Tyres

Anybody spotted the tyres on the new caterham 7. 245/40 15 rears and 195/45 15 fronts. They are Avon CR500s......

Caterham have used Avon CR500s for a while now....in fact Avon use the Caterham as an advert in magazines to show how good their tyres are. Had a set on my race car a couple of years back.....they are excellent tyres. Sadly they cost a fortune and they are on the wrong list in the motorsport year book so I cant run them on the Alpine.

They wre 13 inch. The CSR has 15 inch wheels,its a new size for CR500s.I know they're not blue book for road cars but top trackday tyre and still cheaper than OE Michelins

..but 245-40-15 is way too small for a GTA....

..but 245-40-15 is way too small for a GTA....

But it would be geared better for acceleration (60 in under 5 anyone?)!
I use lower profile tyres on the original rims on my XR2i for short circuit racing and it's defo much quicker off the line.

Clee, what about trying that in the comp?

It wouldn't make the rear hit the ground or anything, would it?

Rolling radius only is 11.5mm less than 45 section and circumerfence about 4% less, i.e. less of a difference than going from 245/45 15 to 245/40 17s

I make it more than that. if you stood the 255-45-15 next to the 245-40-15, it would be 33.5mm more in overall height..

255/100 x 45 = 114.75mm sidewall
245/100 x 40 = 98.00mm sidewall

You're right. I worked out 245/45 v 245/40 not 255/45 v 245/40

But would that make it hit the ground if you're running standard suspension?

Liam, if the sidewall is reduced by 16.75mm, then the rear of the car will be lowered by the same amount, well less than 1 inch, so I'd guess it will be ok.

..problem is though, is, that sized rear tyre is only 0.5mm smaller in diameter than the front tyres...it would look a bit silly!

In my experience putting lower profile tyres on the standard wheels on any car does the following things, makes it accelerate better (driven wheels only obviously, lowers it - sometimes this looks ok sometimes not, ruins the ride comfort, and often makes the car horrible to drive due to the change in suspension angles and camber etc. I think a GTA would look ridiculous on smaller rear wheels as the standard wheels are a bit lost in the arches anyway and it would also exacerbate the GTA's slightly nose upward stance

I'm with Tony.....rubberband profile tyres like these would make a GTA on standard wheels look horrible. Theres' be less filling the arches and would exagerate the bland design of the wheels. Yes it would improve acceleration but not so that you would notice without an accurate measure.