are better than others...

I've come to the conclusion that I still prefer threaded, mainly because I can replace the BB at home quickly if anything goes wrong. On the other hand, I also think press fit has gotten a slightly unfair rap. Done right, press fit can be really good and problem free. The problem is most brands didn't do it right.

Last edited by Hiro11; 02-06-21 at 03:13 PM.
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Old 02-06-21, 03:04 PM
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The problem is most brands didn't do it right.
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Old 02-06-21, 04:30 PM
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It is a testament to horrible QC and manufacturing tolerances of the bike industry, in multi thousand dollar frames no less, that press fit was a problem to begin with.

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Old 02-06-21, 04:37 PM
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Hopefully within a couple of years PF will just be a bad memory.
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Old 02-06-21, 05:16 PM
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Originally Posted by Branko D View Post
It is a testament to horrible QC and manufacturing tolerances of the bike industry, in multi thousand dollar frames no less, that press fit was a problem to begin with.

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This is my point. Every other industry including automotive, industrial equipment, appliances, HVAC etc uses press fit bearings exclusively. These applications are almost always dealing with orders of magnitude higher loads, more heat and harsher environments than bikes and press fit is still the better solution. Even within the bike industry, press fit works fine in hubs. Press fit BBs should work great (and do in many cases). The fact that press fit doesn't work always tells me more about poor frame manufacturing than about the standard itself.
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Old 02-06-21, 10:27 PM
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Originally Posted by Branko D View Post
It is a testament to horrible QC and manufacturing tolerances of the bike industry, in multi thousand dollar frames no less, that press fit was a problem to begin with.
...and so many people point out, with regularity, that Giant makes frames for nearly everyone, who just puts their name on it. So, Giant makes crappy frames? Interesting.
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Old 02-06-21, 10:37 PM
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It's all in QC or lack thereof

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Old 02-06-21, 10:55 PM
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Every frame I've ever owned has been dressed out with nice threads. I see no good reason to not spoil them in that manner.

And slightly more seriously - threaded bottom brackets work really well. They are one of the more ignored areas of my bikes. (Well, until I started playing with Q-factors for my knees. Not sure press fit would have made that journey any easier and it would have eliminated those wonderful low Q old Sugino cranksets I believe. And in that journey, swapping bottom brackets has been easy. No skill required at all. Just a big wrench and a means to secure it. Home Depot stuff. Skill required at the build? The threading tool. Yeah, what $100? $150? And it's good for how many dozens or hundreds of frames? And yes, you don't have the custodian doing the tapping but don't need the master either.)
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Old 02-06-21, 11:01 PM
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Originally Posted by AdkMtnMonster View Post
...and so many people point out, with regularity, that Giant makes frames for nearly everyone, who just puts their name on it. So, Giant makes crappy frames? Interesting.
I believe Giant will build whatever you spec and pay for. Spec a fine race-quality frame with the best CF and details (and pay for it) and Giant will build it. I suspect they are just as willing to build you a $10 piece of junk if you spec that, step up and pay the $10.
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Old 02-07-21, 12:44 AM
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BSA is an old standard but ancient is not fair. Absolutely nothing wrong it at all nor having an older age. If we were still using cottered cranks I could see the ancient but a modern external threaded B.B. is hardly ancient even if BSA threaded.

Press fit could potentially work quite well for a B.B. if manufacturers had ultra high tolerances and gave more of a crap but honestly T47 sort of solves a lot of the issues that press fit existed for (like larger bb shell and bigger bearings) and solves those issues that we dislike about press fit. It isn't perfect but probably not a bad idea if we want stiffer B.B.s and larger bearings.
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Old 02-07-21, 01:14 AM
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Working on press fit BB when the frame is reasonably made is easy; I've got two in house, a Fuji and a Canyon and neither gave me any issue. It takes a removal tool, a bearing press, Loctite 609 and a big hammer.

​​​​It’s a slight bit more work than a threaded bike, but all things being the same is lighter if nothing else. If I was buying a new bike, I'd rather grab a pressfit Canyon than a threaded Specialized or Trek for that reason alone even if price wasn't a factor.

Last edited by Branko D; 02-07-21 at 02:43 AM.
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Old 02-07-21, 03:58 AM
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PF & TF both shown me that an owner can make either option be a nightmare or easy work. As with most things, it "depends".
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Old 02-07-21, 08:58 AM
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Originally Posted by veganbikes View Post
BSA is an old standard but ancient is not fair. Absolutely nothing wrong it at all nor having an older age. If we were still using cottered cranks I could see the ancient but a modern external threaded B.B. is hardly ancient even if BSA threaded.
I didn't mean to imply that BSA is inferior. It's also not perfect, though. The last three BBs I've had to replace were all BSA-based external cup setups on my gravel bike, fatbike and hardtail. In fairness, those bikes went through a lot of gritty/wet rides which will kill most any BB and replacing them all was easy.

