smashndash

Those are practically dead and gone, now that DUB and HT2 are the dominant spindles. Small crank mfgs can’t afford to make a crank that only fits on a handful of bikes. Even Cannondale has moved away from BB/PF30 to BB/PF30A. Many T47 implementations use outboard bearings. Specialized is still holding out with “OSBB” aka BB30 but besides their S-works crank, all their other cranks are DUB, HT2 or M30 which all use outboard bearings.

I agree that Q-factors and heel clearances are important but the stiffness gains are too tempting for manufacturers.

CarloM

Yes, if either the BBright or the BB90 were truly horrible in terms of fail rate, the internet would be on fire with complaints. Especially Trek being the largest US seller. It does say something though that they're going T47. And Hambini owns a Cervelo which if you watch his previous videos, he rode a lot, with very few complaints...and I watched his long-term review of it and he didn't mention anything about the bottom bracket IIRC. It was this *other* Cervelo frame that a customer of his sent him, which had exhibited problems with his Hambini bottom bracket, which then led him down the rabbit hole to find the design drawings with the "unacceptable tolerance levels" signed off by, apparently, his arch-nemesis Damon Rinard (now at Cannondale).

Incycle is an official Cervelo dealer, and they seem to have some previous year stock they're clearancing, so I don't believe this was a one-off crappy bike (they seem to have another couple of 51cm in other local area stores, and a 61cm of it as well). I've seen this type of clearance happen for multiple brands in multiple stores (including online stores)--seems to be if you're willing to wait a model year or two later, you can score some great deals on bikes. You just have to pray that they have your size. I had been disappointed so often when I'd seen a bike I was interested in being clearanced, only to find it was in a size that was way different than mine (I can ride anywhere from a 50-52cm but most clearance bikes seem to be either very small like 48cm or very large like 58-61).

So far so good with the Cervelo. I'm crossing my fingers that I don't develop any BB problems. Though having just gotten back into cycling after a very long hiatus, I'm not even sure how long BBs are expected to last.

colnago62

According to the person I talked to at Wheels Manufacturing, weight and environment have a lot to do with how long press fit bearings will last. If you are larger and ride in wet weather, the life of your bearings will be shortened.

smashndash

Genuinely curious - why would these factors affect pressfit more than threaded BBs? Even threaded BBs use bearings that are pressed into alloy cups, which have threads in them.

redlude97

It doesn't. Just go to any cyclocross race and ask people, whether running pressfit or threaded you have to do regular maintenance on BB and hub bearings whether threaded pressfit or straight pressfit or cup and cone. Generally in those cases the bearings fail not from the loctite retaining compound failing on the outside of the bearing but rather water getting past the seals. I actually prefer my BB30 cyclocross bike because bearings cost $2-3 each and I need to swap 3-4x per race season. They don't creak when I press them out, they just get a bit gritty, and I can do a swap in ~30 mins.

HarborBandS

I don't really see that BB90 is any worse than any other press-fit bottom bracket standard. But it will be interesting to see what other major bike manufacturers adopt T47, if any. I would bet money that we see T47 on nearly every new Trek introduced in coming years. Will anyone else follow?

redlude97

BB90 is arguably the worse of the pressfits because the bearings are pressed directly into a carbon shell. At least with BB30 there is generally an aluminum shell that is machined, and with PF30 and BB92 use a plastic retainer for the bearings which are pressed in. The bearings are more likely to gall the carbon shell so commonly go out of spec faster over time for BB90

SundayNiagara

Following.

colnago62

According to the person I spoke with, the problem is bearing size and load. Press fit like BB90 and others, use smaller bearings than some of the older designs of bottom brackets. He said larger bearings resist water and contamination better.

smashndash

There's also the fact (though hard to verify for myself...) that BB90 uses a slip-fit (or "transition") vs a true press-fit (or "interference"). In my uneducated opinion, this probably has something to do with the fact that hoop stress (the "normal force" that keeps a bearing from popping out) is a function of hoop stiffness and interference levels between the shell and bearing. Of course, the bearing is similarly stiff no matter what your BB standard is. But, because carbon is not as stiff as metal (ironically), the amount of interference required to achieve a press fit would be so big that there would be a risk of cracking the frame, especially with poor tolerances. Many people have observed that they can pop out bearings by hand. So not only is the carbon shell more likely to take damage as a material, the specified tolerances don't hold the bearings in very well either.

