Reader Question: Tire Prep
Written by T.C. on June 26th, 2008I got a great set of questions from reader Kenny and thought I’d write a quick post in response. Kenny asks:
How long does it take for the tire specialist to change the air pressure? Are there tires set up with a quarter or a half-pound up and a quarter or a half-pound down so you can quickly grab one?
Does NASCAR’s Rule Book allow you to scuff the tires without putting them on a car? That is, could you set up some sort of axle turning which you could apply some pressure and perhaps either a sander or some buffer?
Since I know tire performance doesn’t reach its peak until a few laps are done so the tires get scuffed and warmed up, could they be warmed up in advance, so the tires are ready to deliver the right grip more quickly?
First, tire specialists can change the pressures very quickly. During the race, the tires are laid out in numbered sets and are put on the car according to the crew chief’s strategy. The tire specialist will monitor the pressures in each set throughout the race to keep them close to where they would need to be for a pit stop. After the crew chief and the driver have discussed handling issues, the crew chief will make the decision right before a pit stop about what to set the pressures at. The tire specialist will then run around with his pressure gauge and make any last minute changes then.
From my understanding, the only way to scuff tires is to put them on the car and run around on them during practice sessions. Goodyear doesn’t issue tires before a race, so there is no way to do this at the shop, and the rules won’t permit it at the track. But its not uncommon for teams to get help from other teams scuffing tires during practice sessions.
NASCAR does not allow any sort of tire warmers and they don’t allow the tires to be soaked in any chemicals. You will see tire specialists keep their tires under shaded covers depending on the heat, but that is the only allowed method to control tire temperature. That is why you’ll see drivers weaving back and forth under caution. It cleans the tire’s surface and gets a little heat in them.
These were great questions, so thanks Kenny! Something to also keep in mind in terms of the rules, is that if its legal and it will give them better performance, all the teams will be doing it.
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Comments: 4
Comments
Comment from Pembrook Feeney
Time: June 27, 2008, 9:43 am
And what about the advantages of using nitrogen, etc instead of “air”?
Comment from admin
Time: June 27, 2008, 11:53 am
Teams use Nitrogen in the tires because it has less moisture content then regular air, and is less apt to pressure changes because of temperature.
Comment from Pembrook Feeney
Time: June 28, 2008, 3:52 am
So with Nitrogen, you are saying the pressure characteristics are much more controllable and one is more accurately able to control tire pressure in smaller increments ( 1/4 lb, 1/2 lb).
Are there any other chemicals used? We know that dipping the tires is illegal - Many though J Gordon was doing that a few years back. What exactly would be the effect and the advantage of dipping the tires - and what the heck would they be dipped in anyway?
Mercedes Benz in its passenger cars recommends Nitrogen btw.
Comment from admin
Time: June 30, 2008, 12:58 pm
There are absolutely no chemicals allowed in terms of treating tires (called dipping or soaking). NASCAR has a very strict policy when it comes to tires; its just something you don’t do.
Soaking the tires softens the rubber and allows for better grip. Normally though, the grip doesn’t last for a sustained period and the tires wear faster.
There are many commercial products available for tire soaking and many people make their own mixes. I’ve heard of tires being dipped in everything from acetone to diesel fuel.
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