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Out yesterday and my Raceface turbine cranks came loose. I’ve never had a set of cranks ever come loose so wondering if i should worry or whether I probably cocked up the install:
running with a praxis BB as the face face ones use cheese for bearings and paper for seals and never had one last more than a month or two before siezing. Even without washing the bike.
Havent ridden the bike much since building it but from memory the preloader was right on the border of undone completely / threaded so shimmed the cranks a bit and with what i had at the time & I dont think i then needed the preload adjuster. Bike’s done just over 300mls since I built it and last used in May with no notable issues.
there’s no visible damage anywhere and i caught it just as it was coming undone so trailside tightened but ut wasnt torqued to spec so obviously came lose again before end of the ride.
Wondering why it came undone in the first place…..likely overshimmed the so the axle was effectively too short? (Cranks still span freely) or could there be something more sinister lurking?
I have trust issues so reluctant to run them until i have a better idea what could be going on!
Depends what interface system you have and what you mean by it coming loose. Do you mean the preload collar backed off and it could slide side to side, it do you mean the crank was loose in the axle?
Sorry - no, not the preloader. That was rock solid. It was the drive side crank coming loose and letting the cranks slide side to side + drive side crank wobble.
Definitely worth looking closely at the interface. If it was rocking then the interface might have been chewed up. My first every ISIS turbine was out of tolerance and I had to educate the importer about when it not meeting the shoulder was a problem so it is possible.
If it is bad, you could bond the axle into the drive side crank and then use the non drive side for future removal. The only difference is which bolt goes in which side
Hopefully the axle is okay as replacing it is a three figure job
Thanks for the advice. Hand’t thought about “swapping sides”.
Interface all looks ok now its cleaned up. Its Cinch rather than isis. Deffo no chewing up the ends of the axle as I caught it before it was at that point although tolerances who knows!
Thinking I probably overshimmed it to start with so the crank wasnt fully onto the axle. I’ve some lock tight from bonding the crap V1 ally Rise linkage so will remove a shim and if its still coming lose I’ll bond it and using the other side.
My experience of RF cranks is once they've come loose once they will never stay put properly again 🙁
Yeah, I should have twigged when you said preload, it has to be the modern 30mm axle. ISIS used a shoulder on the BBC for repeatable location and the square taper used optional spindle lengths for chainline. The ISIS story was just to highlight that sometimes the tolerance is out and when it is, you often have a struggle to convince someone that's the root cause.
My experience of RF cranks is once they’ve come loose once they will never stay put properly again 🙁
My Atlas ones came loose once mid-ride, tightened them up at a pub and they've not budged since. I did replace the tightening bolt though as the threads on that looked a bit worn.
Check everything for damage, torque it correctly and monitor. Both my RaceFace cranks have been solid.
Check everything for damage, torque it correctly and monitor.
i’m thinking this.
No visible damage. I recon i mucked up the install putting that extra shim in.
This has happened to me before, same cranks. I found that I just hadn't torqued them up enough, the recommended values are quite high (50Nm, if I recall). Since then I've been wanging them up as tight as I can, and they've been fine.
Sounds like you put too many shims in to me. I have these cranks and when refitting always wind the preload in so there is still some side to side slack after torquing the crank bolt up (yes to 50Nm) - then take slack up with preload collar.
I've adjusted to different BBs with spacers on the threaded BB - got some slim ones as well as the usual 2.5mm
In your situation I'd lightly grease the interface and bolt threads and torque to 10% over to be sure it's well seated and hope that fixes it.