I recently switched the cranks on my KH 24 and despite me greasing the splines before attaching the new cranks, I’m unable to tighten the crank bolts to the point where the cranks are fully pressed against the spacers. It is pretty darn close, but if you look closely you can still see a very small gap between the crank and the spacer on each side.
My main concern is if I run the risk of damaging the hub if I ride it like this? I weight 210 lbs and I’m afraid that I might bend the ends of the hub because the cranks aren’t utilizing the spacers.
Lastly, I had to really strain to get the bolts on as tight as they are right now so adding more force might strip the threads. Can I just switch to a slightly thicker spacer so I don’t run into this problem again?
Before inserting the threaded bolt you need to tap the crank on with a rubber mallet. You don’t mention what cranks you are using, but if the new cranks are not as thick as the old ones then you will want to put thicker spacers on.
I have never tapped my cranks on. Only ever threaded the bolt in and tightened real good. I’d get thicker spacers but that’s just me.
The spacers are there to prevent crank creep and hold the bearing in place. if they are almost touching that is probably good enough.
You aren’t going to bend your hub.
P.S. If you’re using a short allen wrench then you may not have enough leverage to fully tighten the bolts. You can lengthen your allen wrench with a piece of steel tubing. You don’t have to use a lot of force, just tighten the bolt firmly.
Please let us know how you get on.
Personally, I’d ride with a long 8mm allen wrench and check them a few times a ride for tightness. They may settle. If they don’t and then the spacers rattle, I’d get longer spacers. A 27.2 KH post cutoff section works well in a pinch. Cut with a pipe cutter.
Crank and hub tolerances vary, so you need a variety of spacer thicknesses if you are swapping cranks.
Barely touching is better than having the cranks go on to loose since the pressure between the cranks and spacers are not enough to keep the cranks from loosening.
The spacers are not to keep the cranks on the hub, they are to keep the bearings from “floating” off the spindle.