Tire Question

[Annie Clope]

I was wondering why some teams had a white line on the outside and a triangle on the rear tires. The only thing I could come up with was maybe it was to measure tire growth. Does anyone know why the teams mark the tires like this?

Thanks,
Annie

Here is an example, it is small but you can kinda see what I am talking about.

 

[Just Paul]

The triangle is to help see how fast the tire is turning on the video, and the white line around the tire is to see how the tire squats and deforms on launch.

 

[clwill]

With Racepak's software (which most teams use) you can tie a video to the data, and go frame by frame, looking at the rotation and deformation of the tire and tie that into the exact data you're getting from the data recorder -- such as air/fuel mixture, exhaust gas temp, driveline speed, engine rpm (and therefore clutch slip), etc., etc. You can see exactly what caused the wheel spin. Very cool...