I have a set of RF Ride fat bike cranks on my Puffin.

The original BB died recently and I’m about to refit a replacement.

The pre load facility of the cranks is really basic e.g. a single bolt that pre loads and also holds the DS arm on.

The original BB I suspect may have suffered premature failure due to being “over pre loaded”.

To avoid this happening again how is best to get the cranks tight enough to remove play without over tightening them?

I wish Shimano did fat bike cranks 😆

I thought there were washers with RF cranks to do the pre-loading?

So you always do the external bolt up ‘bastard tight’.

http://www.raceface.com/instructions/CRANKS/Ride_XC_Crank.pdf

It might just work TBH – Ive run loads of shimano BB / RF combos and the shimano BB has lasted as well as it should, however if you do want to fettle you have 2 options:

1) Behind the red rubber preloader there will be probably 2 black spacers – you can remove 1 of these to make the cranks effectively wider, reducing the pre-load.

2) Face your BB back to 73mm – it may be too wide.

You need to crank the bolt until it stops, don’t try to adjust the pre-load by running the bolt a bit loose – your cranks will fall off.

Hmmm.

I don’t remember seeing the 1mm washers when I originally fitted the crank over a year ago 😕

Edit: The Instructions I have don’t actually mention the washers.

Its 100mm BB 😉 But take your point to check its not over.

Think the washers/black rubber bits are pressed onto the crank arsm when they’re delivered.

If you got a year’s use out of the BB I say you’d done well, not damaged it with preload!

The main thing is to get your bb width accurately measured – IIRC it needs to be 68/73/83/100/whatever +/- .25mm which is fairly tight.

Beyond that, as suggested, spacers to get it just right or, as I’ve done with a bodged one that had the splines go and as a consequence is narrower than it should be, use a 24mm ID wave washer to take up any slack.

This sort of thing:
http://wheelsmfg.com/bottom-bracket-wave-washer.html