To face or not to face

paulneenan76

Hello All

Chain checker said new chain (got another SRAM pc 991) but may not get away with chain only and so I might need a new chainset/cassette. Can get a SRAM 997 for £20 and merlin are selling Deore LX HT2 chainset for £50 - so £85 all told for a new drivetrain (including new chain)!! The thing is, I'd like to attempt the job of removal/replacement myself, because I wanna keep the cost down and want to have that sense of achievement (or failure). However, is this a bit optimistic of me (I am not that mechanically minded)? I have the old truvativ crankset from my old Carrera Kraken (hence its old and probably stuffed) on the 73mm BB shell of my on-one 456 carbon - putting the new chainset on, will I need it faced? If so, is it worth taking the whole lot to my lBS for fitting?

Cheers

Paul

supersonic

Is worth doing, as the faces can be miles out. Peace of mind.

nicklouse

Every BB that came to me with a short life span had not been faced.

every frame i built and will build will have the tools applied to face or just check.

thelonegroover

Unless you know the BB has been faced, it's always worth doing. However, my question is: if you know the BB has been faced, say a couple of years ago. You then fit a new BB, would you need to face again?

nicklouse

no as it has been done.

unless it is all crapped up and corroded that is.

The Rookie

Facing at my LBS was just £7.50 (probably £10 without my frequant customer 'mates rates), cheap compared to trashing a BB, no brainer.

As an aside, when they did my Kraken it didn't actually need it, it was spot on, my daughters Dirty Jo on the other hand was miles out, we took over 1mm off one side to get 85% of it with machining marks, it would have killed a BB in probably 200 miles.

paulneenan76

Ok, so when the new frame (C456) was built up at Christmas it was either faced, or didnt need facing, so with that in mind, unless its utterly caked in crap, it shouldn't need facing again?

Paul

levolon

my c456 was perfect

screw bb in and if it sits nice and even all round it will be fine

if it dont then face it

Chunkers1980

You both seem a little confused on the point of facing. It is so the shell on the bb tube face's are completely parallel with each other. If you've done it and not painted it then it will remain as was.

levolon

Chunkers1980 wrote:

You both seem a little confused on the point of facing. It is so the shell on the bb tube face's are completely parallel with each other. If you've done it and not painted it then it will remain as was.

no confusion here bud

frame was paint free and i checked BB cups with a vernier caliper and got even reading all round .
they butted to the frame even too so all good .

good way to check there parallel , and a vernier caliper set is cheap http://www.ebay.co.uk/itm/6-150mm-Digit ... 3a75cb2e3e

nicklouse

lon 456 wrote:

Chunkers1980 wrote:

You both seem a little confused on the point of facing. It is so the shell on the bb tube face's are completely parallel with each other. If you've done it and not painted it then it will remain as was.

no confusion here bud

frame was paint free and i checked BB cups with a vernier caliper and got even reading all round .
they butted to the frame even too so all good .

good way to check there parallel , and a vernier caliper set is cheap http://www.ebay.co.uk/itm/6-150mm-Digit ... 3a75cb2e3e

what a load of crap facing has nothing to do with the faces being parallel, they could be parallel and still need facing.

first they need to be perpendicular to the BB axis. when they are both perpendicular then they will naturally be parallel to each other.

but being parallel is not the reason for facing.

Chunkers1980

Still not really. You know what a parallogram is? Using verniers on each outer side would mean moving down at 90 degrees to each other would mean the same distance, that doesn't mean it is correct. It is parallel through the centre of the tube and the thread which you need to be square, as in a theoretical rectangle

levolon

nicklouse wrote:

lon 456 wrote:

Chunkers1980 wrote:

You both seem a little confused on the point of facing. It is so the shell on the bb tube face's are completely parallel with each other. If you've done it and not painted it then it will remain as was.

no confusion here bud

frame was paint free and i checked BB cups with a vernier caliper and got even reading all round .
they butted to the frame even too so all good .

good way to check there parallel , and a vernier caliper set is cheap http://www.ebay.co.uk/itm/6-150mm-Digit ... 3a75cb2e3e

what a load of crap facing has nothing to do with the faces being parallel, they could be parallel and still need facing.

first they need to be perpendicular to the BB axis. when they are both perpendicular then they will naturally be parallel to each other.

but being parallel is not the reason for facing.

8mths and loads of miles and still perfect is fine by me ..
even bearing pressure is even however you say it .

im done here

The Rookie

Thank god....don't come back.....

Yours may be fine, but you didn't know and were just guessing....

nicklouse

for those that want to see how a BB shell is faced here you go
viewtopic.php?f=10004&t=12650967&start=60
one I did earlier
sorry one or two pics have dropped out and i have not got around to sorting them

nicklouse wrote:

the main time was spent finishing of a GT dirt bike rebuild.

the frame had been sand blasted and painted and the headset cups and fork fitted and came with a few bits to be fitted.





first job remove the tape from the threads.



then chase the threads.



remove the handle to allow the facing tool to be fitted.



Fit the facing cutter.



then face the BB faces.



Not fully done



Done



Other side



remove tool and clean.



more in a bit.