What do I actually need.?
Currently running slx 9 speed and want to upgrade to 10speed xt.
Do I really need to buy a whole new groupset?

tbh I’d only do it if you need to replace chain/rings/cassette anyway, and groupset is probably the cheapest/easiest way if you need to ask the question

If you want to change everything to XT, you’ll need shifters, crankset, chain, deraileur, cassette

otherwise just a RH shifter, chain and cassette – I think

otherwise just a RH shifter, chain and cassette – I think

And rear mech

Well my chain is well worn that’s all and the cassette has been on for 18 months or so, so I think it’s due.

you can use your current 9 speed rear mech i think.

you can use your current 9 speed rear mech i think.

No, you can’t, hence my earlier post.

Well my chain is well worn that’s all and the cassette has been on for 18 months or so, so I think it’s due.

You get 18 months from a cassette 😯 How few miles do you do?

You get 18 months from a cassette How few miles do you do?

As long as you don’t do anything daft like change the chain, they’ll last forever 😀

It was on my spare bike which has now turned into my main bike !

No, you can’t , hence my earlier post.

Why not? Different cable pull?

Why not? Different cable pull?

Yes

But can you use a 10sp mech with 9sp shifters & 9sp casette?

But can you use a 10sp mech with 9sp shifters & 9sp casette?

No (well not unless it’s a road one)

Ta.
Bum.
Fancied a Zee but didn’t want to change everything else.
Might have to be a Saint then.

10 speed road (sti) works fine with 9 speed xt rear mech on 11/36 where the 10 speed xt rear wouldn’t – is it a different pull, have you tried it?

is it a different pull

Yes, it’s a different pull.

7,8,9,10 speed road and 7,8,9 speed Shimano rear mechs all use the same pull ratio.

10 speed Shimano mtb rear mech uses a different pull ratio and needs a 10 speed Shimano mtb shifter to work.

I would replace the lot, tbh groupset will probably be cheaper than buying 2/3 groupset separately.
You could prob get away with the front mech, but it’s slightly wider which makes setting up a little bit tricky.