Track Tire Pressure Question

[Ross]

Here's a question for those of you who have some track experience. I know that a lot of guys lower their rear tire pressure significantly at the track to get better hook up at the start. I understand that part of the equation OK.
My question is, won't the lower pressure create more friction on the track surface all the way down the quarter, thereby slowing the car down somewhat? Is it a trade off? Better traction up front even though it slows you down a little down the stretch?
Just wondering, not planning on racing anytime soon, except maybe for rice boys on the street.

[crowdog]

I lower tire pressure to 21 psi and it make a dramatic difference. You will lower 60' and 330' times and be much more consistant. I make anywere from 160 to 180 passes a year,depending on how may rounds I make and these pressures have served me well.

[MikesMerc]

You hit the nail on the head already when you said "Is it a trade off? Better traction up front even though it slows you down a little down the stretch?"

This is exactly the case. The increased rolling resistance from having less pressure is more than offeset by the gains on the launch.

[Ross]

That's kind of what I figured. So, there is no "perfect" tire pressure for the track. Higher pressure means more speed down the stretch, but less traction up front. Lower pressure means just the opposite. Thanks for the answers, guys.

[Dragcity]

Don't forget about ~ Centrifugal Force. When those rears start spinning, the tire wants the center to be as far away from the rim as is physically possible. They will also gain pressure as the heat rises. The "trade off" is lower than you might first think.

In other words, keep it as low as the bead will tollerate. If you're not tubed and screwed, I wouldn't go below 20 PSI. Get a good launch, all else will follow. If HP is too low, you'll bog out either at launch, or when you finally hook.

Drag racing is a tough run....But Real Fun!

[SergntMac]

Can't disagree with the fine advice posted here already, just adding my own .02C.

I've had good luck with drag radials at 18-20 PSI, and street tires 24-26 PSI, you really need to make a few passes to see what works on your particular car. Be aware that suspension "loose-ness" plays a large roll in this too.

Don't forget the front tires, they should be pumped to the max rating, and for the same reasons, rolling resistance.

Every little trick adds something to the slowest part of the pass, the launch.

[ctrlraven]

I lowered my oem tires to 28psi and what a difference on my r/t and 60' time. Next time I run I may lower to 26psi just to see if their is any difference. Just do a nice quick burnout to heat up and clean the tires off, make sure you have traction control off (if you have it), preload the torque convertor to 1800-2200rpm and when that 3rd yellow shines bright, mash the hell out of the GO pedal. I asked the same question a month ago or so and went from 14.8-14.9's to 14.6-14.7's just by preloading the t/c and lowering the tire psi and I only had a K&N drop-in filter and rear exhaust delete from h-pipe back.