How do I figure out tire rollout?Not at all.. they are interested in ET ... the questions I am asking will change your MPH ... which is what you were asking about .. your on the right track to finding some MPH
Fastest TTA Thread (2014)
- Thread starter TT/Ameasap
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Flexible tape roll... around the tire in the center .. keep in mind the pressure of the tire when measuring !!!!
That's how I did it, and came up with the 7' number.... Just did it really quick.
Easy big guy. Remember my initial number I said approximate? I said tonight I can get exact.
Hehehe.. I am going easy ... just wanted to bring to light there is a huge difference in 4 inches of rollout is all ..
and that DETAILS make or break a car in performance ...
After you questioned how I got that number I thought you were asking for something else. I'm anxious to see also what the difference in roll out will be from a 26" tire to a 28" tall
TT/Ameasap
The White Blur
- Joined
- Jan 31, 2002
This info is posted on the tire manufactures websites. If its a DR then the number will be really close. If its a bias ply (slick) you will have to measure rollout. This number can be off from one tire to the next by 2+ inches. That is why your supposed to buy a matched set of slicks. However, you can make the difference if the pair are just an inch or less within each other by over-inflating the smaller tire.
The one link I posted has info supporting what you're saying. I know you checked your tires recently, and noticed a big difference didn't you?
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TT/Ameasap
The White Blur
- Joined
- Jan 31, 2002
My rollout was 1'' and I got it to perfectly even out after a couple tries.
What pressure difference did it take to get it even?
TT/Ameasap
The White Blur
- Joined
- Jan 31, 2002
I can remember exact pressure. Somewhere in the neighborhood of 35-40 for 20 minutes or so. I had to do it a couple times. I also had the wheels off the car when I did this. I measured the rollout on the floor.
TT/Ameasap
The White Blur
- Joined
- Jan 31, 2002
No. It stretches the rubber.
You're gonna start talking dirty now?
TT/Ameasap
The White Blur
- Joined
- Jan 31, 2002
Dont make me bring up the shaft polishing thread!
Touche!Dont make me bring up the shaft polishing thread!
Both tires are exactly 82"!
Okey .. so now let me give you an example going from a 83 to 87 picked up just over 4mph .. some came in the first 660 feet... some came in on the top half .. nothing other than tire was changed.
on another note.. going TOO FAR on the rollout .. and you will not see any gains and may actually lose...
since you are running a stock motor you don't have the luxury of extending the upper range... and another thing you should be conscious of is datalogging your runs and seeing where your car spends its time during the 1/4 mile run ... THIS TIP is where guys can find 2-3 mph right off the top ...
The reason I asked about the rollout is that ALOT of the times ( depending on what tire you are using ) the diameter is defined as a certain number but when you measure rollout .. its way off.