46callaway
Registered
What is the optimum psi to put in street tires for best launch? Usually I put 40-42 psi in the fronts and leave the rears at 30psi...
PSI for street tires?
- Thread starter 46callaway
- Start date
Don't go too much lower than 28. Most street tires have extremely strong sidewalls and happens at low pressures is that you loose ground contact pressure in the center of your contact patch. There comes a point where you are actually putting less tire on the ground.
Drag radials and slicks have much weaker sidewalls exactly so that does not happen.
Drag radials and slicks have much weaker sidewalls exactly so that does not happen.
Closely examine the tire(s) after each run. Look for the edge of the 'burnout rubber' - there should be a distinct line at the edge of the part of the tire that was spinning in contact with the track. With a properly inflated tire for the street, that edge will be away from the midpoint of the raduised treadblock towards the tread of the tire.
As you lower the tire pressure(say 2 psi each time), you will notice the edge of the burnout advancing towards the sidewall. This gives a wider profile in contact with the track. Depending upon the tire construction, when a drop in pressure does NOT result in wider contact patch - ADD pressure(1-2 psi) to go back one step.
This method also works well for drag radials, but you'd likely want to dump 5-10 psi at the start.
If you record your results you will notice different target pressures for different tracks and weather conditions.
But - if you monitor this closely and examine your timeslips you will likely find a pressure that results in a better sixty foot time that is slightly higher or lower than the pressure determined from the method described. This is due to track conditions and is more noticeable with drag radials than street tires.
As you lower the tire pressure(say 2 psi each time), you will notice the edge of the burnout advancing towards the sidewall. This gives a wider profile in contact with the track. Depending upon the tire construction, when a drop in pressure does NOT result in wider contact patch - ADD pressure(1-2 psi) to go back one step.
This method also works well for drag radials, but you'd likely want to dump 5-10 psi at the start.
If you record your results you will notice different target pressures for different tracks and weather conditions.
But - if you monitor this closely and examine your timeslips you will likely find a pressure that results in a better sixty foot time that is slightly higher or lower than the pressure determined from the method described. This is due to track conditions and is more noticeable with drag radials than street tires.
