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Hi all,
Has anyone used 14" R spec tyres and then gone to 15" R specs without any other changes?

I realise that 15" with the lower profile ratio will handle track work better but I'm interested in finding by just how much?

I'm in the position of needing either 2 x 14" Dunlops or spending the extra money and buying 4 x 15" Toyo's or Dunlops,
as next year is going to be first year doing a full series and not having any experience driving other than club days, I'm not sure if spending the extra $800 is really necessary or if I'm better off running what I've got and getting used to the car and racing ( at the back), and spending time learning from others the correct lines etc.

Thanks

Terry

I had 185 x 14 yokohama's r spec tyres and went to 205 x 15's r888's. I did go a bit faster with the 15's, it was noticable out of corners where it had more grip. But even after spending about $3,000 on upgrading to 15x8's and nb8b brakes and a retune with another 20kw's. The times only went from 1:57 to a 1:55 at phillip island. Even now after taking more weight out of it and driving a bit better i have only dropped another 2 seconds to 1:53. So it takes a fair bit to make a difference to your lap times. Not just slightly bigger tyres.

Thanks for that info Lightyear.

I think I'll keep my money in my wallet and just get some experience with the car the way it is.


Terry

Good idea. I think I would have been much better off starting on 185r14s. Cheaper, lighter and much less fuss. Going to R-Specs gives you 1 or 2 seconds, much better control and fewer heat problems. Varying the size of the R-Spec only gains you a tenth here or there.

wheel diameter has nothing to performance specs. overall tyre diameter and width is what you need to concern yourself with. and matching that tyre width with the rim width.

14x6 w/ 185/60r14 tyres vs 15x7 w/ 205/50r15 tyres... even though the tyre diameter is increased effecting accelleration, the extra rubber on the track from the wider rubber allows higher speeds thru corners. it's all a balancing act really.

and as above, going for the 14s tyres is most likely the better option. the smaller the tyre, the cheaper it is.