Just replaced the SRAM Rival bb in my cx bike, like for like swap. Are they all very stiff straight out of the box?
I think it’s fitted ok, although there were no instructions with it, but the cranks won’t do a full revolution if you spin them. Is this normal? Will it loosen up with a bit of use?
sounds like you've over-tightened the bearings - the tightener-thingy should only be lightly done up
No I think they should spin freely. I had this issue recently; I'd fitted the wrong spacer (too wide) on the DS and when I replaced it, cranks spun freely.
Perfectly normal, it'll loosen up after a few miles then fail completely after about 150.
This is normal for sram bottom brackets.
More helpfully, which interface is it? Gxp or dub? Do you have any wavy washers that were on the crank back in place?
It shouldn't be stiff, sounds like maybe a spacer is missing, there are varying spacer configs depending on shell size ect. You should be able to find the manual on srams website.
I've just fitted a dub BB for the first time.... It was super stiff like you said.
Removed the space between the BB cups (that sits inside the frame) and the cranks spin fine. Somehow it was interfering with the crank axle.
Perfectly normal, it’ll loosen up after a few miles then fail completely after about 150.
This is normal for sram bottom brackets.
Excellent then I can swap it out for a shimano set and not get rinsed when buying chainrings again!
It’s GXP and a 68mm bb shell so the big spacers aren’t used. As far as I can remember all the washers went back.
I will check torques and then see how it does after a decent spin.
it’ll loosen up after a few miles then fail completely after about 150.
This is normal for sram bottom brackets.
2,100 miles on the DUB bb that came fitted to my Spur and its still going strong.
I think they fail early due to incorrect fitting, or the British weather.
It’s GXP and a 68mm bb shell so the big spacers aren’t used. As far as I can remember all the washers went back.
Check the wavy washer, that's the usual problem with gxp.
Next time fit a Shimano BB with a top hat instead of a third party BB. I like sram kit but they seem incapable of making things with bearings that last.
I used to love sram double tap on my road bike but I just couldn't get used to their bb and Chainsets.
I now run shimano on everything due to the 24mm spindle and hope bb combo that just works and is quick and easy to install and maintain.
If its stiff on installation then it could be any of the above or bb alignment.
Were there any signs on the bb you took off or on the Chainset you removed? How long did the previous bb last?
Is one side of the bb stiffer than the other or just when the crank sits on both bearings?
Out of interest, what frame is it?
I like sram kit but they seem incapable of making things with bearings that last.
I've just replaced a SRAM DUB BB that was fitted in Nov '21 and has done 5500 (or thereabouts) kms. On an Enduro as well, so not had an easy life. For how cheap they are relatively, that seems ok to me.
Were there any signs on the bb you took off or on the Chainset you removed? How long did the previous bb last?
Is one side of the bb stiffer than the other or just when the crank sits on both bearings?
Out of interest, what frame is it?
The previous bb did a couple of years of fairly regular (most weekends) cx riding and little love! It was fairly shagged when I came to remove it - like you could really tell it was really shot.
The new bb seems uniformly stiff. It’s a Planet X xls. It’s been used hard for years up until spring this year when I basically gave up on bikes for six months, now I’m trying to get some mojo back but foolishly tried to do some maintenance first.
I find new sram bbs start a little draggy initially but only when you spin it by hand. They’re fine after one ride.
GXP bearing preload has no adjustment - it’s just done up tight and has a wavy washer in it from memory. As long as you have the right spacers in there there’s nothing else to do / adjust.
Ive found Sram gxp bbs go quite rattly after a while - I’m using a Praxxis gxp one instead on my mtb at the moment and it seems to be lasting longer / staying smoother. Was only £27 so wasn’t wildly expensive.
On replacement chainrings I wouldn’t say Shimano are particularly cheap either. Double chainset chainrings always seem ludicrously expensive to me.