Currently running SRAM Rival 1x 10-42 on my gravel bike and I am planning on buying a set of lighter road wheels with road tyres and an 11-32 cassette.

I don’t really want to go 10-42 as it means using XD-Driver hub and a far more expensive cassette but…

Will having the rear mech set up for 10-42 and then putting a rear wheel in with an 11-32 ratio cassette effect the indexing of the gears & high/low limits…? I think it might. If so do I have no option but to bite the bullet and buy an XD rear hub and matching 10-42 cassette?

I’m fairly sure you’ll have issues as the top jockey wheel will be significantly further from the largest cog on the cassette with the 11-32. I’ve only ever done this with the same sized cassettes as it keeps it simple (but expensive if using an XD driver).

I do it on the road bikes where I switch between rear wheels with 11-21, 11-28 and 11-32 cassettes and I’ve never had a problem. All 3 wheelsets have Shimano hubs.

I have two wheel sets for my gravel bike.
Cx1 force shifter and mech. One wheel set has an 11/40 xtr cassette and the other has an 11/32 ultegra. The only difference is a cassette spacer on the freehub behind the xtr cassette.

No changed needed to the mech for both to work correctly and shift perfectly

Great news!

on and on – do you have disc brakes? My next question is do you get brake rub using different discs?

A touch, but only because the discs are thicker on the wheels with the Xtr cassette. They tend to be used for the mountain rides I do so I want as much stopping power as possible.

The road wheels are run with lightweight rotors which are a tad thinner.

Usually a few pulls on the lever will recently the pistons so any rub goes away quickly.

Just be careful of the low gear stop screw. You don’t want to overshift into the spokes. There are small tolerances involved. But I swap 11×32 with 11×23 all the time with my 1xXX without problems. Hubs are DT and mavic.