View Full Version : Auto X last weekend

04-25-2006, 08:29 AM
So I was at an Auto X this past weekend and am looking over my G-tech readouts and lookin over my videos a little. My G-tech shows me pulling .9G lateral and .05 longitudinal. So does that mean I pulled .95Gs total or is the total number different or does it even matter?

The reason I ask is I was running on my Penske Kmart junk tires that were sitting in my garage for 6 years and I was just surprised that they held up that well and that I turned the times I did with them.

Damn True
04-25-2006, 08:42 AM
The .5 longitudinal is recorded under acceleration or braking and the .9 lateral during cornering. Two different axis of motion.

The .9 was likely a transient spike. Different from a skid-pad measurement which is a measure of sustained cornering load.

04-25-2006, 07:32 PM
Ok so the sustained cornering Gs are different from what I experienced in Auto X? Correct me if im wrong but also with using the G-tech if I reach a high enough spike in the lateral Gs the car will obviously spin out. With that when it does actually go into a spin that should show me what the peak is that the tires I have can hold at? or does it vary a lot depending on other factors?

Norm Peterson
04-26-2006, 03:09 AM
Your resultant acceleration at any given instant is the vector sum of the longitudinal and lateral acceleration terms, and is not necessarily in either direction (and generally isn't).

[Resultant Acceleration] = SQRT ( [LAT ACCEL]^2 + [LONG ACCEL]^2 )

If you actually did see 0.9g lateral and 0.5g longitudinal at precisely the same instant, the car was seeing a resultant acceleration of just under 1.03g in a direction about 29* off the purely lateral.


06-09-2006, 05:10 AM
.901g at 32.5 degrees. it was .05g not .5, unless it was a typo in the original post right?:hmm:

Norm Peterson
06-09-2006, 01:21 PM
Make that 0.901g at 3.2* and I think we'll finally all be on the same page.

(I must have not looked far enough up the topic before - 1.03g is rather optomistic performance for the tires as described . . .)