Tyre Pressure

Ian Anderson

Lifetime Supporter
What sort of tyre pressure do people use for their GT40s?

I had been running on OLD BF Goodrich 15 inch tyres and ran at 22 - 23 psi front and 25-26 psi rear - but these tyres were really hard. Checked date stamp and they were made in 1988!

I just replaced with Kumho tyres and at 28 psi front and 30psi rear the tyres still look fairly soft. (But what a lot less road noise!)

So I'm looking for pointers for pressures for a car primarily based on the road at legal? road speeds

Ian
 

Mark Charlton

GT40s Supporter
Lifetime Supporter
I'm using 26 front 28 rear, but I am not aware of any rule for the pressures. Start with something you think makes sense and adjust if you feel the tyres are too hard or squishy.

Mark
 

Julian

Lifetime Supporter
For a car weighing 2200 - 2600 lbs Hoosiers recommendation is 27-31 psi, so I think you are in the right range, as Mark says where you end up in that range is down to personal preference.
 

Ian Anderson

Lifetime Supporter
Thanks people

I did some airfield runs yesterday and loads more grip

Over some bumps seem to get a tail end move so presumably need to have the alignment checked and set properly on the rear to try and stop this bump steer type movement

Not enough distance travelled to see if edges or middle of tread wearing more

Ian
 
Thanks people

I did some airfield runs yesterday and loads more grip

Over some bumps seem to get a tail end move so presumably need to have the alignment checked and set properly on the rear to try and stop this bump steer type movement

Not enough distance travelled to see if edges or middle of tread wearing more

Ian

Hi Ian,
Thanks for raising this issue.
Your post made me return to experimenting with my pressures.
I increased them to 27/31 and this has improved (on first impressions)the Handling & Ride (significantly) and Road holding (marginally) so not a bad result!
Cheers
Paul
 
You can also try an IR thermometer across the tread from inside to outside - after some spirited track work it should be a nice progression from lowest temp to highest temp moving from inside edge to outside edge. If you have a hot spot in the middle with lower temps on the outside edge then it's worth monkeying with the pressure a little to see if you can moderate that. Just my $.02.
 
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