Tyre pressure

[Pat]

Wondering if anybody can advise on tyre pressure for my setup, tyres are Cooper Cobras:

Front: 235/60/15
Rear: 295/50/15

The car seems a little unsettled under hard acceleration / deceleration.
(Especially when windy)

Blue skies,
Pat

[stevee8]

Will depend partly on your engine weight but you should find 18 - 20 psi front and rear not too far off the mark.
Your concerns may not be tyre related, although it's the easiest thing to experiment with as a start.

[Robin427]

Originally Posted by Pat

The car seems a little unsettled under hard acceleration / deceleration.
(Especially when windy)

Give Andy at GD a ring... he'll tell you why your Dax is handling like that!!

[Purple AK]

Rear Shock settings can give the same feeling in Windy conditions

[Pat]

suggestions welcome
and appreciated

calling GD about a DAX???
worth a try

[Purple AK]

Originally Posted by Robin427

Give Andy at GD a ring... he'll tell you why your Dax is handling like that!!

What has Water Balasting Tractor wheels got to do with a Dax? :finger:

[Dutch Paul]

Originally Posted by Purple AK

What has Water Balasting Tractor wheels got to do with a Dax? :finger:

5 bar farm gate?

It`s the only common link I can see

[RallySnake]

Pat,

The answer to your question is not so easy. What is the width of your rims? My car has 8.5 inch wide front rims and 10 inch rear rims. When I take the car to an autocross where handling is paramount, I like to pump the tires up to 35 pounds all around. If the first run is loose (rear slides too much), I drop the fronts a couple of pounds. If the car is tight (front slides too much), I drop the pressure in the rears. The thing is, with this much pressure, the center of the tire treads wear out quickly, so you don't want to run this way all the time.



For comfortable street use, I use 24 pounds front and 26 in the rears. The tires last a lot longer this way. But, like you say, on a short wheelbase car like the Cobra, the handling gets squirrelly if you start pushing it in the corners.



The very best answer is to buy a tire pyrometer like the racers use. After driving for a while, you measure the temperature in three places on each tire tread (outer edge, center, inner edge). If the center is hotter than the edges, reduce the pressure. If the inner edge and center are hotter than the outer edge, adjust in more positive camber. You get the idea. Most of us never go through this exercise so we never know, for sure, what the best pressures are. We just go by “seat of the pants”.



The other factor is the stiffness of the tire sidewalls. I haven’t run Cooper tires and cannot comment on this. I suspect that these tires are good for cruising, but not stiff enough for serious corner carving. You have the option of pumping them up for better handing, but reduce the life of the tread (in the center).



Paul