Has anyone upgraded gen 4 tyres without going bigger?

Busta wrote:

I have a set of brand new Gen4 wheels with the 195/80 Dunlop Grandtreks on I've never fitted. I have had a set of BFG 215/75 all terrains on my car for 5 years. Both sets are on standard steel rims. I'll swap them over and see what difference it actually makes.
 

I will be really interested in this comparison.  I am poised to buy a set of tyres for trials and had settled on 215/75r15, but they are out of stock with my local fitter.  The alternative is 195/80r15, which are roughly the same diameter but 20mm narrower, although if there is no difference in tread on the ground when you air down it does make sense to go for the lighter tyre.

The surface we have at our local trial varies, today it was mostly soil, some clay, some mud and the odd bit of concrete.  I ran in to loss of grip today on my Worm-Drives, but actually not as bad as I thought I would, so not sure if the narrower tyre would have been better or not?

Robin