On Sunday, August 9, 2020 at 4:14:56 AM UTC-7, wrote:
On Sunday, August 9, 2020 at 3:08:01 AM UTC+2, jbeattie wrote:
On Saturday, August 8, 2020 at 3:15:40 PM UTC-7, Tom Kunich wrote:
When I got my Trek Madone if became rapidly clear why it was so cheap.. The bearings in the BB90 were rather loose. Now there are several methods of fixing this - one is to use a strong locktite-type compound which locked the bearings in place and one is the Trek way which is to put an oversize bearing in place of the stock bearing.

With normal caution as an Engineer I chose the least damaging method first. I followed the directions on the locktite and glued the "just fits" bearing into place and allowed it to dry the requisite 48 hours.. Well, climbing one of the local hills last Tuesday the BB90 began to "click" in the same place every revolution on the drive side pedal. This means the glued drive side bearing has come loose. Inasmuch as I am presently working on the Colnago I won't look at this until later. Another choice has come up - that is to check the bearing that is presently in the Madone, to see if it is undersize. That might be the case since the bearings more easily obtained from Trek are Chinese and let's say they aren't the finest quality bearing available. Hambini of one piece BB push in bearing fame who hates BB90 also can supply NTN bearings which are exactly the right size. NTN is a Japanese bearing manufacturer that supplies the best bearings in the world.

So when I remove the bearing that is presently flopping around in there I can closely measure it if I can remember where I put my micrometers. Failing that I do have a digital caliper that is fairly accurate to two decimal places. If the bearing that is in there is undersized by any significant amount (which is common with Chinese bearings.) I will get the bearing set from Hambini and install those before going to the extreme of those oversize Trek bearings which are so oversize that they can distort the bearing cups. This screws up the bearing and generally causes premature failure though "premature" is sort of an undefined term that might mean it only lasts for 1,000 hours. Chinese bearings would probably only last for twice that anyway. NTN bearings virtually last forever under the sorts of loadings that the BB90 puts on them.

So presently I'm riding the Emonda and trying to go no lower than the 28 tooth so that I can get a little more training in my legs. I am presently at 80,000 feet of climbing when I would normally be at double that. I normally close a year off with over 200,000 feet of climbing. Judging from the way that my legs felt today after a couple of 900 foot climbs I don't think that I will make 125,000 but stranger things have happened.

You should also check the crank bolt torque and maybe swap the pedals out, check the chain ring bolts and even the rear QR before pressing in new bearings. Cyclical clicks can come from places other than the BB.

-- Jay Beattie.
Agree. I sure want to be sure that the bearing is the problem before I knocked that loctited bearing out.

Lou
To look at anything you have to pull out the crank. Generally in a BB90 if you have a loose BB bearing it comes out on the drive side crank. So it isn't as if it is a difficult analysis.