Drag Racing Tech - What does all DRIVE TIRES MUST BE MATCHED TO BE WITHIN 1/2'' ROLL OUT.

I saw this when getting ready to order some ET streets, what does this mean and how do you check for it?

if I order a set of drag tires together will they already be matched for this

You need to measure the circumference.

Just because you order the same size tire doesn't mean they will match. Whereever you order them from I would ask them to measure them to make sure you are getting a close match set. I have seen tires over 1" difference.

Ken

Rollout is circumference
Bias ply tires can vary from tire to tire. Like said above, ask them to measure each tire before you buy

Absolutely measure them yourself. Don't rely on someone else. If you don't get two that are close enough, the car won't drive straight because one tire will be taller than the other. I usually take a piece of string, wrap it around the tire in the center of the tread, and measure the length. Do the same on both tires and if they're within 1/2" of each other, you're good to go.

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Very very important if you have big power.
I carry the front wheels pretty good on my car and as mentioned,
you will drive right or left if the rollout is way off.
Definitely not much fun when you can't steer and heading towards the wall!!

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this is what I thought it ment, thanks for the info now I know how to properly setup my drag kit

Also if you have a spool, it will pull to one side a lot driving around on the street.

There's a way to fix it though, bias ply tires will stretch out some. When you get the tires mount them up, air them to 15 lbs, and measure with a string the rollout. If one is more then 1/2 an inch smaller then the other, inflate the smaller tire to about 25 psi and leave it that way for an hour or so, then deflate back to 15 lbs, and check again. Putting the tire in the sun can also help while aired up... the tire will stretch some.

By doing this you usually can get another 1/2 to 3/4 of an inch out of a tire if it's off. As long as the tires are within 1/2 an inch of each other you should be fine, unless you're talking about a 2000 hp car, in that case they probably need to be about perfect.

The last set if et drag's I bought were off about 3/4 of an inch, and I was able to stretch the smaller one by doing the above procedure about 5/8 of an inch, they were less then 1/4 of an inch different afterwards. The hoosier's I just bought were almost perfect right off the bat, about 1/8th of an inch diffrence between the 2, and they're a bigger tire on top of it.