Trek BB90 question
 

I've got a Trek with BB90 (2015 Boone). The NDS bearing is shot and I thought it was a good opportunity to upgrade to a thread-together BB (similar to a Token Ninja).
https://cimg8.ibsrv.net/gimg/bikefor...40f4aa086a.jpg


Popping out the existing bearings was easy, as was removing the BB sleeve. So far so good. Cleaned the shell real well but when I went to put in the new thread-together BB, it's obvious that the OD of the threaded sleeve is too big and it will not go into the BB shell. It's not close; the BB threaded sleeve is 37mm but the shell ID is ~30mm.

I'm wondering whether there is another piece that I need to remove from the BB shell in order to install the BB? Obviously this is no issue for OEM (in my case, GXP with the press fit bearings) or even running a crank with 30mm spindle, but has any other Trek owners needed to remove anything else besides the old bearings and sleeve in order to install a thread-together BB?

Why does your BB90 say "BB86"?

Did you leave the outside races in place?

This is a replacement (conversion?) part that substitutes for BB86, BB90, BB92. Apart from the threaded sleeve not fitting my shell, it looks like it would work to convert my press fit bearings to thread in bearings.

I am wondering if it's as simple as needing to remove some additional parts from inside the shell; when I took it apart it did not look obvious that there was anything else that's removable. The bearings press against the race that's part of the frame itself, but the are are some additional "steps" further inside the shell that step down to 30mm, but I can't tell if they're bonded in or if they're removable. I've watched several videos on YT for a similar upgrade process (press fit BB90 to a threaded Token Ninja) and from what I've seen, all they had to do was pop out the bearings and sleeve and there was nothing else to remove. But the Token part does seem to have a smaller OD threaded sleeve.

Thought I'd check here before I start hammering away at something that may or may not be a removable part.

Ok so after some more research I realized the BB I bought is for 41mm frame shells and I need a BB that's 37mm. I'll give that a try and see if that does the trick.

As I recall, BB90 Treks are just a shell that accepts bearings, and that shell pinches in to stop the bearing from going too far into the frame. Kind of like the removable clips do for BB30. Neither is like PF30 where there is a lip on the bearing assembly that catches on the outside of the frame.

So I would say that the 30mm part is built into the frame to stop the bearing. If not, the maker of the aftermarket BB90 assembly ought to have instructions that reflect how to remove the inner section.

Don’t forget bottom brackets are defined by Diameter and their Length
Be sure to measure the width of the bare frame.

Barry

lol,

I have generally positive feelings about Treks, but BB90 was one of their worst ideas ever. Thank goodness they're basically retiring it. I don't really recommend anything aside from quality bearings installed with a good retaining compound with these. If your fit is significantly loose, Trek does sell a bearing that's oversized. Other than that, they're designed to fit a 2437 bearing directly into the frame--there's basically no room to fit anything else in there without compromising the bearing in some way. Also, TBH, GXP is a poorly designed system that places particularly high off axis loads on the NDS bearing. I wouldn't say anything is out of spec if your NDS bearing is dying after 9 years--that's pretty good honestly. If you'd like better life, aside from good quality bearings, go for a crankset that uses a non-stepped 24mm shaft, like Shimano.

Yup, pretty much 🤣😅

My dumb ass got the incorrect BB. It's my own mistake but the mfgr certainly added to the confusion with their product labeling. I guess I shouldn't have assumed that BB86-95 isn't inclusive of BB90 due to the different shell diameter 😮‍💨

I understand I really just need new bearings (and technically just the single bearing to replace the NDS that's grinding) but I want to mitigate against future occurrences with the thread-together kind. I now know what my options are (single 3724 bearing or the Token 3724 thread-together), just haven't gotten around to ordering anything yet.

Oh yeah, there is a lot of confusion with all the different pressed in BB "standards", not to mention that pressed bearings don't make a lot of sense for a BB. I would be mad at it, except it makes us a lot of money, not e-bike repair money, but not far behind.

This to me is why no bike I own, and ride will ever have anything but a threaded BB. I suppose that could change if they invent something better but so far they have not at all. My shimano external BB have never worn out. I have over 50000 miles on my Habanero 6800 Shimano BB. Trek really messed up with this and really had they simply retain the original thread BSA the frames and bikes would still be super light. They saved nothing and cause riders a royal pain in the ass.

Sorry rant over

tFUnk - Any update on this? I am kind of curious if converting to threaded would work...

I think pretty much only Token makes this conversion BB and I got caught in analysis paralysis between getting one for $73 (with install tool) and just getting replacement 2437 bearings for $15. Since I'm going on an overseas trip in a few days I will decide after I come back in a couple weeks. YouTube videos indicate the Token Ninja BB should be a worthwhile update, though.

Thanks...let us know how it goes.

I just bought a 2017 Trek with BB90 and I have my eye on it. The drive-side is now slip-fit, instead of press-fit. I read extensively about how to best deal with the situation and decided to go with reinstalling the original bearing with a retaining compound. Seems OK but I only have a few miles on it...so time will tell...

I'll be interested to see how they made a male and female threaded section smaller in diameter than the 30mm holes in your BB, yet bigger in inner diameter than the 24mm spindle.

Ferguron will do and good luck!
Kontact Token makes a part that's specific to the Trek BB90 and there are multiple review videos of the product including the install procedure, albeit with other Trek frames and not the Boone specifically; I too am curious as Token does not list the OD dimensions of the threaded barrel that goes thru the shell. So apart from me purchasing the incorrect BB initially, I think my concern about the inner race shoulder of my frame may still be a valid one.