Speedometer Re-Calibration Question on Recent Rim/Tire Swap GMT900

djklatt · August 24, 2013

My truck is a 2007 1500 extended cab 2wd. I recently went from the factory 245/70r17's to a set of the Z71 style rims with 265/65r18's. The speedometer is around 2 miles off, reading 60 when GPS speed is 62. When I had the TPMS sensors reset, I asked the dealership I usually go to if they could re-calibrate the speedometer for the slight change. They weren't able to do it. I know it's not a big difference, but I prefer everything being accurate. Does anyone know if a dealership can actually calibrate to that size, or if not, what aftermarket programmer is recommended to make the changes. Thanks for the help!

Also figured I'd share before and after pictures:

jimlem · August 24, 2013

Yes, any decent tuner can recalibrate your speedo based on tire size changes. Justin at Blackbear did my last truck when I went up to 33" tires. Worked fine from then on.

pendragon · August 24, 2013

I used a Diablo on my 2010, If in doubt use a speed test App on your phone to confirm that the calibration is spot on

djklatt · August 26, 2013

Thanks for the responses! I think I'll go with a tuner as my truck is stock at the moment as far as anything other than rims/tires, and interior as well as a few OEM style mods. That way in the future I can get a custom tune. I'm probably going with the Diablo inTune that way I can always buy a custom tune for it down the road when I do more performance oriented upgrades. I'll make sure with a speed test app that it is spot on when I re-calibrate it. Now on to selling a few things to afford the tuner.