Threaded GXP BB Question

pkovo

Well-Known Member
#1
A used frame I recently bought came with a threaded GXP BB and GX Cranks. While working on something else, I noticed I have a small amount of play in the BB. I took it apart, regreased everything and retorqued it, but still get a very small amount of play. Actually, i did that twice, and couldn't eliminate the play. It is very slight though, and i don't actually notice it while riding, just when I grab the end so fthe crank arms and push/pull on them. Upon disassembly the only oddity I noticed is the non drive side dust cover was on backwards, which I corrected on reassembly.

Having never had a bike with this BB/Crankset, I was surprised to find the way it assembles it really one fastens the crank on one side, between the bearing and the step-down on the spindle, and the other side kind of "floats" for a lack of a better way to put it. I was most surprised to find on the drive side there is a plastic "dust cover" that has a sleeve that slides between the bearing inner race and the spindle. To me that seems like a likely place for failure and possibly the source of my play....Its just plastic and seems kind of inprecise. Anyway, my questions are:

Are these known to be problematic? Anything obvious I am missing? Is a new BB likely to be all that is needed?

I was going to just grab a new BB today on my lunch break since they are quite cheap, but this whole design left me feeling a little unimpressed so I hesitated. I have a set of Race Face Turbines currently sitting on the shelf that i could repurpose to this bike instead. Would just need to buy a new chainring for them. Color will stand out, but if it works, I don't really care.

Trying to gauge the better option and hoping someone on here that does more wrenching than I might have some insight.

Thanks!
 

stb222

Love Drunk
Jerk Squad
#2
Try a new BB and then figure something out if it doesnt work. Threaded GXP are really common and typically dont have a lot of issues.
 

pkovo

Well-Known Member
#3
I found the pic below online. It shows the part that seems odd to me. That sleeve slides between the spindle and bearing. Who knows, maybe when all the parts are new and fresh this works great, but it seems like a weird design to me.


sram BB.jpg
 

qclabrat

Well-Known Member
#4
SRAM is 24mm on the drive side of the spindle and 22mm on the NDS. need either a SRAM BB or an adapter to reduce it to 22mm. GXP and Shimano are the same where it's 24mm thru out and does not taper like SRAM. I write this with no research on SRAM GX, which I've never used. It's my best guess since you mentioned play on one side
 

qclabrat

Well-Known Member
#6
SRAM is 24mm on the drive side of the spindle and 22mm on the NDS. need either a SRAM BB or an adapter to reduce it to 22mm. GXP and Shimano are the same where it's 24mm thru out and does not taper like SRAM. I write this with no research on SRAM GX, which I've never used. It's my best guess since you mentioned play on one side
disregard my post above, I'm not thinking clearly today.....
 

Ryan.P

Well-Known Member
Team MTBNJ Halter's
#7
Gxp is my favorite bb interface . My experience is that bearings will get tight over time from contamination so maybe the plastic spacer on the drive side got damaged and isn't as tight as needed . New bb ftw
 

pkovo

Well-Known Member
#8
Gxp is my favorite bb interface . My experience is that bearings will get tight over time from contamination so maybe the plastic spacer on the drive side got damaged and isn't as tight as needed . New bb ftw
Thanks, that seems quite plausible. That plastic spacer slides in and out very easily. I'm wondering if that wavy washer wasn't added after the fact to keep the ill fitting spacer from backing out.

Glad to here this are usually reliable, and liked, because slapping in a new BB would certainly be the easiest and quickest remedy.
 

Ryan.P

Well-Known Member
Team MTBNJ Halter's
#9
Thanks, that seems quite plausible. That plastic spacer slides in and out very easily. I'm wondering if that wavy washer wasn't added after the fact to keep the ill fitting spacer from backing out.

Glad to here this are usually reliable, and liked, because slapping in a new BB would certainly be the easiest and quickest remedy.
No wavy washer on any of my bikes , that plastic shield is tightly held in place when new . Inner bearing race has a groove and the plastic piece has a lip that it sits in
 

pkovo

Well-Known Member
#14
Even with new BB installed, there is still some
Play there. Its a very small amount. I cant feel it on the bike, but since I know it’s there, the ocd in me cant let it go.

The bearings, old and new, seem to fit a bit loose on the spindle. I’ll probably cut my losses and use a different crankset.
 

Ryan.P

Well-Known Member
Team MTBNJ Halter's
#15
that's odd all my gxp bb bikes are solid no play what so ever , wonder if the crank is not bottoming out on the non drive side when tightening ? lots of grease is your friend
 

jdgang

Active Member
#16
that's odd all my gxp bb bikes are solid no play what so ever , wonder if the crank is not bottoming out on the non drive side when tightening ? lots of grease is your friend
While I never was a fan of the gxp standard (no matter what I do the DS bearing always get crunchy quickly) they never had any play.
 

pkovo

Well-Known Member
#17
that's odd all my gxp bb bikes are solid no play what so ever , wonder if the crank is not bottoming out on the non drive side when tightening ? lots of grease is your friend
I thought about that. I tried a spacer on that side to take up any slack if that was the case, but it still had play.

Since its a rainy day, I may take one more stab at it later.