I’ve a 10 speed SLX mech (medium or long cage, not too sure, think it’s long) at present and a standard Deore casstte (11-36).

Do i need anything special to swap the cassette to a SunRace MS3 10 speed (11-42).

Seen comments before about extra links and such.

If your chain rings staying the same size you’ll need some extra links in the chain for sure. Maybe a longer B screw or something like a Goat Link too.

I had to install a Goatlink for a very similar set up. I used a med. cage mech.
It worked OK with the standard link, but the shifting is now so much better.
As above, longer chain too.

APF

Cheers qwerty, think i’ll be dropping to 30t (32 at present) for the up-coming Jenn ride.

I’ll get the goat link and cassette.

EDIT: Cheers Alex.

Same setup for me and while it worked (medium cage) I fitted a Pilo S10 (goatlink copy) and got improved shifting.

Apologies if this post has an egg sucking quality to it but you have an 11 speed shifter, yes?

30T chainring and 11-40t sunrace cassette (9spd) on mine from a 32 chainring and 11-34 cassette. Didn’t need anything else at all with a standard long cage slx rear mech

Apologies if this post has an egg sucking quality to it but you have an 11 speed shifter, yes?

What whaaaaaaaat!?!?!?

Why on earth would you need an 11sp shifter with a 10spd mech and cassette? That’s just silly.

With a 30T ring and Long cage rear mech, I just fitted the 42T cassette and it worked fine to be honest.

I have a 30t ring, 10 speed slx mid cage mech and the 40t sun race cassette. Works fine with no extra tinkering. I think sunrace provide an extra long b screw with the 11-42 cassettes?

I used a One-Up cage for mine and it works fine.  And it’s a pretty green colour.

Definitely a new chain if you’re doing it properly and for the cost of a 10sp chain vs the pain of a broken chain I would.   If you don’t already know how to correctly size a chain, check the Park guide (apologies if this is egg sucking but comments about extra links make me wonder).

Derailleur cage length is important for ‘chain capacity’. For a 1x it’s almost redundant.  Ability of a derailleur to cover a cassette is only accidentally to do with cage length.  A GS (Medium) should be fine.  The top jockey position is more important- this is what you’re adjusting with b screw, goat link, radr etc.

Every combination of frame, derailleur and cassette is different and there’s a bit of experimentation needed unfortunately. Unless you know someone with the exact combo, if money is tight I’d try without the goat link etc first and see what happens.  You might be happy with it just on the b screw…

I managed with an XT Shadow long cage mech and 32t chainring and 11-42 Sunrace. Shifting is pretty good. Worth a go before you shell out on a goatlink.

M7000 medium cage SLX mechs were 40 quid at CRC I think, and supposedly play nicely with 10 speed setups and wider range cassettes (up to 11-46) I believe.  Some of the solutions for better 10 speed shifting cost a fair chunk of that, so you could invest in that and keep the old mech back as a ride-saving spare.

I run the same cassette and a medium cage SLX mech in a Solaris. It was ok, the goatlink has improved it though.

I’ve got a medium cage SLX mech and the 11-42, no issues what so ever – shifts perfectly.

My setup (SLX + 42t cassette) wouldn’t work without modification. I got a Rad Cage but Goat Link would likely have worked just as well

pilo link on mine. works brilliantly.

Cheers one and all, chain, goat link, jockey wheels (they were well past best), cassette and 30t ring on the way.

This was an expensive day.

I use the 10 speed 11-42 with a X9 mech without any any mods, think I just got lucky!

smokey_jo, How are you finding the 9 speed 11-40? I’m thinking about fitting one of these to the old hard tail.

The 11-40 is perfectly fine, gaps aren’t so bad, shifts fine and 450g weight is genuine. Coupled with a 30t at the front on my 26er I rarely needed anything lower that would have helped much on my last few rides in Lakes and Dales.

You can spin out 30/11 on a downhill fire road but WGAS, my racing days are long over.

Thanks. Exactly what I needed to hear, I’ll get one ordered!