Molds

My car seems to understeer like mad at the moment. On my way home from work today I was thinking about it. I reckon I havent checked my tyre pressure in 6 months! Do you think it is down to that or is it just that I am used to the handling and expect too much of it?

Standard UK car with 16" wheels running Continental 205/50/R16 87W tyres.

TBH I dont even know what they should be inflated to. The label inside the drivers door says 205/55(note:mine are 50)/R16 87V is FR:33psi RR:28psi on light load. The user manual says slightly different. A lot of people on here seem to go 32psi all round.

Help!

Cheers

Matt

PS I didnt check the inflation today as the tyres would have been too hot.

S55 HOT

Poor tyre pressures won't help - but neither will having Continental tyres

Get yourself some Goodyear F1's, 32 psi front - 28 rear, get your geometry adjusted to the maximum negative camber that is even both sides on the front & toe in 1mm front & rear.

You won't believe the difference !

It's really not worth having a Scoob if you're going to skimp on the tyres !

Molds

Pity the Conti's are not any good. The guy I bought my car from had a flat 1 week before I bought it. He swapped all 4 which I thought was good as it was one less thing to worry about. I only do about 5000 miles per year so they will have to stay on for a bit longer as I only had the car kast July!

Is 32/28 "normal" for that tyre size then?

As you can see from my questions I am a Muppet with regard the rubber. As for "geometry adjusted to the maximum negative camber that is even both sides on the front & toe in 1mm front & rear." Hmmm, perhaps I need to print this and take it to the tyre shop with me?!

Cheers

M

S55 HOT

Sorry I actually meant 32/30 - don't know why I put 28 !

The geometry settings will mean something to anywhere that does allignment. They will probably tell you that it will increase tyre wear as it angles the front wheels slightly so that the bottom is further out than the top, so theoretically the inside edges will wear out quicker. However, I still wear out the outside edges first anyhow !

Here's some more information - if you're new to Scoobys then you should read the lot

Al

911

I hill climb my STi on 205 x 16 x 50's, Toyo's (of course)and find I need 35/35 to kill some understeer and to avoid turning on the sidewalls (not kidding). Go to Whiteline.com.au for all the real advice you need!
Agree with all the above, and remember it is a personal thing, driving style that is.
Graham

JIM THEO

Usually more pressure front - less by 4-5psi rear helps to eliminate understeer but can't understand why there are so different factory recommendations through different countries.
I used to have 34-35psi front with 29-30psi rear, max neg camber front/zero toe - factory camber rear (-1,10) and less than 1mm per side toe out.
The above setup gives you more oversteer in every case but is much better for B roads!
JIM

russell hayward

If you have run your tyres underflated for prolonged periods this may well have rendered them DANGEROUS !

Molds

After reading the replies I tootled off down the garage whilst the tyres were cold and checked the pressure.

A mixture of anything from 25psi to 28-29psi all round.

I banged in 32 front and 30 rear and off I went.

Car feels like it used to now. Of course it still understeers if pushed but has given me confidence back in its abilities.

Goes to show how much these things can affect your ride and why thoughtful regular maintenance isnt just for saftey but keeps you looking like this

Cheers for all the replies

Matt

Kempo

Matt

Get yourself a tyre inflator (runs off ciggy lighter) and a pressure gauge from halfords. You won't believe how much more likely you are to check the tyres when you don't have to trudge down to the (usually inaccurate) petrol station machines.

I had to top my tyres up by 10% this weekend and the difference was amazing - bye bye understeer.

Cheers
Paul

P1Fanatic

I used to run my Toyos at 32psi but someone on here said they perform better at 35 so I pumped mine up and they are a lot better now. Think its cos Toyos have quit weak sidewalls.

Simon.

patGT

The tyre pressures here and in the FAQ seem to differ quite a lot from what is recommended on Continental Europe. In my car's handbook (MY99), there are figures recommended as follows: 2.7 bar (39 PSI) front/2.5 bar (36 PSI) rear.

So far, I stick with it and I experienced it as very reasonnable settings. However even with that, there is significant front tyre shoulder wear on hard cornering. Therefore, I even increased the pressure somewhat for my Ring trips - and found it very suitable.
I apologise in advance but I could hardly imagine 32/30 to be enough pressure, excessive tyre shoulder wear and understeer is what I would expect.

Has anybody an idea where these different recommendations for the same car come from? The air should basically be the same in both Great Britain and Continental Europe, isn't it? ;-)
Or does it even have something to do with geometry settings?

Regards,
Patrick




[Edited by patGT - 3/10/2003 5:11:50 PM]