Threaded thumbie - solution?

[ededwards]

I think this has been asked before but I can't find the response.

I've an excellent condition thumbie with a threaded clamp (not badly but it doesn't quite tighten up enough), is there any way of solving the problem?

Cheers

Ed

 

[JustKev]

I'd drill it through and use a longer bolt and a locknut.

Be fine for a rider unless its your best showbike Ed?

 

[utahdog2003]

If you mean it has stripped threads, then clean it out and tap it one size larger. Then either run a Heli-coil or just use a larger cap screw in your newly threaded hole. Good as new!

 

[JeRkY]

as above.

 

[ededwards]

Excellent and rather as I figured - let the power tools loose!

 

[Carsten]

first try if a longer bolt works. the original bolts usually dont fill the entire threaded hole and thus sometimes a few intact threads remain at the end. if you tighten the longer bolt carefully it may still work.

carsten

 

[DM]

^^ What Carsten said.
Assuming you mean XT thumbies: The thread in the cast alu clamp is longer than the original bolts, so there may be some good thread left in there.

The steel clamp & nut/ bolt arrangement of the Deore thumbies is a bit more reliable... they just don't LOOK as good. :roll:

 

[utahdog2003]

Don't forget also that these things don't need to be super tight. Same for brake levers. Snug them up just past the point of moving on the bar and then you'll never have the problem again. (unless you inherit the problem from recently aquired used stuff, that is) Plus, if you fly over the bars, ass over teacup, you'll not break anything off like a lever, you'll just spin something on the bar.

 

[ededwards]

Top additional thoughts - I had wondered about a longer bolt but as the bolts in question are red ano this may already have been done.

The thumbie is almost tight enough to use but in reality moves on the bar without much pressure so just needs to be snugged up a tiny bit but won't. I can use it as it is but it makes changing gear a bit more of a studied exercise and I worry that changing gear then realigning the thumbie many times will ultimately score the bar.

So, explore longer bolt first, get drill out if unsuccessful.

Thanks guys

 

[pistol13]

I've just repaired mine. The threads were to far gone for a longer bolt so filled the hole with jb weld. Let it set for a few days. Drilled with a 4mm bit and then used an m5 tap. Now sorted and as good as new