Should it be this tight?

CombiD

I've got a (2006 i think) Commencal Meta 4.3 frame that i've been building up. Had it powder coated etc. anyway, to cut a long story short i've got a Truvativ Firex crank and GXP XR bottom bracket (both 2nd hand - i'm poor). When i've tried to screw the BB cups into the frame it only goes in for about 3/4 of a turn before it is very tight and won't turn by hand. Should I get the bear out and give it some or is it meant to be installed by hand and then the final torque settings achieved with a tool?
The BB shell has been re-faced by LBS and there is no overspray from the powder coating in the threads.
Any help would be much appreciated. Thanks.

Chunkers1980

As long as you're sure you're cross threading it by hand as far as you can get it, a little bit only by tool is fine to biting point. Then torque as the manual

CombiD

Thanks for your reply. Problem is that most of the thread is still showing when it gets tight.

Chunkers1980

Are you sure frame and bb threads are all good?

thistle_

If it's been powder coated have the threads in the BB shell got coated by accident?

The Rookie

+1 where the threads masked off when it got coated? If not I think it's LBS time to get them to cut the coating out the threads!

CombiD

There doesn't appear to be any coating in the threads but at least I know now that it's not meant to be tight. Thanks for all help.

nicklouse

get the frame threads chased out and get the BB faces Faced.

ThePriory1978

Out of interest.

Am i right in thinking.
A bikes BB can only be chased once? If the threads get screwed a second time the frames scrap?
A BB shell can be faced more than once but is not advisable.

So how does Carbon Fibre work?

nicklouse

ThePriory1978 wrote:

Out of interest.

Am i right in thinking.
A bikes BB can only be chased once? If the threads get screwed a second time the frames scrap?
A BB shell can be faced more than once but is not advisable.

So how does Carbon Fibre work?

the threads can be chased as often as needed. faceing only needs doing once unless there is a need EG paint or poweder coat. doing to much could take the shell width out of tollerance.

So the other way arround to your thoughts.

YeehaaMcgee

ThePriory1978 wrote:

Out of interest.

Am i right in thinking.
A bikes BB can only be chased once? If the threads get screwed a second time the frames scrap?
A BB shell can be faced more than once but is not advisable.

So how does Carbon Fibre work?

As Nick says. Chasing a thread is basically jst cleaning it out. It doesn't neccesarilly remove any material.

What the hell does any of that have to do with carbon though?

bennett_346

Am i right in thinking the threads for BB on carbon frames are metal inserts? I'd find it hard to believe they'd be carbon threads.

Chunkers1980

Yep.

DodgeT

Yeah, alloy inserts.
Also, saw them in LBS fixing a knackered bb thread, 2 options were italian thread, apparently there's just enough material to allow the new thread to be cut. When really bolloxed, they could clean out and fit/bond a new insert.
I also know someone (not me) who bonded a bb into a completely farked frame and it worked fine. Just have to hope the bearings last...

ThePriory1978

bennett_346 wrote:

Am i right in thinking the threads for BB on carbon frames are metal inserts? I'd find it hard to believe they'd be carbon threads.

Chunkers1980 wrote:

Yep.

I didnt know this. Now i do.