Rear hub, stupid numpty question

naffa
naffa Posts: 126
edited January 2012 in MTB workshop & tech
It may have been asked before but a quick search didn't turn up anything so I've gotta ask.

On the rear hub theres the bit where the cassette fits on, (is it called a freewheel)? is this a standard size or does the hub get wider the more rear gears the bike has?

I've got a 7 speed cassette and I know (thanks to your previous help) that if I buy a wheel/hub designed for 8/9 speeds I can use a spacer so my my cassette will fit on the hub, but if the hub is physically wider to accomodate the extra gearing I'm worried that the setup physically wont fit on my bike.

Thanks Nathan
Cheers Nathan.

Comments

  • supersonic
    supersonic Posts: 82,708
    The bit is called a freehub body, freewheels are built into screw on cog clusters.

    8/9/10 freehub bodies are the same size - to fit a 7 speed cassette you need a 4.5mm spacer.
  • naffa
    naffa Posts: 126
    supersonic wrote:
    The bit is called a freehub body, freewheels are built into screw on cog clusters.

    8/9/10 freehub bodies are the same size - to fit a 7 speed cassette you need a 4.5mm spacer.


    Thanks, so the hub in total is 4.5mm wider?

    Does anyone know the distance needed between the rear dropouts when using an 8/9/10 speed hub?

    Sorry for all the questions but as you appreciate its something I need to get right first time.
    Cheers Nathan.
  • supersonic
    supersonic Posts: 82,708
    Most wheels and frames are 135mm regardless - some 90s 7 speed was 130mm.
  • naffa
    naffa Posts: 126
    supersonic wrote:
    Most wheels and frames are 135mm regardless - some 90s 7 speed was 130mm.


    Thanks thats really helpful. I've just measured my frame nad it is the standard 135mm.

    I'll now by the wheel I've seen.

    Nathan :)
    Cheers Nathan.
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    You're only using the spacers as the cassette is not as wide as the freehub (which are all more or less the sames on a 135mm hub).

    You need the spacers so the cassette protrudes freehub so it tightens the cassette using the lock ring.
  • naffa
    naffa Posts: 126
    So the spacer fits behind the 'bottom' gear cog?
    Cheers Nathan.
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    That's correct. Closest the spokes
  • naffa
    naffa Posts: 126
    Thanks.
    Thats great :)
    Cheers Nathan.