Alga,

I have put 15" wheels on my T25 camper(standard wheel size is 14"), I worked out the rolling radius based on tyre sizes etc as didn't want to alter the gearing or affect the speedo BUT for some reason even though there is only a few mm difference in the sizes my camper now sits 25mm lower.
I was then expecting the old fella to rev out after seeing how much it had been lowered as obviously it must have changed the gearing way too much......but no, if anything it's better now as pulls away easier and flies up to a staggering 60mph and settles down rather than sat screaming it's head off...........


So Mr Alga maybe it's just fashionable to have low profile fat tyres....I really don't know