Press fit could potentially work quite well for a B.B. if manufacturers had ultra high tolerances and gave more of a crap but honestly T47 sort of solves a lot of the issues that press fit existed for (like larger bb shell and bigger bearings) and solves those issues that we dislike about press fit. It isn't perfect but probably not a bad idea if we want stiffer B.B.s and larger bearings.
I own a Seven and with a BB30 bottom bracket shell that works well. In order to get their required level of quality, Seven CNC machined their BB shells all the way through both sides. That will get you the accuracy necessary to implement press fit well, but it requires very expensive tooling especially in titanium. Because of this, Seven charged a whopping $295 extra for a BB30. That price gives me an idea of how hard it is to get it right. I don't think volume manufacturers can scale up that type of precision cheaply. Note that Seven went back to only offering BSA and T47 recently, which I think is telling: if you want it to be reliable, press fit is a ton of work for debatable customer benefit.

Last edited by Hiro11; 02-07-21 at 09:02 AM.
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Old 02-07-21, 09:10 AM
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Other industries using press fit are mainly using them with hardened steel, not aluminum & carbon fiber contact areas.
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Old 02-07-21, 12:04 PM
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I never understood all the fuss, problems, either way. I always assumed I was missing something.

I remember the first bike I built up with a press fit bb was a BMX frame for one of my kids. I watched a video from Jim Bauer at Odyssey showing how to press in sealed bearings and spindle etc, and he specifically said this is all much easier in installation and use if the frame has been well-built. I just assumed thatíd be the norm! You ever see the force that those guys put through their cranks? Yet nobody complains about ill-fitting or failed bottom brackets.

Road bikes (and MTBs too) have different concerns and stresses than BMX, obviously. The only road bike Iíve had with a press-fit one has also been fine. Guess Iíve been lucky, and I donít really care what standard my next bike has, as long as manufacturers start including a bb servicing tool along with each new purchase! (No really, I mean it.)
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Old 02-07-21, 01:11 PM
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Originally Posted by Hiro11 View Post
The problem is most brands didn't do it right.
The vast majority of bikes with press fit bottom brackets are trouble-free, so most brands must be doing it right most of the time.
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Old 02-07-21, 01:48 PM
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From a manufacturing standpoint, whether you're making bicycles or hubcaps, all things being equal a design that requires tighter tolerances is less desirable. When tighter tolerances deliver better function, it's a business tradeoff.

From a marketing standpoint, tighter tolerances have become associated with higher quality, even though they can result in more failures and higher maintenance cost. For the company, this can mean higher warranty cost and damage to the brand image.

Assuming press fit actually does require tighter manufacturing tolerances - I simply don't know if this is true - it would be surprising manufacturers didn't know that beforehand.

In an industry where product differentiation is important yet hard to come by, questionable innovations are inevitable.
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Old 02-07-21, 02:04 PM
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Originally Posted by Hiro11 View Post
At risk of beating a dead horse...

Trek has adopted the threaded T47 standard for most of their new bikes. Specialized is moving back to the ancient BSA standard on some new bikes, although many of their bikes are still using the "OSBB" press fit standard(s). Santa Cruz and Pinarello never implemented press fit in the first place (although Pinarello uses the wacky Italian threaded standard). While most other brands are still using press fit BBs, everyone seems to be rejoicing at the return of threaded BBs. Like many here, for years I would automatically cross a bike off my list if it had any type of press fit BB.

Still... I now have over 10k miles on a Giant Defy with a BB86 with no issues. I have a 5 year old Seven with a BB30 that's silent and smooth. While I certainly know people who have had issues with press fit BBs (especially Trek BB90), I know far more people who don't even realize they have a press fit BB because they've never had to deal with it. I know people with Merlins and Kleins from the early 90s with ancient press fits that have been completely abused and are still going strong. Also, there's a reasonable argument to be made that press-fit interfaces offer superior alignment in most applications compared to threaded interfaces, which is one reason why essentially every bearing in every application in the world outside of bicycle bottom brackets is press fit.

The main issue with press fit BBs seems to be most press fit standards require tight manufacturing tolerances. Bike manufacturers likely implemented press fit because it was cheaper and allowed them to offer lighter frames. Most brands seem to not have implemented the manufacturing practices needed to maintain the necessary tolerances, likely because properly machining a press fit interface is expensive in metal and essentially impossible in carbon. Maybe some brands just do a better job, maybe some "standards" are better than others...

