Do I really need to face the BB shell?

felix.london

Well managed to remove the BB (see previous post) and now it would be nice to do the whole job without having to go to the LBS.

I have an '06 Rockhopper and I'm installing a SLX dual/bash (and new SLX front mech & shifter)

Do I really need to face the frame? I guess it depends on the paintwork and general finish of the BB shell?

What about filing down to the bare frame and then using a digital measuring tool ( like this http://www.amazon.co.uk/0-150mm-Vernier-Digital-Micrometer-Measuring/dp/B0042S25T0/ref=sr_1_6?s=diy&ie=UTF8&qid=1332835692&sr=1-6 ) to check the BB shell is a uniform size all round?

Any good or not accurate enough?

nicklouse

i would and it will make it worse and take way too long and would not actually do what is needed.

see the topic in the FAQs.

felix.london

BTW - it doesn't mention 'facing' in the Shimano installation instructions (although it does on the Parktools website)

The Rookie

Facing is little to do with paint, much more the metal behind it, Face it, when your hopper was made external BBs were not really heard of, so I doubt the BB will be up to scratch.

nicklouse

felix.london wrote:

BTW - it doesn't mention 'facing' in the Shimano installation instructions (although it does on the Parktools website)

every shimano fitting info for external stated the BB has to have been faced.

felix.london

I guess "if you're going to do a job..." and all that

Seems strange that Shimano don't advise this on their installation instructions (or is it in their interest for you to knacker your bearings earlier? )

felix.london

"If the bottom bracket shell is not parallel, gear shifting performance will drop"

- Shimano 'General Safety Information'

DodgeT

felix.london wrote:

What about filing down to the bare frame and then using a digital measuring tool ( like this http://www.amazon.co.uk/0-150mm-Vernier-Digital-Micrometer-Measuring/dp/B0042S25T0/ref=sr_1_6?s=diy&ie=UTF8&qid=1332835692&sr=1-6 ) to check the BB shell is a uniform size all round?

Any good or not accurate enough?

A whole lot of hassle for after which, you may get a uniform size all round, but that wont necessarily mean that the face is square to the threads.

Just take it the shop. Or if you really don't want to, then don't. You may be lucky, you may not.

1mancity2

Do it!!!!

felix.london

Will take it down there this morning - hopefully he can sort it today

Cheers

nicklouse

felix.london wrote:

Will take it down there this morning - hopefully he can sort it today

Cheers

Morning! it is almost afternoon.

Damn cheese eaters.

felix.london

ha! Indeed..and if I'm not quick they'll be shut when I get there for a 2.5hr lunch break