Spare wheel question
 

Was thinking about my change of wheels today having gone from 215/45/18 on 7" rims to 235/45/18 on 8" wheels.

This means the circumference has gone up to 2100.8mm from 2044.2mm so my spare is no longer the same as my main wheel meaning it will stress the diffs if fitted.

As my wheels are the OE WR1 wheels and I think OE tyre size will the WR1 spare be the correct rolling diameter?