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Lefty Axle thread - Helicoil

7 posts & 3 voices | Started 10 months ago by fyford | Latest reply from fyford

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fyford - Member

Advice on fitting a HeliCoil

Chaps, I'm pretty sure experiences will be thin on the ground, but I will try nevertheless... my Cannondale Lefty spat out its helicoil - I've found a forum suggesting to get a m10-1.0 replacement coil. I did this, bought 10 in fact. They go in smooth, but the moment I try to fit the wheel back the nut seems to really struggle and if I remove the wheel the coil starts to come out with it.

So if anybody has some experience with this please let me know how I can fix this. I've wasted 5x of my replacements thusfar......

Posted 10 months ago #
TandemJeremy - Member

Forgive me if I am teaching you to suck eggs - I take it you ran the correct tap thru first? You need to cut the correct threadform to accept the inset - and have the correct tool to fit the insert.

http://www.helicoil.com.sg/HeliCoil-Installation-Instructions.htm

Edit - sorry - was it already helicoiled? any pics?

Posted 10 months ago #
MidlandTrailquestsGraham - Member

What do you mean the nut starts to struggle ? I'm not familiar with Lefty forks.
Nuts have got a female thread, helicoils take a male thread (bolt).

Try threadlocking the helicoil in.

Posted 10 months ago #
fyford - Member

Hi guys, Jeremy it was tapped with a helicoil, I understand this is how it comes from the factory. I don't have any helicoil tools, just hand screwed it in. Where the bolt fitted in the previous one without me even realising it is screwing into a helicoiled axle it now seems really stiff (struggle - won't go all the way in) and I've been reluctant to force it all the way in. I understand you can get different pitches... not sure if this is my problem. Graham, thanks for the tip on threadlocking - only just found out about that. Will try to get some, blo0dy Halfords want £7 for a tiny tube, but that's the only place I can find some.

Been speaking to the guys at Noah's ark in Stroud, said I should phone again tomorrow. Will post my findings on here for the next sod who finds himself in this position. Hopefully I get to sort it out before the Bontrager 2412!

Thanks for the

Posted 10 months ago #
TandemJeremy - Member

something is wrong with the fitment of it all. You should not need to threadlock a helicoil in and it should just screw in as easily as a standard thread. Tehre are different makes of thread insert so perhaps therea re incompatibilities there

Posted 10 months ago #
fyford - Member

Not too sure what the deal is, as I said the helicoil screws in really easily into the axle thread - just the bolt won't go into the helicoiled hole...I finally got hold of the UK Lefty expert, Carl, at Noah's Ark. He said the Lefty helicoil is specific to Cannondale, so I guess this has something to do with the pitch...? Don't see another way as to pop in there on Friday for them to fit it. Quoted me at around £40... seems excessive for what is such a small part. I'm tempted to take the camera along and take some snaps of him doing it to help out the next guy. Will ask for some spare helicoils too as I don't want to be caught out like this again! Apparently this is a known issue - supposedly caused by overtightening the wheelbolt. Can't say I've been giving it a lot of muscle, but then again maybe the psycological effect of 'Lefty concept' made me tighten it more than usual - who knows. Will slap an update here when fixed.

Posted 10 months ago #
fyford - Member

Ok so I've had a 'Cannondale' specific helicoil fitted by Carl at Noah's Ark in Stroud. It turned out the thread on the bolt in the end cap was worn so I got a new bolt as well. Carl simply screwed in the helicoil - NO THREADLOCK and it seems ok thus far. I was quite pleased to hear that in the case of the the axle thread getting ruined you can simply get a new end piece for the Lefty. I was imagining it would be a Lefty in the bin scenario! So there you go, hope this helps the next guy. I am still not 100% convinced that Cannondale have a completely unique helicoil-pitch, but Carl said he's not found any alternative which worked... my M10-1.0 certainly did not and was told that was probably what knackered my bolt so be warned! It screws in easily enough just to give you that false sense of security!

Posted 10 months ago #

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