10 speed change with 9 speed rear mech

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This topic has 13 replies, 9 voices, and was last updated 12 years ago by clubber.

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10 speed change with 9 speed rear mech
vodkatart
Free Member

Hi everyone,

I know this has been discussed several time but each topic has had a different take on the situation.

I have a:

10 SP Dyna XT shifter,
RD-M772 rear mech (9 speed)
11-36 rear cassette (10 speed)
10 SP SRAM chain.

Should this work? will it work? After placing all the equipment on the bike i am finding that the rear mech doesn’t sync quite right it will change a couple of gears but then goes out of sync for the next one before falling back in line. It does this twice over the whole cassette. I though the rear mech would sync inline with the shifter, but this doesn’t quite fit. If it is that it wont work, for my own sanity can someone explain why? not just it wont. Is it the cage size, shape or just how the new 10 SP mech (rd-M773 i believe) works.

Cheers in advance

Posted 12 years ago

simondbarnes
Full Member

It won’t work. You need a 10spd Shimano MTB mech for it to work. The 10spd mtb mechs are designed to work with a different cable pull to the 9spd mechs (and 10spd shimano road mechs)

Posted 12 years ago

bikewhisperer
Free Member

10spd has a different cable pull, so get a new mech and you’ll be fine. Your 9spd mech will be sufficient payment for this advice. Please email me for delivery details 🙂

Posted 12 years ago

FGF 701 The Hydrate Or Die Edition

vodkatart
Free Member

:-), of course in return for a 9spd would a 10spd. Whats anyone opinion on the 10spd SLX. doesn’t lok as nice as the xt but is their any real difference, weight?

Posted 12 years ago

bikewhisperer
Free Member

Absolutely! Ten spuds are in the packet and ready to go. What’s your address?
It won’t change your life having SLX vs XT. My approach has always been to get the cheaper, trash it, and then get the more expensive if I think it’s cheapness was the reason it failed.

Posted 12 years ago

jamesco
Full Member

Would ov been inclined to check over the indexing before giving in , if you only had a couple of ‘off’ changes across the whole block you were pretty close to succes I think, I have 9spd Deore mech working a 10 spd MTB cassette on a road bike using 105 shifters so a bit of leeway is in the system, try the barrel adjustment to fine tune the indexes.

Posted 12 years ago

boriselbrus
Free Member

It does not work.

Think of a rear mech as a lever which pushes the chain across the cassette.

The further the cable attachment point is from the fulcrum (pivot point), the more cable you need to pull for the other end of the lever to move the full width of the cassette.

The distance from the attachment point to the pivot point is different for 9 speed and 10 speed.

Posted 12 years ago

jamesco
Full Member

Think of the mech moving across a given space 5/6/7/8/9/10/11 speed the gross distances are similar with the big cassettes, it’s the actuating lever which decides the amount of movement per shift plus a bit of index fettling with the barrel adjusters combined with the limit stops, so although I agree not all mechs and shifters are compatible, many Shimano are and it’s worth a bit of fettling to be sure.

Posted 12 years ago

Mister-P
Free Member

Sorry Jamesco, Boris is correct on this. The reason your set up works is the cable actuation ratio of 9 speed MTB and 10 speed road is the same. 10 speed MTB is different so you do need a 10 speed rear mech with 10 speed shifters.

Posted 12 years ago

takisawa2
Full Member

9spd mech wont work with 10spd cassette & shifter. I tried. 😥

Whats anyone opinion on the 10spd SLX. doesn’t lok as nice as the xt but is their any real difference, weight?

Bit clunkier in use but other than that nothing. Bit of weight in the SLX cassette though, if your going to scrimp I’d go XT cassette & SLX mech.

Posted 12 years ago

clubber
Free Member

I’m intrigued to know if something like the hubbub fix could be made to work with the OP’s setup.

http://www.ctc.org.uk/desktopdefault.aspx?tabid=3946

Anyone know off the top of their head the difference in cable pull between 9 and 10 speed mtb?

Posted 12 years ago

boriselbrus
Free Member

For Shimano it’s simple:

All 7,8 and 9 speed MTB and 7,8,9 and 10 speed road rear mechs work with all 7-9 speed MTB and 7-10 speed road shifters.

10 speed MTB mechs only work with 10 speed MTB shifters and 10 speed MTB shifters only work with 10 speed MTB mechs.

It’s not the distance the mech has to travel that’s the problem, it’s the amount of cable the shifter pulls to achieve the travel.

For example, a 9 speed shifter may pull 5mm of cable per shift (it doesn’t, but go with me), so when the 9 speed mech feels 5mm of cable pull, it moves between 2 adjacent sprockets. If a 10 speed shifter pulls 10mm of cable per shift then a 9 speed mech will move across twice as far, missing out one of the sprockets. So a 10 speed shifter will have a shorter lever on it so it moves a shorter distance.

Hopefully that’s clear!

Posted 12 years ago

lovewookie
Full Member

According to sheldon brown dyna sys requires more cable pull.

Clubbers solution may work, or it may be the other way round, I’ve not got my thinking head on today.

Posted 12 years ago

clubber
Free Member

more cable pull means a setup similar to the hubbub one. of course the limearoty of the steps in cable pull may be an issue.

Posted 12 years ago