helicoid inserts...where/who

[tenbikes]

I have need of a pair of crank arms that have a low Q factor. I do not require a chainring on the RH one.

Square taper. 165mm

Won't be able to just buy that requirement, so how about x2 LH cranks arms and switch one of the pedal threads to RH using a helicoid insert?

? Where / who would do this work? I have a pillar drill and some skills. DIY job?

[tatanab]

Bare RH crank https://www.spacycles.co.uk/m8b0s109p39 ... Hand-Crank
Bare LH crank https://www.spacycles.co.uk/m8b0s109p39 ... Hand-Crank

[tenbikes]

I saw those, but it doesn't say what they are made of. Looking for something a little smart too: bike has cost 5k to build !

I have Middleburn SR7 fitted just now but the Q factor is massive....

[fastpedaller]

The holdsworth track cranks from Planetx have a low Q
ETA it looks like they only have the road (longer) ones in stock - maybe worth a call?

[Jdsk]

? Where / who would do this work? I have a pillar drill and some skills. DIY job?

I don't know the factor you'd need to reverse a thread. Is it only the same as drilling out a correct thread of the same size and starting from there?

Fitting a Helicoil (or similar) isn't difficult. Drilling the hole true can be.

I'd probably ask some bike pedal rethreader specialists as a first step.

Previous discussions:
viewtopic.php?f=5&t=129338
viewtopic.php?f=5&t=136231

Jonathan

[fastpedaller]

Just a thought - it would need someone who could make up a special bush, as putting a RH thread helicoil into a LH thread crank (or vice-versa) wouldn't work,

[KTHSullivan]

Helicoil inserts are generally only any good on blind holes; when one inserts the spring like replacement thread one normally breaks off the insertion tang with the insertion tool. Obviously if the hole is not blind as it is in a cycle crank it will simply wind through the hole. A better option would be to remove the thread completely and then insert a male/female threaded bush, the internal thread to match that of the proposed pedal.

[KTHSullivan]

Just a thought - it would need someone who could make up a special bush, as putting a RH thread helicoil into a LH thread crank (or vice-versa) wouldn't work,

Beat me to it

[tatanab]

I saw those, but it doesn't say what they are made of.

Forged 2014 alloy crank arms (2014 is stronger than 6061 and 7005) with a polished silver or black anodised finish. https://www.spacycles.co.uk/m8b0s109p30 ... ing-Cranks

[tatanab]

? Where / who would do this work?

https://highpath.co.uk/crank-repairs-and-modifications/

[tenbikes]

Brilliant guys, just brilliant. I knew asking here was the right thing to do )