Too much Oversteer

[JBT]

JBT has said many times before, a major factor in him running the pressure he does is because it's too harsh at 36+ PSI.

Don't mis-quote me Boags. It was one factor and only applicable to the NA - keeping the car on it's intended path was the main one.

I've tried up to 38psi on the NC on both Michelin PP2, Bridgestones RE050A and Yokohama povo Advans. Can't pick much in ride change but the car starts to become skittish at high pressure and, with the Yokos, a greased pig.

[Boags]

Sorry JBT; it must have been another forumite. But I remember having the "tyres aren't there for ride-comfort" discussion before.

[AJ]

I think I might keep to myself with this one

[bensale]

Some really interesting thoughts guys. Correct pressures do vary massivly depending on car, tyre and the circumstances in which you use your car. Personally I find that around the suburbs 38-40 psi (stone cold) feels the best on my na6 with 16' nb wheels & bridgestone tyres. However, on some of the mountain roads with a lot of corregation it can feel a bit skittish, although hardly like a 'greased pig.' I guess it really comes down to (as Ted said) the technical factors as well as driving style and preferances.

The figures regarding aquaplaning come from the DECA handbook.

Getting back to the 'too much oversteer' topic I've found tyre pressures to greatly vary the characteristics of the car perhaps you could have a play with them.

[manga_blue]

Sorry JBT; it must have been another forumite. But I remember having the "tyres aren't there for ride-comfort" discussion before.

Boags, my car was running 28 psi on street tyres when you drove it. I'd tried everyting from 24 to 40. 28 cold was the sweet spot for street, anything over 32 meant lost grip. 30 cold was it for lap times on the same tyres. I usually add 4psi for wet to combat aquaplaning.

[Adam_NAclubman]

Boags, I got Yoko A539's when I got my Buddyclubs and a) they sucked with anything over about 33psi, skittish and nervous feeling, and b) They transition very quickly from lots of grip to nothing, and when you're travelling at speed that can kind of suck.

Bridgestone RE540 and RE55S semis on my DR30 also had a pretty narrow range of pressures that they liked, but they were a bit better in the transition between mega-grip and slideways, but I hardly think we're going to reccomend someone buy semi-slicks for a daily driver.

The cheap and cheerful RE88's and RE592's I run on my 14's are good to drive on, wider transition from grip to nothing and aswell as having a bit more feel for when they are running out of grip they also screech like banshees to let you know.

MX5 is all about feel, and I'd rather have more warning that grip is running out even if it means I cant take a corner 15kmh faster, especially on a short wheelbase car like the MX5.

The whole point of me mentioning it in the first place however was to highlight that going straight to new sticky rubber to stop the car oversteering was a bit of a waste of money when playing with tyre pressures and seeing what works with your car and tyres could fix it for free. Especially if you get new sticky tyres, run the wrong pressures in them and then still have problems.

Braking distances and how hard you can brake, yeah sticky tyres win that, but he wasnt complaining about the braking with his current tyres. I do 200km a day around town in a non-abs Echo on 185 RE592's (previously had RE88's aswell) doing deliveries though and have never had a problem with stopping in a hurry, or keeping SS Commodores honest down Belair Road because I know how hard I can push those tyres.


If you're worried about aquaplaning, I dunno, maybe you could drive slower if you think there is going to be standing water... Or run narrower tyres

[Boags]

That's more like it, Adam.