Anyone running larger than 225 profile tyres?

Anonymous · December 12, 2004, 23:01

Hi all,
As it says, anyone running wide profiles and does it improve handling and grip?
And anyone running wider than 245's on the rear?
Cheers...

Slacey · December 13, 2004, 08:36

The widest I have run is 225's on the rears and although grip did increase (demonstrated quite well at North Weald) the overall hadling suffered slightly with 215's (IIRC) on the front.
I know of a couple of owners who have run 235's at the rear, but haven't heard of any running larger than that - I think you would start running into problems with 245's TBH.

Anonymous · December 13, 2004, 09:46

Quote from: "Slacey"The widest I have run is 225's on the rears and although grip did increase (demonstrated quite well at North Weald) the overall hadling suffered slightly with 215's (IIRC) on the front.

How did the handling suffer - I'm interested to know how grip improved yet handling suffered? Was this simply down to running 215's on the front reducing the 30mm front/rear split?

QuoteI think you would start running into problems with 245's TBH

Would this be due to rubbing or poor handling?

Jap GT300 · December 13, 2004, 10:43

I am running 245/45/17 in the rear and 225/45/17 in the front

They are Yoko grand prix tyres (Japan Only)

Bongo · December 13, 2004, 11:01

Quote from: "Noble"Was this simply down to running 215's on the front reducing the 30mm front/rear split?

The split on pre 03 cars is 20mm front/rear.

Anonymous · December 13, 2004, 11:06

Quote from: "Bongo"The split on pre 03 cars is 20mm front/rear.

s:oops: :oops: s:oops: Sorry, my bad.

Jap GT300: What do you think of the handling and grip using 225/245's? Any problems with fitment?

Tem · December 13, 2004, 11:18

Quote from: "Jap GT300"I am running 245/45/17 in the rear and 225/45/17 in the front

With the widebodykit, right? s8)

s8)
(probably worth mentioning, before someone thinks they will work with the stock body)

Jap GT300 · December 13, 2004, 15:49

Quote from: "Tem"With the widebodykit, right? s8) s8)
(probably worth mentioning, before someone thinks they will work with the stock body)

Doh... Right.

From a chassis perspective it is still the same though. Handling is not compromised and it sticks to the ground like glue.

I have to say that it is also helped with front/Rear member braces, front/rear strut braces, antiflex plate and Tein HA's.

I wouldn't advise going 245 on stock wheels if that is what you were thinking. This had been done on Kerries 2' but it didn't make a difference, the car was very tail happy (not that it was a bad thing s:wink: :wink: s:wink: ).

Anonymous · December 13, 2004, 23:14

i have 235's on the rears with 17".
you have to get the balance with tyre pressures correct otherwise you tend to slide about abit, but thats the same with any tyre setup.
the car feels a lot more stable (in the wet especially) but again i have the front strutt brace and the chassis plate fitted so that helps alot.

juansolo · December 14, 2004, 06:43

Quote from: "Noble"How did the handling suffer - I'm interested to know how grip improved yet handling suffered? Was this simply down to running 215's on the front reducing the 30mm front/rear split?

Tyre myths:

1/ Increasing the size of your tyre does not necessarily increase grip. There is an optimal contact patch size for any given car. Go beyond this and you can actually have less grip, especially in the wet as you're spreading the load over a larger area. A lot of it is also down to the weight of the car. Bigger tyres are harder to get up to temperature and therefore will be less effective than smaller tyres that move around a bit more but warm up easier. There's a lot to it all to be honest.

2/ Bigger wheels = better handling. Not true. The whole big wheels thing comes from touring and GT cars. The reason they fit them is to accomodate massive brakes, that's it. When they can use carbon brakes like on formula cars the wheels are generally smaller and tyrewalls thicker. Mainly this is down to unsprung weight which has a direct effect on handling. It's far easier to make a light tyre than it is a light wheel. The bigger the wheel, the heavier it is.

Decreasing the tyre wall will mean that the suspension will also have to work harder and will almost always result in a harsher ride in a road car. Again there will be an optimal size. Too much tyre wall will result in excessive roll, too little will give a nasty ride. Usually, manufactuers get this pretty close to right maybe erring on the side of a more compliant ride. Although lately they're all fitting mahoosive wheels to appeal to the big wheel brigade. Sure they look good, but they're likely to be doing you no favours ride wise.

Tem · December 14, 2004, 08:56

Quote from: "juansolo"Bigger wheels = better handling. Not true. The whole big wheels thing comes from touring and GT cars. The reason they fit them is to accomodate massive brakes, that's it.

WRC cars are great example of this. They need big brakes on tarmac and they have biggish wheels on tarmac. But on gravel(/mud/snow/ice) there's no need for big brakes, cause there's not enough grip to make any use of them -> they have smaller brakes and wheels on gravel.