Freehubs - different lengths?

[Watchman]

I have built my family three separate bikes based upon the Planet X London Road frame & forks, and a load of other components I've sourced as the opportunity arose.

At some point I bought a set of 700c disc brake wheels for one of them (as I did for the others) but upon trying to finish the bike today I've not been able to tighten the cassette onto the freehub. The cassette in question is an 8-speed Shimano.

I disassembled one of the other bikes, a 9-speed, to see if that 9-speed cassette would fit onto this troublesome freehub. I know a 9-speed is only as wide as an 8-speed in theory but I thought I'd check. It didn't. It too was too loose once the retaining screw was tightened.

Incidentally, the 8-speed cassette fits perfectly onto the freehub from the 9-speed bike.

I measured the length of the two freehubs and the troublesome one is about 4mm longer. Is this a "Chinese" manufacturing fault or are there different length hubs? I have a 10-speed bike too but I've not tried taking that apart yet to compare - thought you chaps might know the answer instead.

[Watchman]

Sorry for talking to myself... but I found some indication that 7-speed freehubs are 31mm, then 8-, 9-, and 10-speed freehubs should be 35mm, although I'm not sure where they are measuring this from. I'm sure mine are all longer than this from where the freehub meets the wheel hub.

[anonymous-user]

So the cassette is too short?

Have you missed a spacer out?

[Watchman]

The cassette is too short, yes. But it's the right length on the other freehub. There are no spacers required with the other one, and I don't have any anyway.

The length of the splines are exactly 35mm (this is the "bad" freehub).



When the cassette is seated in place, there's a gap between the smallest two sprockets. The smallest sprocket cannot move down any further.

[CoolC]

That looks like an 11 speed freehub. There should be a spacer behind the cassette.

[Mazinbrum]

https://www.sheldonbrown.com/cribsheet-spacing.htm...

[Watchman]

CoolC said:

That looks like an 11 speed freehub. There should be a spacer behind the cassette.

Yeah, I think you're right.

Here we go... found this:



Mine is just shy of 37mm measured from the back of the splines (where the diagram shows above) to the end of the body, so yep, it's an 11-speed.

The other one is just shy of 35mm, so definitely an 8-, 9-, 10-speed.

Damn.

Thanks for your help.

[Mazinbrum]

Easy fix then
https://www.wiggle.co.uk/lifeline-rear-hub-cassett...

[Watchman]

I have a damaged spare wheel with a 35mm freehub. All I need now is a 12mm allen key to swap them over. I'm horrified that I don't already have one (I'm a tad zealous about having all the tools I'll ever need) but Halfords seems to and they're open on Sundays.

Thanks again for all the advice.