gear ratio question

[srcracing]

I hope this question makers sense, so here it goes. What MPH speed is a good target when autoX. I understand that each coarse is different, but trying to figure out what transmission ratios I should use in the T56/TR6060. I'm running a 345/30R19 27.12" rear tire and a 3.50 rear axle ratio. So just trying to maximize the second gear ratio to fit best.

[nokones]

I have the Tremec TKO600 with a 3.54 rear diff ratio in a C4 Corvette. MY TKO has a 1.89 second gear and I believe that would be about 76-79 MPH. My car will pull very well off a slow turn but, I have a good torque curve with lots and lots of power.

I believe the 1.89 is the middle of the road choice for most courses where you seldom need third gear. The C5 ZO6 and C6 Grand Sports run with a 2.07 second gear and that is a great gear for the tight stuff but, you will find yourself shifting a lot between 2nd & 3rd gears on most courses. The C6 ZO6s run with a 1.78 2nd gear. I would not go taller than 1.78 and shorter than 1.89.

Oh, I forgot to mention that I run with a 335-18 tire on the rear.

I hope this helps.

[Randy67]

The stock gearing in my 2012 Camaro SS works well in autocross so far. 2nd gear goes to 74 mph, with a 3.45 rear axle ratio and 275/40/20 tires, 28.7 diameter.

Transmission gear ratios are:
First: 3.010
Second: 2.070
Third: 1.430
Fourth: 1.000
Fifth: 0.840
Sixth: 0.570
Reverse: 3.280

nokones recommendation is a good one, especially with shorter tires than I have.