How stiff should BB30 be?

mortimer2000

I've recently bought a secondhand bike with bb30. With the chain off there feels like there is a fair amount of resistance and if you push the pedal with your hand (no chain attached) the crank doesn't spin freely for very long at all. With my older bikes the crank would always spin freely for a long time. Do I need new bearings or is it simply the way the bb30 is? I've taken off the crank and the bearing feel quite stiff but smooth with none of the creaks or noises I've heard about.

Thanks, Mortimer.

drlodge

BB30 is just the way the bearings are located (interference fit) and the dimensions of the bearing/spindle assembly. Sounds like the bearings to me, although if the interference fit is really tight, it could possibly squeeze the bearing internals.

Replacement bearings are cheap enough, getting them swapped over is more tricky.

keef66

I don't think it's confined to BB30; most of the recent outboard bearings suffer from drag because of the seals. As long as it rotates smoothly I'm sure it's fine.

drlodge

Ah yes, seals. Could be the seals in the sealed cartridge bearings...

sungod

with the crank off, without removing bearings you should be able to remove the outside seals and look at the condition, use a pick to carefully remove the seals, if the bearings are dirty/dry, time for a clean and/or grease

jgsi

I would prepare to disassemble ... have some new bearings ordered off Ebay or wherever... or get a bearing kit from Wiggle that has a few more shims. the wavy washer on the ND side is supposed to be fully preloaded.. and this depends on the number of plastic shims you use... no rule of thumb it is .. if you have a non freely spinning crank, you may need to add or even take some away.
The crank should be solid but able to spin around a bit.. you'll know when it feels right as it doesnt at the moment.

Old_Timer

JGSI wrote:

I would prepare to disassemble ... have some new bearings ordered off Ebay or wherever... or get a bearing kit from Wiggle that has a few more shims. the wavy washer on the ND side is supposed to be fully preloaded.. and this depends on the number of plastic shims you use... no rule of thumb it is .. if you have a non freely spinning crank, you may need to add or even take some away.
The crank should be solid but able to spin around a bit.. you'll know when it feels right as it doesn't at the moment.

This, and watch the amount of tension that is put on with the pre-load adjuster also. Getting everything cleaned well and quality bearing cartridges that you install correctly will determine whether the BB lasts and doesn't make noises. The bearing and washer kits are not really expensive, shop around a bit at the bicycle shops and on line for your best price. Be sure you grease the seals well so they don't drag on the spindle when you assemble things, it makes a big difference in how things feel.