Jonty

Afternoon all.

Although I've posted here on behalf of the missus before, as I'm soon to pick up my own MY00 UK Turbo in a week, I'll consider this my first posting.

The MY00 is completely stock... along with its 16in wheels and 205/50/16 tyres. I'm wondering whether I can get away with running wider tyres all-round, but of course at the same time keep the rolling radius as close as possible.

With my MR2 Turbo, this has come in very handy in the past;

http://www.miata.net/garage/tirecalc.html

To throw an example at you, I could potentially run 225/45/16 tyres as long as a) rubbing doesn't occur, and b) I'm not forgetting anything stupid here..(?)

My MR2 has 16in wheels with a 7in width and I've got 225/45/16 Eagle F1 rubber on the rear which fits fine and wears fine too.

Your oppinions are more than welcome.

Cheers,

Jonty.

Mike Tuckwood

Yes you can, but you won't see a major gain in grip levels simply based on a width increase alone.

The contact patch of the tyre will change, it will be slightly wider, but will also be slightly narrower as well. End resul is same amount of rubber in contact with the road.

No doubt SDB will be in here soon to explain why in greater detail. This thread will now grow to circa 30 pages.

Mike.

Jonty

Thanks for that Mike.

I must confess, contact patch is a subject which I've never really got to grips with, if you'll pardon the pun. I can understand 'wider' but not quite sure about 'narrower'. My basic understanding is that dry conditions would benefit from slightly more rubber on the road, however there could be adverse results when wet, i.e. more rubber + weight of the car = slightly harder to cut through water than before.

No doubt rumour has it that Subaru spent millions in the design of the Impreza so I'm sure 205/50/16 tyres were fitted for a reason and I'd only consider something wider if there was to be a good gain. On the flip side, I can get 205/50/16 Eagle F1s fitted for £105 each as opposed to £130 for 225/45/16.

If in doubt, use a calculator.

Regards,

Jonty.

Mike Tuckwood

Yeah, contact patch is a function of the weight of the car against the pressure of the tyre, you can increase the footprint by lowering the pressure or increasing the weight, the dynamic size and shape of the contact patch changes in differing loads and circumstances anyway.

It's quite complex, certainly too much so to say which is "best".


Mike