- Apr 22, 2020
I'm thinking you are wasting your time in the message box and should be writing a dystopian science fiction novel.The surface is hard all right, but the base material still has the modulus of aluminum. The designer of the clutch overcame the problem of dissimilar materials by enlarging the pressure area acting on the aluminum. In their design, only a small fraction of the pressure load acts on the spline ends. Essentially, the small washer is there to ensure the large washer stays flat. It's a bit complicated to explain - load distribution is a product of area and modulus of the backing material.
In your loading scheme, virtually all pretension load and running load will transfer via the nut and small spacer into the splined ends, and there is very little pressure on the hub pushing its splines towards the tapered end of splines, which is the real design intent.
I fear you will see abnormal wear and clutch drum "wobbliness" before long. I guess you will just have to monitor the clutch assembly as miles stack up.
On the plus side of this experiment, nothing gets modified to the point that going back to the AMC clutch can't be done easily.
Given how little I actually ride the P11, I doubt I'll have any issues with the NEB clutch other than banging the gears some without any cush rubber in the clutch center hub or my rear wheel hub. Shifting into first from neutral might be a bit crunchy.
By the way, I think the AMC clutch also fastens with the nut pretension load on the shouldered end of the spined shaft. I'll be checking on that soon. If it actually tightened up on the taper spline cut, I would need a clutch puller to get the AMC clutch off. However, the clutch slides on and off after the nut is removed. The main difference is the little spacer is not part of the NEB hub like it is on the AMC clutch. It actually free floats in there. So I suppose it is possible that things could loosen up and trash the alloy splines if not torqued down tight. I'm not going to worry about it.