tyre pressure

Anonymous · March 21, 2004, 21:34

I know that this thread has been posted before, but I found something that I want to share with you, guys.
As everybody knows this car is very sensible to tyre pressure, and everybody knows that the standard choice is a good choice.

But I have always had a bad problem with the front tyres. With the 26 psi, I get a good balance, but if I drive fast in a mountain road, the tyrewalls start to bend, and that stops all the fun.

If I put more pressure, 30 psi, for example, I have less tyrewall bend, but that's a bad choice, because the front of the car starts "bouncing" all over the place.

I have mounted yellow konis and TTEsprings, and I have found that if I put the regulation of the front shocks almost to maximum, I stop the "bouncing", get a nice handling, certainly faster, without almost no tyrewall bend. Now I use 30 psi in the front, 33 on the rear, with very good results. s:wink: :wink: s:wink:

mph · March 21, 2004, 21:59

As much as anything, tyre pressure is dependent upon what make you're using too.

For example, the Eagle F1s I tried had such soft sidewalls that I was upto their maximum 48psi (warm) (IIRC) before I could curb them from rolling over. S03s seemed happy at 32psi (warm) (note they were 205 fronts..), while my A539s had no trouble at 26psi (*hot*!) on track with the sidewall not rolling over unduly.

Anonymous · March 22, 2004, 08:25

i think it depends on ur driving-like and the mods u have. i run 26f/32r on my yokohama a539 tyres.

Anonymous · March 22, 2004, 18:17

I had as gift 4 Yoko Advan slick tyre 195/55/15 and i run on the track. I got my best laps with 24.5 Front and 29.0 PSI rear ( cold) i.e. Same times i've obtained with Bridgestone Potenza 540 S ( a racing tyre approved for street use) 205/50/15. To minimize oversteer, i have settled my Konis on max rebound in front and 3/4 turn from max on the rear and TTE swaybars on the middle. I took off 24 kg. from the rear end of car also, with a new aftermarket header,cat and muffler. More, if the tyres slide air temps go on; i think it's helpful to control tyres pressure when are hot after a hard run, also. s:wink: :wink: s:wink:

Anonymous · March 24, 2004, 00:37

Sure, you are right, it depends on the tyres and on the set up, and this post guys, was not meant for you, that know a lot more than me, but for the ones that know even less than me, if there is anyone s:roll: :roll: s:roll:

And the thing that I didn't know and that i found out, and I think can be useful to others is:

Stock tyres, and most of the range of the tyres for the Mr2, except racing/street tyres, have soft tyre walls (for comfort). I have tried the stock yokos and the dunlop sp 9000, and that's the case,( and mph says the same about the eagles f1).

With stock suspension you cannot make those tyres walls more rigid, putting more pressure, because with much more than 26 in the front, the front shocks have not the ability or power to stop the front of the car from bouncing up and down.

But if you change the front shocks for some good regulable shocks (for instance, the yellow konis) and set the shocks hard, you can put much more pressure in the tyres, improving tyre walls rigidness, because now they are able to control the front of the car.

Now you have a lot more possibilities, and if you don't have some expensive racing/street tyres, that are much more rigid and can run with 26 psi without tyre wall bend (but with a less confortable ride), you can have stiffer tyre walls in your stock tyres, without degrading performance (in my opinion with improved performance, but that has to do with the speed you take corners), and with little difference in comfort.

markiii · March 24, 2004, 00:56

or just buy s03 which have a stiff sidewall.

juansolo · March 24, 2004, 07:51

'03+ =Neova's

24-25 front, 30-32 rear. ish and oversteer-tastic.

More sensible people may want a little less at the back.

Anonymous · March 24, 2004, 11:00

Quote from: "markiii"or just buy s03 which have a stiff sidewall.

I have tried to get those for a 2003, but the sizes available make them illegal in Portugal, and also in Germany (it's just a small difference, but the law is the law). You can use them legally in GB?

markiii · March 24, 2004, 13:39

you mean you can't legally use tyres of different sizes to stock over there?

Anonymous · March 24, 2004, 14:15

Yes, but only within certain limits.
With the S03 it has to do with the diameter of the tyre that is out of those limits ( here and in Germany ). s:cry: :cry: s:cry:

markiii · March 24, 2004, 14:18

03 rears available for 203 would be 225/45/16 I take it this is out of spec?

Anonymous · March 24, 2004, 21:50

I think so, but I am not sure s:oops: :oops: s:oops:
I was in Germany, at Lampka, mounting some stuff in my car, when Andy (one of the main man there) found that the interior of my front tyres was gone. It was snowing, and I needed new tyres to get home safely. I asked Andy to get me the S03s. He went for the catalogue, made some calculations and said there were no SO3s tyres for the 2003, he explained to me why, and said they didn't have the right measures to be legal. He said to me he had tried pretty much everything that was suitable for the MR2 (we were not talking about race tyres) and that the ones he liked best were the Dunlop sp9000, and that's why I have mounted them on my car...and I don't regret it:wink: