I recently got a SC 3570 to adjust for my larger tires and I did not understand the (stock) numbers that the unit was reading. I am assuming that when you are plugged in and go to change numbers it is showing the stock values and you go from there.

Jeep info is: 11 JK Sport with tow package 6 speed manual

After I updated the 3570 on computer I went to the JK and hooked in (following instructions) when I went to change tire size it was showing 27.x (x for I don't remember the exact number) and the axle gears showed 3.21.

I did buy this JK used but the spare is 225/75/16 (its a goodyear wrangler and looks like it was the stock tire) which converts to 29.3, also with the tow package (which appears factory to me) should have meant 3.73 gears.

Would the programmer have gotten stock numbers from initial information input on home computer (which did not ask for tow package or any other data that might have altered the stock info) or does it get it from the JK computer once it is plugged in?

 

I pulled mine out of the box in the parking lot of 4wheelparts plugged it in programed and that was it. I updated it later so I could turn off the tire pressure thingy and had no problems.