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PostPosted: Thu May 09, 2013 9:18 pm 
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I need some advice (again)

I currently have a rear hub (M900) with 8 speed cassette, with an XTR M900 rear mech and Shimano M008 shifters.

Question is, I've a new wheel I wish to replace this one with (a Phil Wood hub) but it is a Freewheel rather than cassette hub, can I use a 7 speed Freewheel with the XTR M900 Rear Derailleur and M008 shifters?

Or would I need to change the shifters to 7 speed ones?

if so, would Suntour XC Pro shifters be appropriate?

Please let me know, as another option would be a 8 speed freewheel - but these weigh even more than the 7, and aren't as good quality.

Thanks


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PostPosted: Thu May 09, 2013 11:51 pm 
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I'm sure someone else will confirm but for now I don't think the freewheel/shifters are compatible because the spacing between the cogs is wrong; 8/9 speed are the same if memory serves me correct but 7 are wider?

I for one certainly wouldn't bother with a freewheel, no matter how fancy the hubs...


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PostPosted: Fri May 10, 2013 6:02 am 
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We_are_Stevo wrote:
I'm sure someone else will confirm but for now I don't think the freewheel/shifters are compatible because the spacing between the cogs is wrong; 8/9 speed are the same if memory serves me correct but 7 are wider?

I for one certainly wouldn't bother with a freewheel, no matter how fancy the hubs...



Thanks man
The 7 speed Dura Ace freewheel will not be any different to a 7 speed Shimano cassette

So would a M900 be useful with a 7 speed cassette and 7 speed shifters?


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PostPosted: Fri May 10, 2013 7:26 am 
retrobike rider
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The rear much will work with whatever.
I'll leave the rest to you.
But keep shifters with the correct cassette else you are bodging just to get lightweight.
Personally I'd use the M900 8sp setup or use an 8sp freewheel if the hub can be space red for it. I would ignore the weenie fettish (that I have) at this point.
Use the 7sp on something else.

But
7 is close to 8speed and with careful adjustment and blazon use of the floating jockey you'll probably get it to work.
Or use some lovely light srt500/600's or if your a thumbie lover then use them.


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PostPosted: Fri May 10, 2013 8:17 am 
King of the Skip Monkeys
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http://sheldonbrown.com/cribsheet-spacing.html


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PostPosted: Fri May 10, 2013 8:35 am 
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Thanks guys
Cleared things up
I think I'm going to go for 7 speed freewheel as the hub is 130mm so fit for 7 speed MTB according to Sheldon link.
And suntour xc pro 7 speed thumbies.

Please advise if this combo will be ok

(And I always have my present m900 wheels plus M008 shifters to put on if things don't work out )


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PostPosted: Fri May 10, 2013 1:42 pm 
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7 speed cassettes and freewheels are interchangable as the spacing is the same, even Campag will work (give or take assuming you are not looking at Regina Syncros or the like). 7 and 8 speed cassettes and freewheels are interchangable as they use spacing that is basically the same (slack will be taken up by float on the jockey wheel).

Big tip is to set the gears up with the chain on the middle cog of the cassette, not on the smallest or largest. That way you make the most use of the available float on the jockey - ie if the spacing is .2mm out on a 7 speed cassette on an 8 speed shifter and you set it up on the lowest cog then the difference will be .2x 6 = 1.2mm max when you hit the large cog, but if you set it up on the middle it will only ever be .2 x 3 = .6mm max at each end which can easily be taken up by float.

The only thing that you have to be careful with are the shifters and mech. If you use a 7 speed cassette then you could accidentally over shift unless you wind in the limiter screws on the mech.


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PostPosted: Fri May 10, 2013 2:53 pm 
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pete_mcc wrote:
7 speed cassettes and freewheels are interchangable as the spacing is the same, even Campag will work (give or take assuming you are not looking at Regina Syncros or the like). 7 and 8 speed cassettes and freewheels are interchangable as they use spacing that is basically the same (slack will be taken up by float on the jockey wheel).

Big tip is to set the gears up with the chain on the middle cog of the cassette, not on the smallest or largest. That way you make the most use of the available float on the jockey - ie if the spacing is .2mm out on a 7 speed cassette on an 8 speed shifter and you set it up on the lowest cog then the difference will be .2x 6 = 1.2mm max when you hit the large cog, but if you set it up on the middle it will only ever be .2 x 3 = .6mm max at each end which can easily be taken up by float.

The only thing that you have to be careful with are the shifters and mech. If you use a 7 speed cassette then you could accidentally over shift unless you wind in the limiter screws on the mech.



Thanks very much for that man :)

It'll be XTR M900 rear mech and M900 front mech, a 7 speed Suntour or other quality Freewheel and Suntour XC Pro thumbies.


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