Changing tires, need help...

[xstang]

I'm thinking about going to the track this weekend, but always have problems with my track tune and calculating shift points. My car is shifting perfectly now, so do I just have to put in the new tire diameter and hit autoscale?

Seems like it never works when I go to the track.. I end up slamming the limiter, or it won't shift correctly.

2008 A6 Z51..
My stock tires are 26.64 (per Hp tuners).. My new tires are BFG drag radials 18 inch rim 26.2....

If anyone wants to share the track tested shift mphs for 18 inch Bfgs on a
z51 w/2.73s, I'd be greateful.....

[transam_151]

use the calculator at the top and type in the tire size then go to spedo and enter the inch size with decimal too. Also how close is your rev lim to the shift point. It has to meet a window rpm vs. mph and if not it wont shit. I think its 2 mph for ever 100 rpm increment.... so 20 mph per 1000 rpms. Mite try the calculator then enter it and also add a couple of mph in the gear its banging in if not all the gears. Hope it helps if not post the tune