Cup/cone to square taper BB.

Eddy32

Might be a simple question but,

If a cup and cone spindle measures 120mm, is there/it possible to use a 118mm BB with spacers 1mm on each side?
Someone with the same bike said "122.5mm was to big".

It's a cheap bike and uses a 120mm cup/cone BB, and a "prowheel jazz" crankset, the crankset is bent and the bearings are clicking/crunching while peadling.

I would like to replace it with a shimano un55 63x118mm BB?/ Shimano Acera M361 crankset.

Is this possible/ any ideas?

The Rookie

To can't use spacers, no.

You need the axle to go with the new crankset, what axle worked with the old one is irrelevant as they have different offsets of the rings from the mounting on the axle.

Check the specs for that Acera crankset but it almost certainly will want a 122/3mm being Shimano.

Eddy32

So if replacing the crank with the Acera M361 lists "Spindle Length: 122.5mm".
Would make the old/current BB 120mm spindle length irrelevant?
Other words buying the Replacement Crank with Spindle Length: 122.5mm would mean I also buy a 122.5 BB, and the chain line should be fine?

Thank you for your time.

cooldad

Yep, axle length has to match the new crankset.

Eddy32

cooldad wrote:

Yep, axle length has to match the new crankset.

Thank you.