On Wednesday, May 13, 2020 at 9:22:16 AM UTC-7, wrote:
On Wednesday, May 13, 2020 at 8:26:47 AM UTC-7, jbeattie wrote:
On Wednesday, May 13, 2020 at 7:46:01 AM UTC-7, wrote:
It appears that the Trek Factory is taking over the Trek stores of at least a great many of them.

I had the "Dreaded BB90 Problem" (BB bearings are slip fit instead of press fit) and called the local private Trek shop and they had no clue about it since they deal with so few top-of-the-line Treks which are the only one's that have a BB90.

So I called the also local Trek Factory shop. The phone nearly rang off of the hook before they answered it. Talking to them the guy admitted that he was new and didn't know much about BB90 (and won't have to for herein out since Trek has converted to T47 bottom brackets which come in two varieties - internal and external though it is rather stupid way of labeling them since both have external screw-in cups. One is a wide BB into which the cups screw all the way and there is also an external cup that screws into the narrower and smaller diameter aluminum frames. It adds about an ounce to the Madone etc. frame but forever ends the creaking and clicking of bottom brackets that Trek started and most of the other CF builders copied on their top of the line frames. This has the advantage of making most of the Treks using the same two CC cuts and fitting the same Shimano cranksets.

In any case he told me that the Trek store in Livermore had the BB90 expert that could fix the BB permanently. I doubt that since I intend to keep this bike forever and the Trek factory uses Chinese bearings which are not, shall we say, long lived.

It would be nice to use Japanese bearings which are so much better than anything else that they aren't even in the same category. I looked around but they don't seem to make the size that a BB90 uses.

So when they open up I will have to take the Trek in to have the bottom brackets replaced with the specially oversized Trek BB90 bearings.

What is funny about it is that they aren't "special" at all. Chinese bearings have really loose tolerances and all they are doing is specially selecting the Chinese bearings with the widest possible OD (37.1 mm instead of 37 mm). If they are still too loose, they use a special Locktite to take up the slack.

It would be very nice if you could replace the BB90 with a push-in metal casing but if you did the bearings would be ridiculously tiny. And you cannot make them wider (use rollers instead of balls) since the BB is as wide as the Crankset is now.

So it is pretty plain why Trek is changing to a heavier bottom bracket but that doesn't help me and as I say, this and the Emonda and the Colnago CLX3.0 and the Lemond are my final bike purchases for the end of my life. So I need to get what I have working. I should probably have bought the same year of Madone that was a 6.2 which has a different seatpost and was fitted with the necessary holes to install Di2. But that is past and this does give me a chance to compare the manual shifting Dura Ace 9000 group with the 9000 Di2.

Wow. What an epic. Why don't you buy the 37.1 bearings and press them in. https://www.enduroforkseals.com/prod...BB90HT2CS.html Hit "add to cart" button.
Or some standard bearings and Loctite 638. https://wheelsmfg.com/bottom-brackets/trek-bb90-95.html Fifteen minute job. Five more for installing the crank. If the BB is still OS, send the frame to Trek for repair -- which they will do.

Thanks for the Arizona people. The Locktite 638 is the retaining compound and if there is any play in the bearing you have to use another "filler" type of Locktite the number of which slips my mind.

638 fills gaps to .25mm. https://uk.rs-online.com/web/p/retai...ounds/8211425/ If 37.1mm bearing does not work, there is no such thing as a 37.2mm bearing, unless you have it custom manufactured. Standard is 37mm.


But I suspect that this frame had a creak and they already used the 37.1 bearing and all I'll have to do it press fit the larger bearings.

Again, what larger bearing? If you get to the point where 37.1 doesn't work, your options are a Loctite-like filler/retaining compound (many on the market) or a repair.


Remember that using Locktite is not something that you would usually do with something like a press-fit bearing. It was designed for holding screws from loosening. If the bearing should need replacing in the future it can enlarge the hole pushing it out and taking part of the finish with it.

I use Loctite 609 on my BB30s. Made for press fit applications, although I've used it most frequently on aluminum BBs, I don't have any reason to believe it would hasten the death of my CF BBs. I used it on the Roubaix CF BB now used by my son, and it has produced a silent BB, and he's a watt monster. Never had removal issues using Loctite 609.

-- Jay Beattie.