My CX bike that I use as a commuter has a weeny little bit of side-to-side play in the cranks. It's a Shimano HTII BB / Tiagra compact chainset that when I've taken it all apart seems in very good shape - no sign of the BB being shot, for example, but even after cleaning and regreasing everything, when I put it back together, the play remains.
Any bright ideas? The BB was fitted flush to the frame - no plastic spacers on the drive or non-drive side. Would adding a thin spacer to the non-drive side work?
Thanks in advance...
You have to tighten the bearings using the funny plastic finger tool thing.
missing spacer. crank cant go any further onto the splines so you get play.
thanks for the advice - the finger tool thing is nipped up, but there's still play, hence the feeling it's a spacer thing? Drive or non-drive though?
what size bb shell have you got?
NO spacers? Should have
68mm- one spacer on N/D/S, two on D/S.
73mm-no spacer on N/D/S, one on D/S.
It's a 68mm shell, anjs...
Shimano Tech Docs seems to be down at the mo - I was wanting to check what I think you might be thinking... (I hope)!
Munque-chick - great minds think alike!
I don't know for sure, but I think that's for a triple on an MTB isn't it? My S-Works Roubaix has none at all, as far as I can recall? Properly confused now! Might go and rummage and see if my instructions from the new Dura Ace BB for the S-Works are kicking around somewhere in the garage...
Just found the destructions for fitting the DA BB from the Roubaix and that's got both 68 and 70mm listed as suitable width BB shells.
Therefore... if the CX bike's a 68mm shell, sticking a 2mm black nylon shim on the non-drive or drive side should work shouldn't it? And if so, which side...?
Cheers (again) for your help...
gone...yes I am thinking for MTB's. I would put it on the drive side if only because I'd be concerned the rings would foul on the chainstay with the spacer on the other side.
no spacers.
if there's a tiny amount of play I'd check the cups are tight in the frame, otherwise it's new bb time.
I once forgot one of the spacers when installing a BB. There was no play in the cranks but you could push the axle a few mm each way through the BB shell which upset the front shifting.
I think if your cranks are wobbling the BB bearings are on their way out.
There should be NO spacers in a road BB, are you sure everything is nipped up tight and it's not play in the pedals that you're feeling?
Pedals are fine, defo side-to-side on the axle sadly, but the bearings feel ok? What I can't understand is that the DA instructions say it's suitable for 68 and 70mm shells - there must be times when you have to put a spacer in then?
I'll got check it again... thanks for all the advice though - really appreciate it.
I had a very similar problem recently on my MTB. Bought a chainset s/h. whether it was a bit knackered already, or whether I somehow c*cked up the installation, after a little while there was a bit of play in the non-drive side crank. Eventually, it actually came off whilst i was riding, luckily not too far from home. Turned out that the splines on the crank arm were worn away, and weren't holding the crank on no matter how tight the pinch bolts/preload cap were done up. Seemed to give a bit of side to side play like you mention, maybe check that there's still a decent amount of "tread" left in the splines
Right - just stripped it all down again... and I think it's going to be ok. I think I might have not been putting enough preload on, and also not had the cranks / axle fully butting up against the cups. Good bit of grease on there and nicely nipped up and it's as good as I could hope - and no spacers!
Thanks for all the advice. I'm looking forward to the long commute now tomorrow 😈 but not the one home in the rain...
it's suitable for 68 and 70mm shells
A 70mm shell is an Italian threaded BB - the cups are quite different. Different thread and both sides are RH thread (so ignore it basically!)