So, about the Madone and the BB90 issues: legit or overblown?
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I agree that Q-factors and heel clearances are important but the stiffness gains are too tempting for manufacturers.
#27
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The crazy thing about tolerances is that it’s usually only a minority of people affected by them. Even a broken clock is right twice a day. I would say even a 2% defect rate would be enough to cause a significant amount of noise online. But that also means, if you select a bike randomly (hopefully this bike wasn’t on clearance because it was crappy), you could have a 98% chance of nothing being wrong. It seems like more than 2% of BB90 bikes need some sort of fix - oversized bearings are one of them, but that’s a bad solution for hopefully obvious reasons.
BBright is a better standard than BB90 *theoretically* because it allows for a sleeve, even with 30mm spindles.
BBright is a better standard than BB90 *theoretically* because it allows for a sleeve, even with 30mm spindles.
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.
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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.
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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.
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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.
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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?
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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?
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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.
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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
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.
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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.
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.
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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.
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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.
#39
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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.
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.
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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.
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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.
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.
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.
Last edited by smashndash; 09-20-19 at 10:23 AM.
#42
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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.
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.
#43
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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.
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.
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.
#44
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I just wanted to acknowledge @smashndash and how he got "bend the knee" into his post discussing Shimano and SRAM. Well played.
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#45
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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.
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.
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.
It must have something to do with the way Trek as of late has been smitten with SRAM, much to my chagrin.
Last edited by john.b; 09-30-19 at 09:03 PM.
#46
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Based upon the 2020 Domane, I'd say that the T47 BB move is more than a rumor.
But, to the subject at hand - I wouldn't avoid a BB90 Madone, but all things equal, I'd take a T47 Madone over a BB90 Madone. That said, I'm price sensitive enough that I'd totally jump on discounted Madone with BB90 if it were available.
A couple things to keep in mind:
But, to the subject at hand - I wouldn't avoid a BB90 Madone, but all things equal, I'd take a T47 Madone over a BB90 Madone. That said, I'm price sensitive enough that I'd totally jump on discounted Madone with BB90 if it were available.
A couple things to keep in mind:
- BB90 isn't exclusive to the Madone - it's on my Domane and it's on Emondas, too, so feel free to look for feedback from owners of those bikes, too. FWIW, no troubles with mine, though I'm only a year and a half in.
- Trek has a lifetime warranty on the frame for the original owner. Hell, I'm going to start working on my sprint in *hopes* that my BB becomes irreparable shortly after 2019 stock is cleared out - I'll gladly take a 2020 T47 as a warranty exchange.
#48
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My LBS is having a good deal on the outgoing MY19 Madone line. I've wanted an aero bike to add to my stable, and the few test rides of the Madone have been fast and comfortable. Not noticeably moreso than my TCR, but I'll admit it: aero bike profiles just look sexy to me. It's a totally different aesthetic to me, even if it doesn't improve my top speed in any meaningful way (and it likely won't, the TCR is a weapon).
Obviously before I jump in to a purchase this big I'll do a deep dive for research. Which brings up the BB90 and its penchant for creaking. Apparently due to the fact that the tolerances can vary where the bearings contact the frame. Makes sense. I believe it's "a thing" because enough of it is out there on the internet, not just from owners, but also third party companies that offer workarounds or solutions.
However, every cycling site (GCN, road.cc, bikeradar, etc.) fail to ever mention the BB90 issues. They sing the praises about the bike's virtues. And even most owners who post about the creaking still say the bike rides great.
I did a search here at BF and yes, we have testimonials here as well. But not a ton. So what I don't know is:
1. Are there not so many complaints because not a lot of people on BF own Madones?
2. Are there not so many complaints because BF has a lot of Madone owners, but the rate of creaking issues is low?
3. If #1 - are BF members steering clear of Madones because of the BB90 issue?
I'm thinking of deciding by this weekend, but wanted to hear BF's collective experience and wisdom on this topic.
And yes I know there's that rumor that Trek may move to a T47 bracket, but I'm not factoring that into the equation right now.
Thanks for any advice and help!
Obviously before I jump in to a purchase this big I'll do a deep dive for research. Which brings up the BB90 and its penchant for creaking. Apparently due to the fact that the tolerances can vary where the bearings contact the frame. Makes sense. I believe it's "a thing" because enough of it is out there on the internet, not just from owners, but also third party companies that offer workarounds or solutions.
However, every cycling site (GCN, road.cc, bikeradar, etc.) fail to ever mention the BB90 issues. They sing the praises about the bike's virtues. And even most owners who post about the creaking still say the bike rides great.
I did a search here at BF and yes, we have testimonials here as well. But not a ton. So what I don't know is:
1. Are there not so many complaints because not a lot of people on BF own Madones?
2. Are there not so many complaints because BF has a lot of Madone owners, but the rate of creaking issues is low?
3. If #1 - are BF members steering clear of Madones because of the BB90 issue?
I'm thinking of deciding by this weekend, but wanted to hear BF's collective experience and wisdom on this topic.
And yes I know there's that rumor that Trek may move to a T47 bracket, but I'm not factoring that into the equation right now.
Thanks for any advice and help!
I agree that we ought to standardize BB's to T47.
#49
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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.
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