Just thought I'd give some feedback on my recent experience going from 14" to 15". Had some wheels I thought I'd throw on, don't have time to do bushes or shocks at the moment so thought I'd see what new unsprung would do.
Went from Goodyear NCT's in great condition, about 4mm or more to the wear bars on them. They were 185/60R14. Mounted on factory 45p hollowspokes, 14x6.
To GT Radial Champiro's in front and Kingstar K106 rear, both about 2mm from wear bars. They're both 195/50R15's. Mounted on 15x7 ROH Reflex's, about 40p.
The 15"s are about a kg heavier than the 14"s.
I was expecting the car's road manners to go out the window with the heavier unsprung, less grippy, more worn tyres. But turn in was sharper, car was more settled mid corner and on corner exit, and everything was more predictable
I was mostly impressed by the turn in - very similar to my race car (which has had a lot development for corner entry)
Unfortunately, I think I need the wheels to be balanced and possibly need to purchase hub-rings as the wheels aren't hubcentric at the moment. Had a severe case of the 65mph shimmy.
Will report again once I get lighter 15"s and better rubber. (And the ROH's and hollowspokes will be up for sale as soon as I find something.)
P.S. Kingstars are atrocious tyres, and I would not recommend them at all, they're loud, have very low limits and are completely silent when they let go. This was in the dry too
keeps life interesting.
