Bottle cage threaded

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robert17
Posts: 381
Joined: 24 Mar 2009, 1:41pm
Location: Worcs

Bottle cage threaded

Post by robert17 »

People, the used bike I recently purchased appears to have just one small issue. But, it is one I've never come across before. The bike has no bottle cages, yet the bolts were there. So I pulled two cages out of the spares box and got to work. One of the bolts was very stuff to remove the whole way and on replacing with cage that bolt just kept turning - threaded! Bugger! Alloy frame - any ideas? Thank you.
Eyebrox
Posts: 583
Joined: 5 Aug 2015, 8:56pm
Location: Ayrshire

Re: Bottle cage threaded

Post by Eyebrox »

robert17
Posts: 381
Joined: 24 Mar 2009, 1:41pm
Location: Worcs

Re: Bottle cage threaded

Post by robert17 »

Thanks for that. However the thread is stripped, so looks like a shop job. Thanks again.
David9694
Posts: 908
Joined: 10 Feb 2018, 8:42am

Re: Bottle cage threaded

Post by David9694 »

I haven’t viewed the You Tube, is it rivet-guy? He’s great - “I am gonna go ahead and...”

can you not recut the threads? Hopefully that’s what your Lbs will do - otherwise it’s likely to get disproportionally expensive. I don’t understand the science, but alu and steel can get very attached to each other left in close proximity over time with a bit of damp.

This might be kill or cure, but if no bite on the original size, you could try going up a thread size (to M5 IIRC) and re-cut?

You might need to do a little filing or drilling on the holes of you cage to ensure a thicker bolt will pass through.

Either way, try and clean out any gunge first and go gently on the threads with the die, apply oil to avoid shearing the boss. Go cautiously eg a quarter turn in and one eight back

If you’re like me, not from an engineering background, dealing with threads is commonplace in that world and the cutting dies you need are cheap to buy.

The DMR clamps are a reasonable alternative to integrated bosses if all else fails.

Have a look here to see what it is you’re dealing with:
https://www.framebuilding.com/Bosses.htm
Spa Audax Ti Ultegra; Genesis Equilibrium 853; Raleigh Record Ace 1983; “Raleigh Competition”, “Raleigh Gran Sport 1982”; “Allegro Special”, Bob Jackson tourer, Ridley alu step-through with Swytch front wheel; gravel bike from an MB Dronfield 531 frame.
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robgul
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Joined: 8 Jan 2007, 8:40pm
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Re: Bottle cage threaded

Post by robgul »

robert17 wrote:Thanks for that. However the thread is stripped, so looks like a shop job. Thanks again.


Assuming it is a rivnut (as the film) then it's a dead easy job to drill out and refit a new rivnut - shouldn't take more than 15 minutes

It's a fairly common problem - I've fixed a couple at my shop in the last few months. The rivnut is also a simple add-on for frames without bottle bosses

Rob
E2E http://www.cycle-endtoend.org.uk
HoECC http://www.heartofenglandcyclingclub.org.uk
Cytech accredited mechanic . . . and woodworker
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