10 speed rear mech on a 9 speed system, is it possible?

[sic_nick]

I am currently building up an On One 456SS and want to put on one of those clutch mechs that are available on the 10 speed groups but if I replace the jockey wheels for some older and wider 9 speed ones it should work as a 9 speed mech shouldn't it? I presume Shimano still have the same cable pull:travel ratio as before or am I going to have issues. I just feel the clutch mech will be a good thing on a burly hardtail to try and limit or even prevent me dropping the chain, I still have an old DCD on my other bike and that does a great job keeping the chain on. I will be running a 3x9 setup too.

I have run 8 speed rears on 9 speed systems and vice versa in the past and it has been fine so if anyone else has any experience on this I would appreciate it.

 

[fagin]

Nope- different pull ratios. (7,8 and 9 are the same, not 10)
I believe you can do it with a Sram mech Shimano shifter and a spacer.

 

[sic_nick]

Sram mech and shimano shifter? thought the Sram ratio wouldn't work with a Shimano shifter!

 

[reanimation]

I researched this lightly myself, A chap redrilled a new Zee mech, I decided not to gamble, bus I have a bunch of chain devices and little chain flick issue at present, might Ten speed teh Kinesis though hmm, or if a SLX mech breaks!
ah, this is the spacer option? http://www.pinkbike.com/forum/listcomme ... did=148662
http://bb.nsmb.com/showthread.php?t=153122 Drilled!

 

[sic_nick]

I like that with the brass spacer, found these pics using zip-ties, it scares me a little to do that knowing how easily they can fail when they're that thin. I have just been on CRC and ordered a 10 speed mech, cassette, chain and shifter so I can finish it off and know it will work as I dont have access to sort out a nice little spacer like that right now.

 

[fagin]

Sram mech and shimano shifter? thought the Sram ratio wouldn't work with a Shimano shifter!

They don't, hence the spacer, but looks like I got it back to front.

 

[xerxes]

Re:

I was looking at this: http://sheldonbrown.com/cribsheet-spacing.html#overhang

The difference between the sprocket centres on a 9 speed cassette is 4.34mm and 3.95mm on a 10 speed, so the cable needs to be pulled 9.4% less per click.

Has anyone thought of modifying a thumb shifter by making the groove in which the cable runs deeper which will make the diameter of circle around which the cable wraps smaller and therefore pulling less cable per click?

If you measure the original diameter you could calculate the circumference, then calculate a circumference 9.4% smaller and from that new circumference calculate the new diameter to work out how much deeper the groove needs to be. Easy.

 

[hamster]

I have done it the other way by filling the groove with insulating tape.

 

[The History Man]

Nice thinking on the groove thang.

 

[hamster]

If you are thinking along the thumbies route, remember that Shimano didn't change the cable pull for their road 10 speed. So a Paul's thumbie adaptor ( or cheaper equivalent from SJS Cycles) plus a road bar end shifter will work out of the box.

EDIT: no it won't as the 10 speed mech has a different pull per click. Sorry, got things inside out. You need to do something like a hubbub mod on the clamping, as in the little brass plate. Oops.