Does anyone know of an adjustment that can be made to calibrate speedometer error? I went from stock to H2 Wheels & tires (315-70-17), after a leveling kit from; Off Road Unlimited in Burbank, California. http://offroadunlimited.com/new/whats_new/whats_new_inside_index.html

I'll post pictures later next week. Thanks

Hey Cadent44, i am also running 315/75/16 BFG AT on my Weld Racing EVO Velocity 16x8 rims. I used the HyperTech programer to add power and also to adjust speedo for the tire change. No errors and now I am running at posted speedo speed.


Here's my rim and tire:


http://www.dieselplace.com/forum/uploads/Z1C_315-75-16_fit.JPG

GM will not give the adjustment needed, however you can purchase a few different programers like Bodysurfer did and adjust it that way. I tired getting GM to do this for me, but they refused. Now I'm just waiting for some $$$ and I'll be following in the footsteps of Bodysurfer!

Correct....GM will only give a program on certain tire size changes


ie: if the veh came stock w/ 265/75/R16's GM would support a change to a 265/70/R16 . It's a rollover liability concern...


sorry....but they are comming out w/ a 20" rim option on the C/K trucks.


hypertech has seemed to work well as far as correcting the problem


WARNING......Remove the program prior to taking to a dealership they may update programming in the PCM and erase your hypertech program.