7 vs 8 vs 9 speed hubs

stowei

I've picked up an old bike to bring back to life. Its got a 7 speed cassette but having stripped the bike down I am wondering whether it is really a 7 speed hub or not. I've searched the forum but cannot find out how to tell the difference between Shimano hub specs. How can I tell if its a 7, 8 or 9 speed hub please? The only marking on the hub seems to be just 'Shimano Deore', and I'm pretty certain that the wheels are not original to the frame.

Thanks


Ian

Gingersaurus

Count how many gears there are on the hub.

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stowei

So if it has a 7-speed cassette on it (which it does) then it must be a 7-speed hub, is that what you mean? I don't usually work on mountain bikes or Shimano, only Campag road bikes, and with those its definitely not so simple. I wondered whether it might have been possible that in spite of having a 7-speed cassette it might actually have been a later hub designed to accept 8 and/or 9 speeds.

Ian

lachoman

7-speed hubs have a narrower freehub than 8/9 speed, which are both the same. 7 speed cassettes can be used on 8/9 speed hubs but only in conjunction with a 4mm wide spacer. If there was no spacer and just a 7 speed cassette then it must be a 7 speed hub which can only be used with 7 speed.

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stowei

Thanks - that makes more sense. There is a large spacer so it must be a later hub. Are 8/9 definitely the same hub - I read in another post that 9 speed cassettes can bottom out on 8 speed hubs. Will there be anything at all that will allow me to distinguish whether the hub was originally manufactured with 8 or 9 speeds in mind?

And now that I'm thinking that I can move up to at least 8 and maybe 9 speeds, what about the rear derailleur? It is currently servicing the 7 speed cassette but I cannot find any difference between it and the rear derailleur on my son's 8-speed machine. (Both XT, neither have any speed range quoted.) Apart from trial and error is there any way I can discover if it has a big enough range for 8 or 9 speeds? Presumably the shifting concept itself is simailr at Campag road with the different cassette spacing being a function purely of the shifter; the only issue with the derailleur being whether it has enough range between the stops.

Thanks again

Ian

nicklouse

8/9 are the same.

nick
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