BB compatability XTR & 105 hollowtech - much of a muchne

BERGS2

Hi All - just got a replacement BB from LBS - was XTR but have got a 5600 105 hollowtech replacemment.
On getting out the XTR cups and inner sleeve they seem to be about 5mm longer than the replacement 105 ones. i.e. when fitting the unit together outside of the bike the 105 looks smaller.

is this likely to cause issues?

the XTR had 5mm of spacers he drive side & 2.5 on the non drive

The BB is fitted in a 68mm shell..

cheers all -

p.s. what are the opinions on facing prior to fitting? looks like a waste of money to me - surely the previous would have been lined up just fine...?

cooldad

Why buy a road BB for a MTB?

ride_whenever

Bit of an odd one, however BB are much of a muchness and I'm sure you wont notice any worse sealing until bad weather kicks in again.

If the shell hasn't been faced (and just because the old one was on there is no guarantee) then I'd get it faced as it does make the bearings last better.

nicklouse

you have noticed the difference the width of the drive side cup.

as road bikes do not use spacers they have less thread. A road BB on an MTB can be used but you will still need to use the spacers that were on there.

the shell needs to faced once for external BBs unless it is damaged or painted where it will need to be re faced.

BERGS2

cooldad wrote:

Why buy a road BB for a MTB?

coz the chap in Evans said it would do the job....

it's only the size differential that has me a little concerned...

nicklouse

well it will do the job, but i would not leave it in there for long.