I've come to the conclusion that I still prefer threaded, mainly because I can replace the BB at home quickly if anything goes wrong. On the other hand, I also think press fit has gotten a slightly unfair rap. Done right, press fit can be really good and problem free. The problem is most brands didn't do it right.
Actually, Pinarello did adopt press fit but went back to Italian threading within a year or two.
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Old 02-07-21, 03:37 PM
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I've never had a bicycle that had a press-fit bottom bracket, they've all been square-taper designs. They range from a 1977 steel Schwinn LeTour Lux to a modern-day 'non-name' cyclocross frame I purchased about 4 years ago and built up myself. The mechanism is in a sealed cartridge, easy to replace with standard tools, and inexpensive, too!.

FWIW: All the bikes I have are equipped with press-fit headsets - will those be going away too, replaced by 'integrated' headsets? I've never ridden a bicycle with an integrated version, but it looks somewhat similar to a press-fit BB arrangement.
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Old 02-07-21, 07:19 PM
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Originally Posted by Hiro11 View Post
I didn't mean to imply that BSA is inferior. It's also not perfect, though. The last three BBs I've had to replace were all BSA-based external cup setups on my gravel bike, fatbike and hardtail. In fairness, those bikes went through a lot of gritty/wet rides which will kill most any BB and replacing them all was easy.

I own a Seven and with a BB30 bottom bracket shell that works well. In order to get their required level of quality, Seven CNC machined their BB shells all the way through both sides. That will get you the accuracy necessary to implement press fit well, but it requires very expensive tooling especially in titanium. Because of this, Seven charged a whopping $295 extra for a BB30. That price gives me an idea of how hard it is to get it right. I don't think volume manufacturers can scale up that type of precision cheaply. Note that Seven went back to only offering BSA and T47 recently, which I think is telling: if you want it to be reliable, press fit is a ton of work for debatable customer benefit.
Exactly and probably no fault of threading, any bottom bracket in sloppy gritty conditions will need more frequent replacement.

Yeah you need to be exact with press fit stuff vertically it seems to do all right for headsets but after that they sort of crap out unless machined well and that is few and far between. Seven knows WTF they are doing, granted they have been at the game for a while doing some of the best work.
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Old 02-07-21, 07:30 PM
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Originally Posted by tomato coupe View Post
The vast majority of bikes with press fit bottom brackets are trouble-free, so most brands must be doing it right most of the time.
This is a fair point.
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Old 02-07-21, 08:42 PM
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the REAL problem with pressfit bb's is when you change out the bb for a new one. That is when carbon shell loosen up and now when you put in a new bb, creaks.
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Old 02-07-21, 09:47 PM
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Originally Posted by downtube42 View Post

From a marketing standpoint, tighter tolerances have become associated with higher quality, even though they can result in more failures and higher maintenance cost. For the company, this can mean higher warranty cost and damage to the brand image.
OK. I might be totally off-base here. But it sounds like you misunderstand what "tolerance" means.

https://www.thehighroad.org/index.ph...vs-fit.686715/

Tolerance is not the same thing as fit. You can have a part with extremely tight tolerances but a very loose fit. Similarly, you can have a part with very loose tolerances but a very tight fit. The latter is extremely common with press fit bottom brackets. Hence the adoption of pliable nylon bottom brackets.
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Old 02-07-21, 10:22 PM
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Does a threaded BB really solve the problem of poor manufacturing techniques and tolerances on (some) CF frames? Since the BB is built around around the shell on CF frames, rather than the shell being a strong load bearing joint as on welded frames, it still seems like there is plenty of opportunities for manufactures to use weak shells that will cause the cups to become misaligned over time. Just because the BB threads in doesn't mean it's magically stronger, and better aligned is what I'm getting at.

Not hating on threaded BB's though; I went out of my way to get a T47 BB on a steel gravel bike so I could run a 30mm spindle with the bigger bearings and flanges that T47 allows.
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Old 02-08-21, 12:20 AM
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Originally Posted by zen_ View Post
Does a threaded BB really solve the problem of poor manufacturing techniques and tolerances on (some) CF frames? Since the BB is built around around the shell on CF frames, rather than the shell being a strong load bearing joint as on welded frames, it still seems like there is plenty of opportunities for manufactures to use weak shells that will cause the cups to become misaligned over time. Just because the BB threads in doesn't mean it's magically stronger, and better aligned is what I'm getting at.

Not hating on threaded BB's though; I went out of my way to get a T47 BB on a steel gravel bike so I could run a 30mm spindle with the bigger bearings and flanges that T47 allows.
It creates a higher floor for tolerances. You're probably less likely to have bearing-crushing issues because thread-tapping tools require precise boring. You're also unlikely to have wallowing or slop. So obviously less chances of creak.

You are right that threaded BBs will mask some issues and the bike industry will try to convince us that threaded BBs can do no wrong and are all perfect - and we'll probably buy it. But it's definitely the lesser of two evils, from what I can see.

The optimal solution would probably be good threaded shells for low-end or non-racing bikes and high quality pressfit shells for high end racing bikes. But the bike industry cannot be trusted to do pressfit well at any cost level.
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