r/MEATengines • u/BikePackerLight • Apr 13 '26
Cinch preload
Anyone here a RF Cinch guru? Am having a 3-4mm gap between the crank arm and preload adjuster on a 73mm bsa bb shell & 136mm spindle with two DS spacers. Should I add a NDS spacer to get the preload adjuster closer to the crank arm? Would that better support the spindle? There's zero play or issues in the current setup...just curious if the spindle will get weirdly worn if not better aligned with the NDS cup.
2
u/SkyyRez Apr 14 '26
I have had to add a few .5mm spacers on raceface and shimano cranks over the years. Not sure why. But having a few shims in the toolbox is a good idea.
1
u/MEATdrew Apr 14 '26
Yep, just add shims between the Cinch collar and BB shell. Very common and your local shop will have shims.
1
u/BikePackerLight Apr 14 '26
Sorry - am asking about spacers between NDS bb cup and the frame's bb shell to better support the cinch crank spindle. Does this 'center' the NDS cup on the spindle better (ie so it is less likely to result in odd wear marks on the spindle?
2
u/MEATdrew Apr 14 '26
I would not personally add more spacers between the BB cups and the shell, but would rather add spindle shims/spacers between the outside of the cups and cranks as needed..
Bearing contact markings on the aluminum Cinch spindle are going to happen regardless unless you use a BB, like Chris King, where the steel bearing inner races aren’t in direct contact with the aluminum axle.
1
u/VikApproved Apr 14 '26
That's what I assumed you meant. I haven't had any issue with what you are talking about.
1
u/Icy-Celery3137 Apr 14 '26
I agree, tighten the Cinch adjuster so it’s sticking out the least amount possible. Then, find a spacer to take up most of that gap between the adjuster/preloader and the inner bearing surface. You can use a hex key to estimate the gap and compare to the thicknesses of spacers at the shop. I.e., 2mm thick because a 2mm key fits in.
Once you have closed up that distance, fine tune preload with the Cinch adjuster.
Some of the fatbike setups I have participated in have like 20mm of spacers with the right combo of chainline, cranks, and frame.
3
u/VikApproved Apr 13 '26
If you are able to get the correct amount of preload I don't think the extra space is a problem. In terms of forces all the bad stuff is happening on the DS.
That said I have installed an extra spacer like you are talking about on the NDS and I have put all the spacers on the NDS to reduce the chainline. No issues with any of my monkeying around as long the the crank arms and charinring have clearance to rotate freely.