shimano deore xt derailleur query

Assuming you have an older model XT rear derailler that was designed specifically for 7-speeds, it might be touchy just to get it to work with an 8-speed system, let alone 9. The reason is the pulley wheels on the older 7-speed were wider, and had about 0.5mm more side to side play then the 8-speed derailleurs. 0.5mm may not seem like much, but can really effect the crispness of shifting.

The easy answer might be to just buy a set of 8-speed pulley wheels and bolts, but you might encounter a problem with the back plate for the pulley arm. On the lower end of the back plate, there is a flare (probably to help shield the pulley wheel from mud), and the flare might not fit with an 8-speed pulley wheel, it might grind the edge right into the side of the pulley wheel.

Since from a full 7-speed system to an 8-speed (or 9-speed) system will require a new rear hub, cassette, chain and shifters, why not just throw in a new rear derailleur while you are at it?

Cheers,
Juba

ahmed0 said:

I'm currently running a 7 speed cassette with spacers and I am wondering if I can go directly up to a 9 speed or if the deore xt can only handle an 8.

If you are asking if an older Deore XT derailer will work in an indexed 8 or 9 speed system; the answer is yes.
You would have replaced hub, cassette, chain, and shifter(s) to accomplish the other part of the conversion. You would see a shifting performance and smoothness by replacing the old derailer with a new 9 speed one, but the old one will work.

ahmed0 said:

I'm currently running a 7 speed cassette with spacers and I am wondering if I can go directly up to a 9 speed or if the deore xt can only handle an 8.

It should work (I've done it before). As previously mentioned the performance will not be as great, but it could get you through. The 9 speed cogs/cog wheels are thinner than the 7 or 8 speed and the chains allow for these thinner pieces of metal by having smaller areas for the cog teeth to fit into. The chains themselves are somewhat thinner and so forth...

Good luck.

K.