The last part of your statement is true. And I think you're also right about, for example, square taper BBs using bigger bearings. But threaded Shimano BBs use the same bearings as press -fit ones, don't they? Many HT2 bearings are 37x24x7 - which is not an industry standard. Others use a 37x25x7 (6805) - effectively the same thing if you use a 1mm reducer. Again, there isn't *that* much of a difference between threaded and press-fit bottom brackets. The main difference is how precisely the frame needs to be manufactured and ease of assembly for the end user. If BSA bottom brackets had the same crappy tolerances as creaky frames, then even threaded BBs would creak.

redlude97

nailed it. The thing with bsa is the thread cutting tool insures the tolerances are tight and straight. HT2 are just bearings press fit into cups as well with a loctite like compound. Are the bearings actually a non standard size? They aren't 24mm ID I believe they are also 25mm with a plastic reducing shim. I'm still waiting for shimano to go to a wider aluminum axle to shave weight like pretty much every other manufacturer.

smashndash

Stock BB90 doesn’t use those reducers . Look up the Enduro BB90 kit. I have literally 0 clue as to why anyone would choose a non-standard bearing rather than a standard (cheaper) bearing and a 5 cent reducer... but such is life.

colnago62

Just got my Domane back after having a BBInfinite BB90 kit installed. It spins way better than with the Trek bearings. My plan is, since it seems to be the non-drive side bearings that fail first, at the end every month, have them opened up and have more grease shot in there.

cpach

I worked for a Trek dealer for a while. BB90 isn't my favorite thing, but it wouldn't keep me off of a higher end Trek either. My experience is in cases where the oversized bearings were too loose a fit, Trek would consider the issue a warranty, and in most cases would actually lay up new carbon in the BB and remachine the bearing seat. You are out labor to disassemble, ship, and reassemble your bike in most of these cases. An upside is that the bearings can be relatively inexpensive to replace. I saw this a couple of times, but a pretty small proportion considering the number of BB90 bikes I saw. I do think it develops problems more often than BB86.5, and it makes it so you can definitely never run a Sram DUB crank or anything with a 30mm spindle.

The bearings in BB90 are literally the same as BB86.5 bearings without the plastic retainer. They are reasonably/sanely sized, unlike, say, the bottom brackets that convert BB86.5 to a 30mm spindle.

I do think Trek will go all T47 in the future because of Sram's phasing out of GXP in favor of DUB and the current premium eTap AXS has, but a fair amount of their 2020 models. I wouldn't be surprised if they held off on Emonda in particular given their love of extremely low frame weights for marketing that line, and T47 still probably adds a small amount of weight.

drewguy

Not much of a warranty if you have to cover all those costs!

smashndash

I’ll start off by saying I don’t trust any company to follow through on warranty claims anymore after the horrible experience I had with Specialized. I’d rather just get a bike that works out the door. I know Trek is not Specialized but specialized also has a good reputation when it comes to warranties.

You touched upon the reason why I absolutely hate BB86. It seems like it was *specifically* designed to keep out 30mm competitors and lock BB86 frames to shimano groups. Now, some people still bodged their way in and SRAM bodged even harder and developed DUB. Shimano basically forced SRAM to bend the knee.

Quite a few Trek models use BB86 or BB92 now. I assume that this means the weight weenie frames will use that going forward, and all the budget-friendly frames will use T47. For some reason, Trek still lists their top end Domane as using GXP spindles even though T47 should fit DUB. It’s ambiguous with the Domane SLR Force - they just say it uses a Praxis BB. I wish bike manufacturers didn’t get away with not listing various specifications.

cpach

That's a valid point of view, but really a couple hundred bucks in labor is a lot less than over a thousand for a frame. It is significantly better than not covering the frame repair, considering a lot of brands would consider wear to a bearing bore wear and tear. It's also a good time to overhaul the bike since everything's coming off, anyways. A lot of shops will discount the labor somewhat if you got that bike from them, but just straight can't do it for free if they're not getting a labor credit from the manufacturer. The only brand that has consistently given labor credits in my experience is Sram, for what it's worth , usually in the form of lots of replacement parts.

