Hiro11

This is a good point. A poorly aligned threaded BB (like the one on my gravel bike) makes a ton of noise and the misalignment will kill bottom brackets quickly. I've had to replace the BB pretty much every year in that bike. Meanwhile, the BB86 in my Giant is going on 10K miles will nary a sound and still spins glass smooth despite riding it in all conditions. I'm also reminded of all of the issues I had with both sealed and non-sealed square taper 25 years ago, my bikes in the early nineties were essentially never quiet. The mere presence of threads is no guarantee of a problem-free BB. On the other hand, I installed an Ultegra external threaded BB in one of my roads bikes ten years ago and I haven't had to think about it since.

IMO, the undeniable strength of a threaded BB is that someone with no skill like me can replace them quickly with a $15 tool to (temporarily at least) solve any problem.

63rickert

No, not at all. It means most bikes are never ridden much. It means most bikes that are ridden are never ridden hard. And most bike owners will tolerate most anything. Those I know who have to replace BB bearings very frequently never blame the bike. It is just how it is and they accept that bikes costing five and ten thousand dollars simply need constant maintenance. The only complaints are when multiple expensive attempts to resolve the creak don’t succeed. Until the problem is very very bad no one admits that the expensive bike is very cheaply made.

Wildwood 

Who thinks manufacturers would be returning to threaded BB if it was not a better solution?

tomato coupe

So, people are either unaware of how bad their BB is, or they are too embarrassed to admit how bad their BB is? Pure nonsense.

Dan Burkhart 

Yes, they will tolerate much, but not irritating noises and that's what the press fit bottom bracket debate seems to boil down to for the most part.

Leinster

This. But also.

Threaded BBs are easier to cost-effectively manufacture to tolerances which allow for ease of maintenance by home mechanics/inexperienced shop mechanics, to the satisfaction of said home mechanics, based on feedback from more than a decade of threadless BBs being out in the wild, versus multiple decades of the threaded BB. The combination of all those factors has led the industry to determine that the threaded BB is the optimal option.

tomato coupe

I don't think "the industry" has made that determination. Most manufacturers are still churning out bikes with press fit bottom brackets.

Hiro11

I disagree, most people who I know who have had bottom bracket issues on expensive bikes have been VERY vocal about it and certainly willing to publicly call out the manufacturer of their frame. Witness any online discussion since about 2009 on the topic. I actually think people who have had issues have been so vocal that the level of problems is likely overstated. Most people don't have issues, like Tomato Coupe said.

rosefarts

I think it goes beyond that they just need to work and spin smoothly. It's that they need to stay quiet even on an empty road and most bikes seem to amplify sound.

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Leinster

The premise of this thread from the OP is that "bike manufacturers like Specialized and Trek seem to be moving back to threaded BB."

I suppose you could preface my post with the caveat that "If this move back to threaded is true..." I've never had a problem with the BB30 on my CAAD10, but I do know people who have had issues with press-fit.

My main BB issues were with the old loose-bearing ones back in the day, and since my first cartridge BB in the early 90s I've pretty much stuck to that.

tomato coupe

I don't see that quote in any of the OP's posts. Can you point me to it?

Leinster

I paraphrased from the OP rather than quote, sorry for the confusion;

tomato coupe

Okay. So, TREK is moving to T47 and Specialized is going to use BSA on some of their bikes. That seems to fall a bit short of "the industry."

63rickert

If more than a small handful had been vocal the industry would have responded.

The bearings in the BBs being discussed are high quality bearings. They are designed and built to give thousands of hours of service. The are oversized and should be understressed on a bicycle. That they fail so quickly is due to misalignment and bad fit. There is no difficulty in producing accurate frames with accurate BB shells. All you have to do is tell the fabricator what the specs and tolerances are. And then pay for it.

The brands with BB shells wildly out of spec do not lose sales because of that. They sell very well. The handful of builders who pay attention and build accurately are tiny niche brands. (Or they are metal frames.)

No one cares. People defend their overpriced purchases. A whole generation of riders have been taught that bearings cannot be expected to last more than a thousand miles. And if it is less than that you could live with it. If you get two thousand celebrate. Even at a thousand miles the bearings I see are not worn or worn out. They have failed. They failed a good while before they were removed.

