Putting some new second hand Ultegra cranks on the tripster.

Had a new ish but used HTII BB lying about so put that on. Cranks turn (but wont spin!) so obviously very tight.

Does a road BB differ from a MTB one or is this one just borked?

Thanking you in advance of the LBS opening!

I think they do differ but I thought road ones were a bit wider
Could try taking out the spacer (if you have one in) but I’d buy proper

I understood they were identical apart from the road ones had a shorter threaded section.

I’ve got both at home I can measure, but you’ll probably have an answer wby the time I get there.

One thought: Did you employ a gorilla to tighten up the preload washer?

defo the BB is tight. off to get sorted now so that I can ride in the hills later!

good old LBS – free BB sorted. Transpires the one I had was borked. Spinning nicely now!

Happy days. Did they say if there was any difference between road and MTB?

don’t think so apart from what was mentioned above. just one of those things it seems!

Shimano road cups are fatter than the MTB cups and have a shorter threaded section – the MTB cups are designed to take the spacers needed to accommodate 68mm and 73mm shells.

The cup width is only a small difference though, one which you might not even notice when fitting it all together and can dertainly be jiggled with some creative spacer. I’ve run MTB cranks on road cups with no problems. Just be aware that you might well have less thread in the shell than with MTB cups.

MTB cups are 1mm thinner than road ones.