To be honest I would not say that Specialized has a good reputation with warranties. Honestly, as a mechanic working at a Trek retailer, I never saw Trek deny anything even remotely legitimate. Organizations are made of people, and people vary, so I'm sure they've failed people before, but that's been my experience.

drewguy

Yeah, I take the point, but it's a more general issue with warranties that say they cover X, but then to get X covered you have to do a lot of spending on your own. I don't begrudge a shop charging for what Trek won't pay them to do, but Trek should pay it.

Analogy - if your car has a warranty on the engine, but to fix it they have to remove a bunch of other stuff and charge the labor for that, it's not much of a warranty. So maybe Trek should call it a "limited" or "qualified" frame warranty.

CarloM

I just wanted to acknowledge @smashndash and how he got "bend the knee" into his post discussing Shimano and SRAM. Well played.

john.b

After six summers I finally had the BB90 bearings replaced on my MY 2015 Domane 5.2 (purchased July, 2014) after noticing some creaking while standing during steep climbs — which didn’t go away with different pedals/shoes. The old bearings definitely had to be coaxed out and the new ones pressed in, nothing “loose” about either of them. The bike is as quiet now as it was when it was new.

One thing that was interesting was that the dust caps on the new bearings were a different style that came attached, for lack of a better word, where the original dust caps were easily removable.

Hasn’t BB86 been compatible with SRAM GXP since... well... forever?

SRAM has been putting their AXP groupsets with GXP BBs into the Emonda/Madone/Domane BB90 frames but, AFAIK, the GXP versions are only available to Trek and only on an OEM basis. I’ve not seen them available as aftermarket cranksets.

It must have something to do with the way Trek as of late has been smitten with SRAM, much to my chagrin.

shawneo38

Dont buy any bike with this bottom bracket. Took my bike in two weeks ago because of the creaking issue and got it back recently. Trek replaced the bearings with a "one time replacement". Went on 1 ride. Decided to search this issue because the repair doesn't sit well with me. I decided to take the chain off and give the crank a spin only to be disappointed with the stiffness of the bearings. The crank comes to a complete stop fairly swiftly. I'm taking it back asap to see what will happen but I am not expecting it to go well. I have a 2018 Emonda SL7 Di2. Retail here in Canada is over 6k. The Bike is just over two years old, has never seen a winter and Ive only been caught in the rain once. Starting at about the end of year 1 I started hearing creaking. The bike has been in several times for this issue. Never once did the bike shop suggest overhauling the BB but I did have the bike thoroughly cleaned at the shop on several occasions. Trek blamed the failure on me not doing proper maintenance. The bicycle has about 12000 km on it. Im really not happy with Trek and when I look at my bike I see a piece of junk when I used to see a thing of beauty. I also have a Trek Farley 9.6 Fat Bike and it's creaking too!!!

SundayNiagara

So, are there any plans to incorporate the T-47 into older models? I have a first gen Emonda.

RiceAWay

BB90 and BB95 are press-in bearings. That means that inevitably they have problems. Because you can get a frame at the large end of tolerances and a bearing on the small end of the tolerances, you can get a slightly loose fit. This can cause it to move under load and make noise. It does more than just make noise - it wears the carbon fiber surfaces. This is why you should immediately take a noisy push-in bearing of any sort in immediately. A mechanic can measure it and see if it is an under tolerance bearing, (can you say Chinese?) still within tolerances or not. This is a bad enough problem with BB90 that Trek has a repair kit that has a bearing 0.1mm larger than standard and some sort of glue so that you can clean everything up, place the glue inside the frame receptacle and push in the slightly larger than standard bearing (37.1 x 24 x 7 mm). This usually stops it unless it has gone too far. If that is the case (the mechanic is supposed to carefully measure the receptacle) they have yet another type of glue that has a filler in it. I haven't seen the manual but suppose that you put this stuff in, push in the bearings and then put the crankset in to keep it aligned while it dries.

I agree that we ought to standardize BB's to T47.

RiceAWay

The BB90 is just narrow enough to fit a standard Shimano crankset in it with a 24 mm axle. The bearings themselves are 7 mm wide each so that would make it 14 mm wider that the cranksets. The measurements of the bearings are 37 mm OD and 24 mm ID so as you can see there'd be no room to make some sort of internal bearing assembly and still leave room for an inner and outer race that was stiff enough and balls that could run in them without crushing.

So, no, the older BB90's are stuck with it. They are usually faultless though. It is only the very seldom cases of tolerances off in the opposite directions that a problem occurs and any Trek shop either has or can order the repair kit to fix it.