Track vs. Street Tires
by Pat Goss
Well you want to take your car to the race track, and you think you’ve got the proper tires, well you might be wrong. And here to give us some pointers Rick Robinson from American High Performance in Lorton, Virginia. Rick, welcome back to Goss’ Garage.
RICK ROBINSON: Thank you Pat.
PAT GOSS: Alright, here we have a typical tire, big, low profile. Good for the track?
RICK ROBINSON: Absolutely not, and these are what you and I see all the time. People come in with these great big wheels, little skinny tires and they want us to mount them. We have a heck of a time mounting them to begin with because this very narrow sidewall on the tire is so still in order to be able to support the weight of the car that it has no flexibility to it whatsoever. Flexibility is important in the performance of the tire when it’s trying to maintain the contact patch grip on the pavement.
PAT GOSS: Alright, and this applies not only to drag racing but if we’re going to do a track day or something like that in road racing as well.
RICK ROBINSON: Absolutely, in drag racing we’ve seen the videos of a drag car launching. The slinks wrinkling up as the torque is applied to the wheel. That flexibility in that tire is what allows that contact patch to maintain its grip on the pavement under that tremendous load. Same thing applies to road racing except it’s side flex, I’m going through the corners, all of this force is being applied to the side of the tire that tire needs to be able to flex in order to maintain its contact patch. If it’s stiff like this thing and hard it’s going to break loose, you’re going to skid.
PAT GOSS: OK, Alright, now tire pressure for drag racing.
RICK ROBINSON: You’re gonna run them pretty low, lower than most people would imagine. 12… 13 pounds of pressure is not unusual at all. And again we’re trying to let the tire be flexible and get a larger contact patch on the pavement.
PAT GOSS: Alright, and finally this particular set-up you have screws going through the wheel.
RICK ROBINSON: Yes, they’re not there to hold the wheel together, they actually hold the tire to the wheel, because under that tremendous load at launch that wheel will actually spin inside the tire if you don’t have them screwed together.
PAT GOSS: Rick thank you, and if you have a question or comment drop me a line right here at MotorWeek.