tyre pressure's for drag's

[lyonsy]

just curious what tyre pressure's to run with the standerd 17in sp rubber on the xr8's for drag racing i wss thinking 25psi sound about right?

[FreddyDUZ747]

Id be looking at 20psi max.

[NET351]

I'd be very cautious of running too low a pressure in a low profile such as that. You could damage the sidewall and wreck the tyre completely. Average normal pressure is 40psi so personally I would start at about 35 and work from there. In one of my own cars with 245/60/14 tyres I found about 28psi worked OK but have heard of people running down to low 20s. But that's in a higher profile.

[Quadcams]

Not god running a street tyre lower than about 30psi as any lower it will affect the foot print of the tyre and traction will be reduced.

[falcon_6]

Originally Posted by Quadcams

Not god running a street tyre lower than about 30psi as any lower it will affect the foot print of the tyre and traction will be reduced.

Not really.
I had to drop my 245/40/18 down to 18psi to achieve my 11.91 pass.

[lyonsy]

thanks for that, the tyre's are pretty shot so ill try a few pressure's.

[Tucool]

Originally Posted by Quadcams

Not god running a street tyre lower than about 30psi as any lower it will affect the foot print of the tyre and traction will be reduced.

Absolutely TRUE...no doubt what so ever.....proven time and time again.

[Quadcams]

Originally Posted by falcon_6

Not really.
I had to drop my 245/40/18 down to 18psi to achieve my 11.91 pass.

You will proberly find your driving was the main contributor to the 11.9 pass not the low tyre pressures, drop a street tyre that low and they cup in the middle and only the outside edges have good contact to the ground, not to mention destroying the tyre in the process.
Look at it this way, drive on the street with too low pressures and you will wear the outside edges of the tyre, run pressures too high, the opposite wear the middle of the tyre, run them at correct pressure even wear, using all of the tyre, therefor maximum traction out of your tyre.

[falcon_6]

Originally Posted by Tucool

Absolutely TRUE...no doubt what so ever.....proven time and time again.

No point in adding comments because people respond with sarcastic bull!!!!

[falcon_6]

Originally Posted by Quadcams

You will proberly find your driving was the main contributor to the 11.9 pass not the low tyre pressures, drop a street tyre that low and they cup in the middle and only the outside edges have good contact to the ground, not to mention destroying the tyre in the process.
Look at it this way, drive on the street with too low pressures and you will wear the outside edges of the tyre, run pressures too high, the opposite wear the middle of the tyre, run them at correct pressure even wear, using all of the tyre, therefor maximum traction out of your tyre.

These are my experiences and not others but trial and error is the go when trying to go faster and by dropping the pressures which I did.
I have done over 30 passes on street tyres and always lowered my pressures.
I also have MT streets which I start at 20psi and have been as low as 15psi.
Running 15psi I managed a 11.21 with MTs.

[Tucool]

Originally Posted by falcon_6

These are my experiences and not others but trial and error is the go when trying to go faster and by dropping the pressures which I did.
I have done over 30 passes on street tyres and always lowered my pressures.
I also have MT streets which I start at 20psi and have been as low as 15psi.
Running 15psi I managed a 11.21 with MTs.

MT advises not to run below 16psi because it is unsafe... a quick time maybe
but the finish line could be a coffin... not sarcastic just an ounce of prevention could save lives.