I run 195/50R15 on 6.5" wheels. I had 205/50's on them previously, but they were from a previous owner that was not into performance. There is LESS sidewall flex now. Partly due to the narrower tires on the car now, but mostly due to the sidewall construction of these Yokohama ES100's. They have pretty stiff sideways in general. I plan on going to 205/50's again, but only after I get another set of wheels (15x7) just for track events. Whatever they will be, they will be more suited for the track than these ES100's I have now. :?
How do I know there is less sidewall flex? I attend a monthly gymkhana over here. Going from junk to fresh rubber turned up the wick quite a bit. I'm not sure how events similar to gymkhana in Japan are in England, but they are tire killers over here. I wouldn't want it any other way. :lol: