New bottom bracket but don't think its the right one.

[stegraham159]

Hello all.

Need advice please.

Own a 2012 Specialised Allez Sport and just this weekend had the bottom bracket replaced. It had a BC1.37x24 Road BB in it but it's been replaced with a SM-BB51 Mountain BB. Now the shop that did this said the crack set would be stiff for a few miles so went on my way. Been on the bike today and its very stiff. It wont even turn freely. Once I stop moving the crankset it stops. Also it squeeks.
Am i right in thinking that this is the wrong BB fitted to my bike?

Ste

 

[paulyboy90]

I'd say incorrect bb may also have been over torqued when fitted

 

[stegraham159]

Wasn't happy full stop and the squeaking has got worse over the day. (Use it a lot to bike round camp). So I've removed the crankset and had a look at the BB and I can see inside that the BB to the plastic cylinder inside and it looks like its bent and contorted. Not happy. Very shabby work. Emailing the shop that replaced it soon.

 

[accountantpete]

Just for reference - road bikes normally have a BB width of 68mm. MTB bikes have a BB width of 73mm.

You can get away with using an MTB BB on a road bike by using spacers. If you leave the spacers off and tighten up then the plastic cylinder will stop the cups from tightening up all the way unless you damage the plastic ...

 

[hoski]

As has been mentioned - you can use a MTB bottom bracket as a replacement for a road bike and vice versa. I believe you should reuse the plastic cylinder from the old BB, otherwise you end up damaging it as @accountantpete says.

Based on that, I would say your problem is that it has been badly installed - take it back to the shop and request a road BB to be installed correctly FOC. It simply isn't up to the expected standard of work.

 

[stegraham159]

Got it squared. Took it back to the shop and fixed it FOC. No more bloody squeaks. He has left the MTB BB on there but I've learnt how to replace it myself so will change it back to a road one when I have time and the tools.

Cheers for the replies guys.