Stock tires are 245/75/16. Want to go to 235/85/16.

Do I need to buy a programmer or will it be okay without. GM tells me they have no patch codes for the 3/4 tons. I understand it could affect ABS and shift points as well as speedo of course.

I am thinking this slight change in OD wont have much effect on anything.

 

I have 255/85/16 0n my 03 HD with cranked t-bars minor trimming on plastic in wheelwell.Have 235/85/16 on my 02 HD with no modifications.The dealers are full of doodoo on the abs and tranny stuff nothing to worry about a tire 1 inch taller will not harm anything.Tach will show about 100rpm less at 70mph.If you put 36s on it your abs would act weird in a panic stop,tranny wouldnt shift into od until 80 mph.235 are okay

 

Thanks, thats exactly what I wanted to know.