Discovered some 'play' in the crank arms while riding and realised that the drive side BB shell had worked itself loose while riding. 🙁
On returning home I've tried re-fitting the drive side BB shell, but it just 'slides' in and out, only slightly holding, maybe for the last few threads.
I tried re-fitting another new BB shell and this is much better - yay 😀 ! I can get it up good and tight, no worries, but compared with the non-drive side there is a slightly noticeable 'wobble' on tightening, however, this disappears once the shell is done up tight.
[b]I've read about getting BB thread 'chased' at my LBS - will this help?[/b] Or is this just for cleaning grotty threads?
Surely it can't be possible to 'magic' thread material (from nothing) by this means?
Any other ideas?
Lots of loctite?
Get a decent lbs to helicoil it.
It has to be worth getting your shop to run a chase through it, although the fact that the cup slides in doesn't bode well.
Somewhere like Betd will probably be able to save the frame with a threaded insert - for around £100, if I remember correctly. What make of BB is it? Some cups use longer threaded portions (Saint and RaceFace, perhaps). I can still see them working loose over time, but it's got to be worth a try.
[url= http://www.tritoncycles.co.uk/products.php?plid=m13b199s110p3339 ]Go square taper with this £15 option?[/url]
Arrrghh.. no, square taper is not an option! 🙂
I'm saving the whole 'threaded insert' option as a last resort. It's a pain in the ass to have to send the frame away TBH and I've only just got it back from a re-spray 🙄
Given that a new BB shell with undamaged threads seems to go on tight ok, I'm hoping I'll be able to use a shed-load of loctite and that'll hold it for a bit, and maybe having the threads re-tapped / 'chased' beforehand might give it a fighting chance also?
You could also try a deeper BB, IIRC Saint has a deeper driveside thread.
PS don't use a shedload of loctite, a little might be a good idea but a lot will just make it a bollocks to get the BB back out, which might end up damaging the thread even worse. Personally I'd get it chased, by a mechanic you really trust, though it might not actually make any difference.
Those yst brackets are not very good and come undone even if loctite is used
Personally I wouldn't go down the loctite solution, get a decent LBS to retap it (£10 approx.). Gut feeling is that what you describe is beyond a retap, so helicoil might be the solution, investigate a retap first tho.
It's only an idea, but beyond that, maybe investigate an alteration to press fit BB, I don't know if this is possible.
I'm in a similar situation, bought a 2nd hand frame and one of the BB threads had obviously been cross threaded by some ham fisted idiot. Luckily, it was just very tight to screw in by hand, I think it will be re-tapable when the bb needs replacing.
Try a Saint bb or a Raceface fr/dh deep fit BB