[Closed] Boring but useful (to me) thread: Why does my crank keep coming loose?

Square taper or isis etc?

where is the wobble?

NDS crank wobbling on the axel?
or the whole crank assembly wobbling in the bottom bracket?

I tried a crankset in a hope BB and it developed a wobble, as the race surface was a TINY amount smaller than the hope bearing internal Diameter.

changed the Crankset for a new one in the end.

I had this happen. The bolt was tight but there was still a teeny bit of play.

I ground a couple of mm off the end of the axle, because in taking the crank on and off a few times it had bedded a little further down the axle and the splines were protruding past those of the crank.

It now works fine again.

Edit - X-type BB

or if it is Sq taper then i could be the wrong sized/shaped BB?
or rounded taper on the cranks?

I don't know the answer, but when my Truvativ's took to dropping off I went after them with No More Nails. They have not moved since, and will next move when I apply a hacksaw. I appreciate this is not something you necessarily want to do with a pair of £200 cranks....

After tightening them up double bar5tard hard

that may have some relevance!!

No, those cranks really do have to be tightened doubleard.

RaceFace say the drive side crank is to be tightened double bar5tard hard onto the axle, that it is not possible to over-tighten it and that it is a "hard stop". All of which is still terrifying when you're swinging on the end of a massive allen key and it's still turning (just). I fitted some 2 weeks ago, and am now trying to take them off again. I'm not convinced it's a terribly good design... 🙂

I've got an set of RF Evolves from roughly the same era - they have a little spacer on the spindle on the chainring-side of the crank. Not sure if they have same setup as RF Deus, but if so, you may have inadvertently lost this little spacer when removing the cranks from old bike - hence the looseness? I forgot to put this little spacer on once and my cranks were quite loose after a little test ride.

The splines do wear out on RF cranks. (don't they Rob?!)

BD, your adapter has just been posted. 🙂

You're a star Dez, thanks. 🙂

Wow, sorry for not answering the questions, I've been trying to do some work (heaven forbid!!).

It's just the DS crank arm coming loose (ie the bolt coming undone).

I think Harry PB has the answer, as I had a suspicion there might be spacer missing. I only have the red ring which sits against (sort of inside) the crank. should there be another one? If so, where can I get one?

Thanks for all the help.

I might have one (if it didn't get damaged in the act of sawing the crank off!) Will have a look tonight.

If the whole thing (both cranks) can move from side to side it's a spacer.

If just the drive side crank waggles a bit (and you can feel the flex through the pedal) it's what I said.

DezB, if you do have one I'd really appreciate it. Thanks for looking.

when i read the thread title, i found myself asking 'race face?'

that's probably your answer.

sorry, they do have a reputation for this...

Tell me about it.

Take off the drive side crank arm. Wipe the grit and grease away from the splines and have a good look at them. You will most likely see some ovaling or 'scalloping out' at the end of a few of the splines. It wont be much, just a mm or so. No amount of torque will stop the dreaded wobble for long. It might feel Ok in the garage, but after a few miles it will work loose.

I have made a decent set by mixing a Deus and Evolve ( unmatching cranks .- Don't tell the bike police )

BB - ygm

Just to make an official announcement:

DezB is tops...!

😀

While you've got the thing in bits, just remember to grind a couple of mil off the end of the axle.

BigJ: Will do if the spacer doesn't sort it.

Thanks for all the help.