GD tyre pressures

[maxGD059]

What pressures do you fellow GD'ers run? My GD is jag based with a rover block. During a post winter blast down the rather bumpy Fosse Way south of Leicester, I seemed to be bouncing all over the place. Perhaps I was going much faster since fitting a performance cam. (!) or is 20psi just too much for 55 profile tyres on 16 inch rims?

[wilf]

There was a thread about this a while back - try a search on "pressure(s)", see what comes up.

You can't be too far from me - I'm in Mountsorrel - we should meet up some time.

Wilf

[russell_ram]

I run Avon ZZ1 225/55/16 front, 255/50/16 rear. After a bit of playing around with the pressures and still not being happy, I phoned the Avon motorsport tech helpline and chatted to a very helpful bloke (cant remember his name) who took all car details, corner weights etc and promised to phone me back after consulting his loading tables etc. He duely did ring back (a suprise but I did tell you he was helpful) and said that from tyre loading and speed rating etc the correct pressure for max tyre performance was only 12psi. He was very suprised by this as this is the same tyre combination fitted as OE on 'real' AC CRS etc and they recommend 30psi all round, but they vehicle manufactures do not necessarily go by tyre manufacturers recommendations (we certainly dont).

Anyway, he was happy that there would be no roll off or deflation issues at such a low pressure. However, the steering was very heavy, not unsurprisingly I guess, and the car felt a bit wallowy. I have since compromised a bit and now run 16 all round, but when you roll gently over dust it's definately not using all the tread width.

I would think 20 psi is a bit too high, let them down a bit and see what it feels like.

Russell

[maxGD059]

Thanks for the advice guys. Dropping the pressures to 17psi has helped, but after chatting with Andy Burrows at Stoneleigh, he reckons I've not got the suspension settings quite right. Like the good chap that he is, he says he'll sort it when the dust settles after the GD Open Day on 1/6/2002