7 and 8 speed compatibility

[adk]

Hi all,
Im currently doing a build and I'm trying to do it as cheap as possible. Anyway, I've managed to get a frame, forks, bars and so on for nowt which I was quite chuffed with. There's some 7 speed shifters on there but the wheel I was gonna use is 8 speed. Is it possible to get the 7 speed shifters to work on the 8 speed cassette leaving out the lowest ratio or is the distance the cable is pulled by the 7 speed shifter completely different to that needed by an 8 speed system so you kind of end up in between gears or can that be adjusted out?
Ta,
A

 

[Dead Rats]

Should be fine if you set the stops on the mech and the cable tension just right (as you would with a 7 speed cassette of course!) I think the difference between the pull of 7 and 8 speed shifters is miniscule, and of course old skool 7 speed thumbies work on 8 speed cassettes anyway due to their 'hidden' click.

Of course, this being RB you should get a 7 speed wheelset and cassette really

 

[adk]

Of course, this being RB you should get a 7 speed wheelset and cassette really

Cool, many thanks for that.
Well it's kind of half RB, it's my old Mavic 517 but I'm using it's 7 speed cassette on another bike and I'm too tight to buy another 7 speeder!
Ta,
A

 

[jonboy]

Of course, this being RB you should get a 7 speed wheelset and cassette really

Cool, many thanks for that.
Well it's kind of half RB, it's my old Mavic 517 but I'm using it's 7 speed cassette on another bike and I'm too tight to buy another 7 speeder!
Ta,
A

I am pretty sure 1st generation 8 spd was exactly the same spacing as 7 spd? I couldn't tell you if the length of the freehub body is the same for 7 and 8 spd?

Could you change the 8spd free hub body for 7spd one and use the same wheel? I have a couple of 7spd XT freehub bodies kicking around that have hardly had any use and aren't connected to the hub body and could easily be put in the post for just the cost of the postage.

BITD, when 8spd first came out, we used to save weight on our 7spd set ups by using an XTR 8spd 12-28 cassette and taking out the 13t sprocket. That leaves you with a 7spd cassette with exactly the same cog sizes as a 12-28 7spd XT, but a bit lighter and loads better looking.

I have a xtr cassette, missing the 13t sprocket, i.e. 7spd. medium wear, so would need to be partnered with a used chain. never going to use it, so would happily part with it (and a 7 spd freehub) for £7 plus the cost of postage. PM if you're interested.