9spd / 10spd compatibility

everydayimriding

I'm looking to lower the gearing on my cx bike by putting on my MTB 10speed cassette.
I've been advised to get a 9speed rear mech as this will work with my current STI shifters.

But which chain should I use?
The 10spd Shimano I usually pair with the cassette - would it work with the 9spd mech and cx crankset?
Or a new one, in which case 9 or 10speed, road or mtb (if there is a difference) ?

Many thanks in advance

jimothy78

You'll need a 10-speed chain to fit a 10-speed cassette. No problems with crankset or front mech. Then you'll need either:

a) a 10-speed MTB rear mech and 10-speed MTB shifter
or
b) a 9-speed MTB rear mech and a 10-speed Road shifter

everydayimriding

Great, cheers, i'm going with b)
So does it matter if the 10 speed chain is the XT HG95 or the Ultegra 6701 ?

njee20

Notionally they are very slightly different. In reality no.

jimothy78

everydayimriding wrote:

Great, cheers, i'm going with b)
So does it matter if the 10 speed chain is the XT HG95 or the Ultegra 6701 ?

No, but you're better off going for a KMC X10

gtd.

I'm converting my Tourer/Cross bike from 10s Road cassette to 10s MTB. Was a 105 triple groupset, 5703 STIs with a 105 RD-5701 GS rear mech and Tiagra 12-30 cassette.

As jimothy78 said, I've changed to 9 speed mech (XTR RD-M972 SGS). Shortened the gear cable outer as it is a Shadow mech, see http://si.shimano.com/php/download.php? ... 01-ENG.pdf and it works perfectly with the 10 speed road shifter.

I'd have fitted a lower model SGS (MTB Long) mech but I got the XTR for a good price. I Haven't replaced the cassette yet as I need to order a new chain can't find 10 speed chains locally.

gtd.

You might want to check the chain length, mine has gone from 114 for a 50t chain ring 30t sprocket to 118 for a 50t chain ring 34t sprocket. Most chains are only available in 114, some 116, Sram do the PC1071 in a 120 an KMC do 10 speed E bike chains with 136 links

njee20

To be fair that's a very unusual combination.