I am going to replace my Tiagra cassette and chain, but want to use a XT mountain bike one.

The links on the Tiagra chain say 114 and XT 116, the mech is a long one, front chainset is 50 tooth ; but could it all go wrong?

Cheers in advance

but could it all go wrong?

Yes, of course it could. What ratio are you currently running? What ratio are you planning to run?

If the are they are both 9 or 10 speed no problem

If the MTB on has more teeth then the rear mech@ might not cope

How about some details….

You mean you want to fit an XT chain, an XT cassette or both?

And which Tiagra version? 4700?

Crikey cheers everyone!

Basically new block and chain. Want to change to a lighter set up,plus get some more teeth for hills, so was thinking 34 or 36.

The bike is a Spesh Diverge Smartweld A1; 11-32 and 34/50

Going by Wiggle the Tiagra 11-34 is 350g and the XT 11-34 is 323g so very little in it weight wise.
I have a bike with Tiagra 4700 and swapped the OE 11-32 for a Tiagra 11-34, when it was brand new, without changing the chain. Shifts perfectly and the cage looks normal even when going big to big which you shouldn’t ride in.

cheers everyone, I am going to risk it and die like this

https://thechive.files.wordpress.com/2016/05/the-best-british-wrestlers-of-all-time-10.jpg?quality=85&strip=info&w=600

if not i will save it and put on the 29 er ThunderFucker with Big Daddy Enduro Tyres

Wrap the chain round both big rings without going through the rear mech and see if you overlap two or more links.