MRC bb - anyone put one in?

[nathanman]

I'm having issues with the MRC bottom bracket on my ti :cry: the axle is moving from side to side which would normally mean it is fubared but having taken the crank off I'm not sure it is. The MRC BB'S appear to use spacers and a circlip to keep the axle in the correct position, the black plastic spacers appear to be the same width each side and they sit against the circlip which is in a central groove on the axle. The drive side cup has a double cartridge bearing and the non drive has a single one, these bearings butt up against the spacers to keep the axle in position. it appears that the non drive side cup should have another spacer or bearing to stop the axle moving but having only dealt with external bb's and shimano ones like the un72 im not sure.

Anyone got any ideas?

 

[GT-Steve]

If it's the one in the McTi? I put it in... :?

And as far as I can remember (a lot's happened since) it was no different from a conventional bb. But I don't remember stripping it down to inspect how it's assembled.

Someone on here has one for sale (can't remember who). If you can locate it, they might be able to help... ?

 

[nathanman]

If it's the one in the McTi? I put it in... :?

And as far as I can remember (a lot's happened since) it was no different from a conventional bb. But I don't remember stripping it down to inspect how it's assembled.

Someone on here has one for sale (can't remember who). If you can locate it, they might be able to help... ?

It is that one matey, I've never had a conventional bb out so don't know what's what with them . The cranks are moving side to side and rubbing against the bb cups.

 

[GT-Steve]

:shock: :shock:

That doesn't sound right...

 

[RockiMtn]

here's what i got. left cup has one bearing cartridge, right side has two.

thin sleeve spacer, long sleeve spacer, c-clip secured groove in the centre of axle, medium sleeve spacer, and thin sleeve spacer. when put together, cups make contact and there's little to no left/right play in axle.

 

[pete_mcc]

I would check that the circlip is still strong and sitting within the groove. Once that dies then the axle will be able to move at will no matter how many spacers or bearings you have. It's probably the only explanation if the BB has previously been fine.

 

[nathanman]

Thanks for the info guys, the circlip on mine seems fine but the spacers in mine are the same length both sides which is probably why its moving. I've just given it a lube and clean which is why the side to side movement is possibly more apparent. Gt Steve has sent me a spacer that may have come from my bb or maybe a litespeed one. I'll fit it tomorrow and see what happens.

 

[silverclaws]

Do you not glue the axle into the bearings, for there is a glue for assembling shafts into bearings, helpful when there is a bit of wear in the shaft, but otherwise is sort of helps stop things sliding with the transition fit. But when the assembly was put together was the shaft cooled and the bearing warmed , the expansion of the bearing with heat and the contraction of the shaft with cold then fit them and let atmospheric temperature sort the metal out ensuring a tight fit ?

 

[nathanman]

Do you not glue the axle into the bearings, for there is a glue for assembling shafts into bearings, helpful when there is a bit of wear in the shaft, but otherwise is sort of helps stop things sliding with the transition fit. But when the assembly was put together was the shaft cooled and the bearing warmed , the expansion of the bearing with heat and the contraction of the shaft with cold then fit them and let atmospheric temperature sort the metal out ensuring a tight fit ?

I've never heard of glue being needed on a conventional bottom bracket but as I don't have much experience of fitting them I could be doing it wrong :?