Author Topic: Problem with new hub? Any ideas?  (Read 194 times)

Problem with new hub? Any ideas?
« on: May 23, 2020, 07:04:31 am »
I’ve just built up a new pair of wheels using Novatec D791/792 through axle hubs.

When off the bike the freehub, with the cassette mounted, spins freely. However, when I tighten up the through axle the freehub starts to drag and spinning the wheel spins the chain set. If I hold the chain set then there is a reasonable drag load, which is dependent on through axle tension.

I’ve pulled the axle out and free hub off and there is nothing obviously wrong. Clearly it relates to axle compression, but what could be binding? Ideas gratefully received!!




Re: Problem with new hub? Any ideas?
« Reply #1 on: May 23, 2020, 08:32:32 am »
Some washer not installed properly?
There is a washer covering the freehub and there is another one between the freehub and the flange... they both can bind if they are installed inappropriately

Re: Problem with new hub? Any ideas?
« Reply #2 on: May 23, 2020, 12:57:24 pm »

I remembered that I had another wheel sitting in the shed with a (superstar branded) novatec hub that uses the same axle and freehub. So I pulled them both apart and there are no obvious differences (I didn’t take the vernier to them) except the spacer that sits at the hub she’ll end of the freehub on the axle sits slightly proud on the superstar copy. I suspect that the spacer is slightly short and when the axle is compressed by the dropouts it was forcing the end of the freehub to bind on the hub bearing or shell itself. Not much, but enough to be unhelpful.

I swapped the old axle and freehub assembly to the new hub and everything works perfectly. I haven’t tried the older wheel yet, but suspect it may need either some hammering adjustment or a new freehub and spacer to work properly

Interestingly, the NDS end cap on the faulty assembly was less tight than that on the good, and I had considered that leaving the cap slightly loose would allow space for compression if needs be. However, nice to be able to ride the bike and to freewheel without fear of the wheel falling off.

Of course, the old wheel is now in the projects list...