Don't know how many of you might be interested in this information, but this page (including the spreadsheet below) will tell you your effective tire friction coefficient.
I almost didn't include a spreadsheet, since the calculation is quite simple. It involves the following:
coefficient = 372.7 L / (372.7 H + B L T2)
where "L" is the wheelbase, "H" is the center of gravity height, "B" is the percentage of total weight carried by the rear tires, and "T" is the 60 foot time.
(The calculated value will be invalid if the indicated weight transferred exceeds the static weight on the front. If you use the spreadsheet and this condition exists, you will get a response indicating the input data is invalid.)