GXP BB90 and the wave washer
03-29-20, 05:24 AM
#1
Senior Member
Thread Starter
GXP BB90 and the wave washer
OMG, not yet another BB issue/question.
It's been suggested to me that I don't need to have a wave washer on GXP BB90 drive side between bearing dust cap and spider.
If the wavy washer is removed and the crank set is installed/torqued there is in fact a slight gap between the drive side bearing cap and the back side of the sprocket/spider.
In general this seems fine and preferable, however, it seems to me that over time, considering the way GXP clamps the crank to both sides of the non drive side bearing, that the crank set will eventually begin to push
the NDS bearing out of it's cup. Especially when cranking very hard on climbs. Essentially moving the entire crank set over thus changing the chain line etc.
Even if the NDS bearing was very tightly pressed in and/or retaining compound used, the tendency would be that the NDS bearing would be pushed out by the distance between the spider and the drive side bearing cover.
I seem to find varying info around... e.g. "yes, wave washer is needed", "no, wave washer is not needed".
I was curious if anyone may have first hand experience with this... THANKS!
It's been suggested to me that I don't need to have a wave washer on GXP BB90 drive side between bearing dust cap and spider.
If the wavy washer is removed and the crank set is installed/torqued there is in fact a slight gap between the drive side bearing cap and the back side of the sprocket/spider.
In general this seems fine and preferable, however, it seems to me that over time, considering the way GXP clamps the crank to both sides of the non drive side bearing, that the crank set will eventually begin to push
the NDS bearing out of it's cup. Especially when cranking very hard on climbs. Essentially moving the entire crank set over thus changing the chain line etc.
Even if the NDS bearing was very tightly pressed in and/or retaining compound used, the tendency would be that the NDS bearing would be pushed out by the distance between the spider and the drive side bearing cover.
I seem to find varying info around... e.g. "yes, wave washer is needed", "no, wave washer is not needed".
I was curious if anyone may have first hand experience with this... THANKS!
03-29-20, 09:02 AM
#2
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I've got a lot of first-hand experience with owning GXP crank/BB's and installing/servicing them since their inception in the mid 2000's. Depending on the BB whether it's a threaded cup type, or in your case a BB90 where the bearing sits directly into a carbon frame, I like to go a couple different routes. On a BB90, the main potential issue is the non-drive side bearing migrating out of the frame. Since the wavy washer can easily compress, I don't really like using them on a BB90 because, under load, the spring can compress enough to allow the NDS bearing to migrate out. I like using Delrin spacer shims instead. Wheels MFG sells them in .5mm widths. It takes some experimentation to get the spacing right, but I like to use just enough to fill the gap, but not enough to put a noticeable axial load on the drive side bearing.
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03-29-20, 10:18 AM
#3
Senior Member
Thread Starter
I've got a lot of first-hand experience with owning GXP crank/BB's and installing/servicing them since their inception in the mid 2000's. Depending on the BB whether it's a threaded cup type, or in your case a BB90 where the bearing sits directly into a carbon frame, I like to go a couple different routes. On a BB90, the main potential issue is the non-drive side bearing migrating out of the frame. Since the wavy washer can easily compress, I don't really like using them on a BB90 because, under load, the spring can compress enough to allow the NDS bearing to migrate out. I like using Delrin spacer shims instead. Wheels MFG sells them in .5mm widths. It takes some experimentation to get the spacing right, but I like to use just enough to fill the gap, but not enough to put a noticeable axial load on the drive side bearing.
