SRAM Wavy Washer Or Not?

[Eldron]

My son is a strong rider, broke a lot of things that normal riders would not. I tried everything to get it to stay on. Cleaning with solvent, Loctite, etc, nothing worked. Loctite did make it better, but still didn't solve the problem.

 

Is your son Robert Forsterman????

[love2fly]

If Shimano MTB tightens lik my road bike I agree, tighten the centre cap hand tight then tighten each pinch bolt sequentially until tight. Almost but not exactly like tightening 4 stem bolts. Mine stripped the heads so bought new high tensile at local eng. supplies shop.

That shouldn't happen if torqued correctly. A common Shimano crank mistake is to torque each bolt and call it done. Problem is that when you torque the second bolt the first one gets looser (as the gap narrows).

 

Tighten each one by hand 3 or 4 times then torque both.

 

I have never had a Shimano c´that I have worked on come off (unless there was an actual warranty problem).

[love2fly]

I chatted to Cape Cycles and apparently the wavy washer isn't required on the threaded GXP BB as the DS bearing has that plastic insert which protects the bearing.

HOWEVER when my bearings wore out (pretty good as I got one year out of them) I replaced with 24x37 bearings and not having that plastic sheield could be the reason.

What I cant remember is if the shield is exactly 24mm or or what that bearing (DS) ID was.

 

Think I'm in for either a new BB, go the CK route with adaptor and new BB or just close the disappointing Sram crank chapter and go with Shimano.

 

Looks like the DS bearing is merely a 6805 which is 25 x 37 x 7 as opposed to 24 x 37 x 7.

[DieselnDust]

Looks like the DS bearing is merely a 6805 which is 25 x 37 x 7 as opposed to 24 x 37 x 7.

thats correct. the plastic insert takes up the 0.5mm in radius difference

[love2fly]

Wonder if metal to metal is a problem? In OEM form they rely on the plastic to wear prompting BB replacement. Makes no sense. Being able to spend R260 on 2 bearings vx R800 on a new BB would be my preference

[DieselnDust]

Wonder if metal to metal is a problem? In OEM form they rely on the plastic to wear prompting BB replacement. Makes no sense. Being able to spend R260 on 2 bearings vx R800 on a new BB would be my preference

 

 

 

There can be a problem with metal to metal contact because the bearings are not a press fit as they are designed to be. Its a Transition fit to allow the axle to slide in which brinelling the bearings. The platics leeves make it easier to take up the fit without having to apply a really tight tolerance to the axle and bearing which would treble the cost.

The trouble comes when the bearing has a problem rotating when the roller bearing rotation speed does not align with the crank rotation speed and the bearing either slides or the rollers slide on their race. If the inner race slides on the crank axle it wears the axle. The plastic sleeves prevent the axle wear, hence I prefer the OEM BB's or Chris King

[TNT1]

The wavy washer is a variable lift washer can be used on GXP cranks PF or external BB. The spacers are a more accurate way of getting correct preload.

As un-technical as "wavy washer" sounds, when I slipped "variable lift washer" into Bing, it came back with a bunch of washing machines.

Edited April 23, 2021 by TNT1

[love2fly]

I'm wondering how I'm going to add "spin Cycle" int my next interval session!

 

 

As un-technical as "wavy washer" sounds, when I slipped "variable lift washer" into Bing, it came back with a bunch of washing machines.

[love2fly]

There can be a problem with metal to metal contact because the bearings are not a press fit as they are designed to be. Its a Transition fit to allow the axle to slide in which brinelling the bearings. The platics leeves make it easier to take up the fit without having to apply a really tight tolerance to the axle and bearing which would treble the cost.

The trouble comes when the bearing has a problem rotating when the roller bearing rotation speed does not align with the crank rotation speed and the bearing either slides or the rollers slide on their race. If the inner race slides on the crank axle it wears the axle. The plastic sleeves prevent the axle wear, hence I prefer the OEM BB's or Chris King

For now I have gone back to a stock standard (plastic insert into 25mm bearing) albeit used but greased OEM BB but WITHOUT wavy washer. have a new BB on order but will ride this until the new one is needed.