Wow, when race face cinch cranks go wrong, they really go wrong.
I was just thinking the other day how much I like the solution compared to HTII or suchlike. The direct mount chainring is awesome (and easy), love the simplicity of tightening the bolt on the drive side, then finger tightening the bearing pre-load on the NDS. Great system.
However - last couple of rides noticed a horrendous creak, and on getting home realised that the drive side bolt was working loose and the crank was v wobbly - oops! Read a bit about the 50nm pressure needed, I've no torque wrench that goes up that high, so now seated 'good and proper'.
This mornings big ride up a big hill with a loooovely extended single track descent was somewhat buggered by the continuing horrendous creaking being the NDS crank also working loose. noticed about 1/2 way down as that side was this time feeling 'wobbly'. Does anyone carry a 15mm Allen key needed to reattach it on a. regular ride?
I got the bolt 'finger tight', rode gingerly down, then dropped into decathlon at the bottom of the hill (nearest bike shop, second option was a car repair place) to see if they had a 15mm Allen key (I don't even have one in the tool box at home) and maybe even a torque wrench.
They had both, were super helpful, no charge, and things are creak free and reattached again.
Learns?
1) 50nm is an incredible amount of force, I've never down anything that tight before!
2) I need a 15mm Allen key
3) Once things start to go wrong, one really should check all the elements of potential knock on failure
4) I should have done that drive side bolt up correctly in the first place
Hope the cranks aren't buggered, heading for PPdS and a week in the alps next Thursday. the would be bad timing.
Has it stayed tight? I wouldn't have thought the tightness alone would be a factor on it working loose*?
*I have no idea. My Race Face Cinch Cranks are definitely not at 50nm, and they've been fine....
Check the pre load ring for cracks.
No idea how but mrsbeanz is on her 3rd pre load thingy.
My experience with anything on a splined connection is once they've come loose once they'll do it repeatedly until replaced, regardless of how much loctite etc you use on the bolts.
I bought a 15mm allen key on eBay recently (to remove a Shimano freehub though) it came stamped as made in W. Germany which was a surprise considering it was new, but it works well and was much cheaper than Park one. I recon you'll be most likely be fine now though.
These things can work loose, hopefully you've got it sorted now.
How did oyu fit it in the first place if you didnt' have the 15mm out of curiousity?
The clue to the torque is that it's a huge fitting - the shimano/campag/SRAM 8mm allen key ones are generally 35-50Nm kind of range, so that's definitely towards the "just nip it up gently" end of tightness for a bolt with that head on it.
50nm is an incredible amount of force, I’ve never down anything that tight before!
Cassette lock ring? Hope one is 70Nm, Shimano is 40+
Check the pre load ring for cracks.
Good call, have done, its OK - must be easy to break its a flimsy piece of plastic
once they’ve come loose once they’ll do it repeatedly until replaced
yeah, I'm not holding out a lot of hope, but keeping my fingers crossed. this chainset was really the only thing I couldn't transfer across from the old bike, and it was expensive!
How did oyu fit it in the first place if you didnt’ have the 15mm out of curiousity?
in the box, the crank arm for the NDS was already fitted on the spindle, I assumed it was fine (RTFM!)
Cassette lock ring? Hope one is 70Nm, Shimano is 40+
Fair enough, I never do up my Shimano cassettes that tight though - never had any issues, except one time when I had to remove one fitted by my LBS that must have been waaaaaay over 40!
Also, just had a look at the installation instructions that came with my cranks - it mentions nothing about the NDS crank, where the instructions on the race face sight do (and reference a 8mm - 16mm adapter (note was 16mm I used today) which was not in the box).
Hmmm, annoying.