Thread gone on frame

Keen and mean

Any ideas what to do, iv just bought a new fsa BB with a new crank as my old bb was just spinning and came loose, the trouble is now the thread has been worn way from the frame due to wear and the new bb has nothing to tighten up to¬
So kinda stuck now as to what to do hence the message here :?

wishitwasallflat

Someone will be along to correct me if I am wrong pretty soon but I am sure you now need to get the frame rethreaded - called chased and faced - which your lbs should be able to do for you as you need specialist tools.

styxd

called chased and faced

Arent they a drum and bass duo?

Take your bike to a shop. They may be able to retap the threads in the BB shell if theres enough material left in there.

If not, theres a chance your frame is fucked. A good frame builder or Argos cycles or BETD may be able to fix it for you.

Also, BB threads dont just "wear away" you/someone hasnt fitted the BB correctly the first time.

g00se

What sort of BB are you using?

There are some threadless BBs available for old square taper types.

Salsa

g00se wrote:

What sort of BB are you using?

There are some threadless BBs available for old square taper types.

Yeah like these >
http://www.ison-distribution.com/englis ... t=BBIDT810

Keen and mean

Iv got a giant scr 1.0 frame with english thread would this fit
http://www.tritoncycles.co.uk/m13b0s110 ... atridge_BB

g00se

I would think so. For a standard English thread, you'll need a 68mm.

Next, the actual size of the BB needed will depend on the type of square taper cranks you intend to use (you can't get them for external/hollowtech/ultratorque BBs) and the width of the bottom bracket frame shell.

Finally, the actual taper of the spindle differs on manufacturer. Shimano etc will need JIS tapers, Campag will need ISO tapers (not sure about other brands).

Keen and mean

Ok iv just bought on of these from ebay and it comes with a bb fsa 19mm and everything fits but as the thread is gone im stumpped!!!!

http://www.chainreactioncycles.com/Mode ... elID=35734
will the threadless bb fit the cranks as one end is threaded into the crank itself its not a square crank

g00se

The threadless BBs won't work with a MegaExo chainset. Sorry. Time for a trip to the LBS to see if they can fix the thread...

Keen and mean

But the thread is gone if they retap it surley the bb will not tighten up as the thread would now be bigger??

g00se

It might just need clearing out (fingers crossed) or I suppose they could cut it as an Italian thread.

I've read about reaming the BB wider and fitting an insert to bring it back to the right size - but I don't know is this an expensive frame builder trick or something a decent LBS can do?

Keen and mean

How about throwing in some metal glue and clamping it till its hardens he he

andrew_s

Retapping the threads ("chase and face") is only any good for clearing paint out of the threads or for fixing the threads after you've cross-threaded them. As you say, it's no good if the metal isn't there.

If the threads are worn - i.e. make like to tighten up, but then go loose again, then the options are...
a) a square taper threadless BB, with new cranks if you are using something different
b) Araldite or whatever. This leads to the question of what to do when the stuck in BB fails.
c) Give it to a framebuilder. With a steel frame there are various methods - build up the inside of the shell with braze and tap that; reduce the BB shell size by putting a cut through it, squeezing the cut shut and welding/brazing it up; ream out the old threads and braze in an internal sleeve. For aluminium frames, I've no idea. Argos in Bristol charge £75 for ream and sleeve, plus you'll probably want a respray afterwards.

I'd pay up for ream & sleeve on a good steel frame, otherwise I'd use a threadless BB and get a new chainset to match. You can eBay the non-square chainset.