tyre pressures
- Thread starter daveb
- Start date
Howard Jones
Supporter
Rule of thumb to start out with. 1% of the weight as expressed in PSI.
2500 pound car = 25 PSI. The best figure can only be determined by trial.
20 Mins of track work increased my tire pressures by 4 psi from 24F to 28F and 26R rear to 30R with air temp at about 80 degrees and full sun.
Oh and I'm not as fast as Bud.
2500 pound car = 25 PSI. The best figure can only be determined by trial.
20 Mins of track work increased my tire pressures by 4 psi from 24F to 28F and 26R rear to 30R with air temp at about 80 degrees and full sun.
Oh and I'm not as fast as Bud.
Howard,
Your "rule of thumb" sounds more like a guess. By your logic my 4,000+ pound Lincoln should have 40 PSI. In fact, most tires take about 25 - 32 PSI no matter what the weight of the car is. Best bet is to follow the manuafacturer's recommended setting!
John
/ubbthreads/images/graemlins/driving.gif
Your "rule of thumb" sounds more like a guess. By your logic my 4,000+ pound Lincoln should have 40 PSI. In fact, most tires take about 25 - 32 PSI no matter what the weight of the car is. Best bet is to follow the manuafacturer's recommended setting!
John
/ubbthreads/images/graemlins/driving.gif
My Touareg V8 with 275/45x19 performance tires requires 39F 41R light load. Over a number of performance cars with summer performance tires the lowest Psi I have ever run was 30 for street use only, when auto crossing or track days it will change to the plus side depending on the car and the ratio front to rear will change depending on the balance I'm looking for.
Peter
Peter
Howard Jones
Supporter
Hey! Rule of thumb means if you have no clue, start here. Then figure out what works best. A 4000 pound car would be fine on 40 psi just as a 3000 pound car would be OK on 30 psi. There is of course a lower limit! Anybody who thought that a 1200 pound super 7 lightweight should run 12 psi isn't paying attention.
You could put 35 psi into any Mustang ever built and drive it forever and be just fine. Would that be the "best" ? Hell I don't know! Nobody does! The question has no answer except Ron's. I was trying to offer a place to begin other than read the tire manufacturers paperwork and pump it up like it says.
If you start out on cold tires in a GT40 with 25 psi in them you will end up at about 27-28. This is a safe pressure to go for a nice easy Sunday morning drive and for the record not at 150mph either. I could go into what it takes to set up tire pressures at the track, all that stuff about getting out a tire temp gauge and start recording tire temps across the footprint. Screw with camber etc. until all were as close to equal as you could get. Then start fooling with pressure and lap times to finish it off. All the while constantly checking pressures to be safe.
Anyway put 30 psi in them. That's what I should have said in the first place.
You could put 35 psi into any Mustang ever built and drive it forever and be just fine. Would that be the "best" ? Hell I don't know! Nobody does! The question has no answer except Ron's. I was trying to offer a place to begin other than read the tire manufacturers paperwork and pump it up like it says.
If you start out on cold tires in a GT40 with 25 psi in them you will end up at about 27-28. This is a safe pressure to go for a nice easy Sunday morning drive and for the record not at 150mph either. I could go into what it takes to set up tire pressures at the track, all that stuff about getting out a tire temp gauge and start recording tire temps across the footprint. Screw with camber etc. until all were as close to equal as you could get. Then start fooling with pressure and lap times to finish it off. All the while constantly checking pressures to be safe.
Anyway put 30 psi in them. That's what I should have said in the first place.
Hi John,
Unfortunately the GTD manufacturers manual states 21/23 but that seems to be overtaken by events!?
Cheers /ubbthreads/images/graemlins/confused.gif
Unfortunately the GTD manufacturers manual states 21/23 but that seems to be overtaken by events!?
Cheers /ubbthreads/images/graemlins/confused.gif