Again, SKF, NTN, *** bearings are built for thousands of hours of service. Automotive bearings routinely give 5000 hours of service and twice that or three times that is not unusual. If the main bearing in your auto crank failed after 100 hours something would be very wrong. Apply that to bikes.

Hiro11

I agree with all of that. I was just disagreeing that owners "tolerate" problematic bottom brackets. I do agree that people should probably blame manufacturers rather than press fit itself. The other thing that annoys me are high end bikes that spec crappy bearings. Wholesale on a pair of good Japanese 6806-2RS bearings is probably $10 and will be much better than anything OEMs use. Too many manufacturers sell you a $10K bike with garbage bearings. It's like expensive stems that have cheap pot steel hardware that round out and rusts instantly. They're saving $0.05 a unit by not using something high quality and stainless and screwing their customers. Sometimes I hate bike manufacturers.

tallbikeman

American bicycling was built on the one piece crank with press fit bearing cups in the frame. Frames were steel as were the bearing cups. Having serviced many of the older style (still being manufactured today) bottom brackets the steel frame to steel cup is integral to the quietness of this design. The cups are pressed into the frame or beat in with a rubber hammer so their is a total interference fit. Nice quiet bottom bracket. Such a simple successful design. The American bottom bracket standard is still bigger diameter than all the other bigger bottom bracket standards out there. It is sad that in this day and age a bottom bracket patented in the 1890's is better thought out and engineered than these noisy new comers. At my age I hear the creaking and and god awful clunking before they pass me on the bike trail on their carbon fiber super bikes. I personally can't stand little mechanical creaks and clunks coming from my bike, they drive me batty. I should say more batty than usual. Can't we just graft the steel bottom bracket off a mid 60's Schwinn Varsity onto these carbon wonders and quiet them down please.

DaveSSS 

I spent a little more for wheels manufacturing thread together bottom brackets with angular contact bearings for my most recent two bikes. They require a special splined tool to tighten the flanges, but I found that my ancient 1 tooth tool for installing square taper BBs worked with a little grinding to make better contact. I tried shimano press fit BBs first, but wasn't impressed. These spin nicely with no creaks and no loctite. I lightly greased the contact areas.

https://wheelsmfg.com/bottom-bracket...nks-black.html

Rolla

The only bikes I've had with press-fit BBs were BMX bikes -- both "American" (with cups) and "mid" (no cups). Neither was as reliable, quiet, or easy to service as a threaded unit. Both of my BMXers have "Euro" (threaded) BBs now. Threads and grease is a pretty damn well-proven technology.

John_V 

I had a Hawk Racing BB86 installed on my Colnago CRS when I purchased the bike new. Two months, and roughly 2,000 miles, after I got the bike the BB started creaking. My LBS did everything they could to keep it from doing so but couldn't get it stop. The BB on this bike fits into a brass shell and not directly into the carbon fiber so it should not have started creaking so soon. I replaced the Hawk Racing with the BB you linked to except with ceramic bearings. That was three years and 28,000 miles ago.The BB is just as tight, quiet and smooth as the day it was installed. If I ever get another new bike with press fit bearings, they will be replaced with a Wheels Mfg BB on day one.

'02 nrs

the more things change.............................................

Hiro11

Definitely not, as the Hambini video above makes clear. Press fit is theoretically superior to threaded from an alignment perspective due to radial clearance inherent in any threaded design. Of course, many manufacturers have garbage bearing alignment in the BBs so that benefit remains "theoretical".

A benefit of threaded is that even if the alignment of the two sides is poor, it won't creak. This is because of the inherent flex in the system. Of course, the poor alignment will still eat threaded BBs over time (witness my current gravel bike), but at least with threaded replacing them is pretty easy.

