Mrs Julioflo is getting back into riding again, but has found her Specialised Vita does have high enough gears for some of the moorlands hills around here.
It’s 8 speed, so I bought a new 32t 8speed cassette and new chain thinking it would solve the problem. But went to fit these tonight and the current rear mech, a Sora, doesn’t seem to have enough capacity for the new cassette. The old cassette is 25t.

So would one of these have enough capacity?

Alivio rear mech

That should work ok.

The new Sora mech will work up to 32t i believe.

£19.99 on CRC or around £14 on Rose.

Short cage would be better and i think you can run it 8 speed?

Thanks. Felt a bit of a dumbass that I had overlooked rear mech capacity. The bike has basic shimano 8 speed shifter & V-brake lever combos. I just want to check they will be alright with the alivio rear mech as well?

Yeah, Sora 3500 should work too. SS version probably not great if it’s with a triple, better off with the GS in that case.

I just want to check they will be alright with the alivio rear mech as well?

Yes, they will

Brilliant. It’s with a triple so Sora 3500 GS def. Before I purchase, you guys sure it will run 8 speed okay?
Thanks
Jus

I’d be a bit wary depending on what year the mech is, we’ve had a shedload of bikes from last year that were fitted with them, and had trouble getting enough B-tension to clear the largest sprocket(11-32 cassette).

It’s not just a mattter of how big the largest cog on the cassette is.
The general rule is to find the difference between the largest and smallest cogs on the cassette, do the same for the chainset, then add these together to find the required derailleur capacity.
Check the shimano tech docs for the capacity of any particular derailleur.

Don’t forget chain length.