wheels and tyres

[city_racer]

i race my little city and i was curious about the wheels and tyres

currently it has 175/60/r13 i'm pretty sure. i would like to go to 14s but if they are not going to make a huge difference i wont bother. wats the best size to help with performance?

thanks

[el roacho]

I used to have 175/70R13 on T2 rims on my T1. Then i got a set of 14X5 Daihatsu Charade Detomaso rims and got a set of directional Nankang 175/65R14 tyres on it which made it handle heaps better. In the wet the wheels used to spin heaps at 80kmh in 2nd. Now in the wet I hardly get any wheelspin and understeer has been greatly reduced with bigger wheels, but that's also due to the fact my old tyres were cheap and nearly bald at the front. The unsprung weight doesn't appear to be increased much as acceleration is the same. I only had minor guard rub going around corners with 6 people in my car so 14X5 is a good size on a City without having to put flares on or roll the guards. Although for serious race use you would probably want 14X7 for optimum traction but then you would have issues with the tyres not clearing the guards, especially if it's lowered. Go for a set of lightweight rims as well as you can't afford to increase the unsprung weight much as acceleration would suffer.

[James]

el_roacho you seem confused about the effects of unsprung weight. The main effect of unsprung weight is on handling not acceleration. When the unsprung part of the suspension weights more it has more inertia and thus moves the car more when it moves up and down. There is more to it than that but I can be assed explaining it, try a google

You probably want to go for some lightweight 13" mags for racing, and go for some 205/60r13's or something, this will give you lots of rubber and keep your unsprung weight and your rolling diameter down, which is important for your handling and acceleration respectively. You may have to play around with the offset to get those tires to fit nicely. One option is to have some standard steel rims widened, these still end up pretty light and you can choose your offset to a certain extent.

Those tires can be a little tricky to find but you should be able to get hold of some, they are popular for some older rwd race cars like escorts and such.

If you are going to fit big brakes 13"s may not fit and then you may want to go for a forged 14" or similar, this may make it a bit easier to get tires too.