The irony for me here about all of this is that one of the reasons press fit came about is because threaded BBs in the 80s and 90s were often annoyingly creaky. The cartridge square taper in my 1992 Cannondale M800 and later the one I had in a 1995 Specialized Stumpjumper both creaked all the time. It used to drive me nuts. The cup and cone, Italian threaded Dura Ace BB in my 1992 Tommasini racing bike required frequent overhauling and regreasing to keep it quiet, as did the cheaper Sugino unit on my mid-80s Bianchi touring bike. Neither of those units ran particularly smoothly ever. I used to replace the loose ball bearings in the Dura Ace unit at least twice a year which was a tedious and messy job. Ritchey, Klein, Merlin and Fat Chance were all trying to solve those problems with those early press fit BBs.

DaveSSS 

I had two 2017 CRS frames. The BB presses directly into carbon fiber. At the time, I was using Campy drivetrains. Campy cranks have bearings mounted to the spindles and empty cups that press into the frame. I greased the Campy cups when pressing them in, rather than using loctite. I heard a little creaking, but creaks can also come from other places, like the rear skewer not being tightened enough on a rim brake frame. If I still had Campy cranks, I'd probably try the BB infinite solution. https://www.bbinfinite.com/products/...ant=9864643843

Now using Shimano cranks with my AXS drivetrain, the thread together BBs seem to be the perfect solution and less expensive than the BB infinite.

63rickert

I will be the first to admit that old style BBS can be hit or miss.

Hambini has one video where where he shows a threaded BB which has had the two sides of a metal BB shell tapped independently. Of course the two sides do not align. Taps for metal BB shells always have a guide and both sides are tapped at same time. The only way this can be done wrong is when subcontractors with minimum fabrication experience and no bicycle experience at all are drafted into service by importer/distributors who do not care. Sales organizations that want your money. Good enough to sell, not good enough to ride. Customers who support and praise such vendors get what they deserve and ruin bikes for everyone else.

Old school BBS as in your Tommasini or Bianchi had trivial or non existent sealing. If used hard in rain or used for commuting in winter salt slush absolutely they needed continual maintenance. If serviced inexpertly they needed continual maintenance and regular replacement. If well cared for and kept dry they can last decades and get 1000 hours between regreasing. If used regularly and hard on wet roads only the most fastidious and compulsive owners will get long service.

Sealed BB bearings have been around a long time. At least since 1950s. Good ones are and long have been problem free and maintenance free. They last the life of the bike. Problems occur when corners are cut. My first sealed BB was a Phil. The old ones that were made in the garage personally by Phil. Thing seized solid on a fixed gear bike and threw me while in heavy traffic. Yes, if you make stupid mistakes there will be problems. At start of paragraph the word ‘sealed’ was used. That means sealed. Most BBs still only use minimal dust shields.

Cup and cone bearings were used a very long time because they are self-aligning within a huge range of error. They kept being used because everyone understood bicycles have rarely been built to high tolerances. When cup and cone was largely abandoned there was no corresponding shift to precision. If the BB is made as if the bicycle is precise it just cannot work when the bike is shoddy.

In the bike business it remains very common and very simple to substitute advertising for engineering, to substitute advertising for quality. Spend the dollars on promoting junk and there is a willing army repeating every word from the copy writers as if it were fact. Discriminating consumers who won’t buy or endorse junk ar not common. Campagnolo refused to build pressfit BBS for quite a few years, because they knew they wouldn’t work, and relented only when sales hit zero. Bike parts are just a legacy line for Campy, it is an engineering firm. They knew the bikes that would work with pressfit did not exist. Holding on to standards would have ended Campy if they didn’t have lots of other business.

Leinster

So one overwhelming conclusion is that threadless would work best, if bike manufacturing tolerances were up to spec.

So that leads to the crucial question; what can bike manufacturers change in their processes to match the required tolerance levels? Is there a quick, straightforward fix that can be implemented to carbon mould assemblies, metal welding rigs, etc, that will guarantee that the BB shell is always perfectly round and aligned, and won’t flex under pedaling loads? And if so, why don’t manufacturers implement it?

Branko D

From the point of view of bike brands? Give more stringent tolerances to their manufacturers in China / Taiwan and pay somewhat higher costs for the frames. The manufacturers will solve the problem, it just costs a bit extra.
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Bike brands are the issue; when first tier bike brands who charge an arm and a leg for ther frames have no better and sometimes worse BB tolerances than the "in house" brands of Chinese bikes, something is just wrong with that picture.
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