Yup Riff Raff..this was covered in a thread a bit less than couple of years ago when the ORW turned 18.
IIRC , actual rolling test showed a difference of just under 9%...
So given larger tires were fitted at about 13500 miles...
..'real' miles are at aprox 20100
Gotta say...a Foxfire with 14,000 is amazing...coke or not...!!
jo