Speedo on 21s

[TrucksterZ71]

Anybody have any luck recalibrating speedometer on the 21s? With 35 inch tires being a possibility now I’m curious if hyper tech or other products can do that or if the stealership has the ability. I recall the computers being locked down on these last I checked.

 

[big18gordon]

From everything I have seen/heard, the dealership can't even recalibrate the speedo. They can make a change if you are going to another size of factory wheel/tire combo but that seems to be it. Hopefully the aftermarket will figure something out, but it isn't looking good to this point.

 

[MightyWhitey]

My dealer tells me it requires a software update from %GM