Here's the deal for all of us with bigger tires and wheels, I just installed 22.5" Alcoas with Yokohama 255-70R22.5 ( tire height is approx. 36.3" ) tires and needless to say my speedo was way off!
Went to the Dealer and it took about 10 minutes the tech plugged in to the port under the dash and set the tire revolutions per mile to the specs per Yokohama for my tires, Apparently our speedometer is set by tire revolutions per mile per tire mfg. specs. and my new tires spec. out 571 rev. per mile and the old tires were set at 674 revolutions per mile.
Now when I started asking questions the tech did say some years and models of our trucks are different as in the max tire diameter or rev. per mile that the computer will let you enter, he said the 03 can do about anything ( I guess I lucked out being an 03) He did say one possible side affect on some trucks when they reset speedo the ABS light stays on til about 20 mph. but I had no issues.
So for all you running 35" tires go to the tire mfg website and find out the rev. per mile and go to the dealer
P.S. Only cost me 30.00 Alot less than a speeding ticket for guessing how far off speedo is and find out from police that I figured wrong
And I cant wait to see what my Hwy mileage is now...

 

Why worry about it? Just figure out exactly how much faster you're going (gps).... think about it.... youre mileage will be 5-10% more than what your odometer reads... hense.... more warranty.... ????

 

Makes a big difference.. the shift points and ABS are affected by larger tires..

With my 315's I could not get the converter to lock up untill almost 60 MPH. Most of the freeways around here (due to traffic) never get over 50 or 55.

WIth the Speedo reset I get TC lockup at about 47 to 50 MPH

Makes a BIG difference

Gerry

 

TC Lockup at 47 to 50 WIth 315's??? I had my spedo recalibrated for the 315's and I lockup at 60. ***?

 

I need to get my 35's recalibrated also. I went to my local dealer and they wanted $99 for it. Screw that, i'll watch my speed and if I do get pulled over i'll say they were just put on and their out of calibration.

But honestly i'm headed over to another dealer to see what they charge.

 

If you know someone that has a Smarty they can calibrate the speedo for you.

 

Both dealers here in Dallas/Plano have quoted me 76, and 89 dollars to reclaibrate my speedo, where in the heck are you guys getting yours done for $30???

 

I was willing to pay an hours labor at the very most so when they said 30.00 I told the tech I would buy him lunch

 

I had to call around to couple dealerships to get mine adjusted for $47. As a matter of fact I finally called 3 different service advisors at the same dealership to finally find one who would do it for an acceptable charge. And BTW, my TC won’t lock till about 58 mph. It used to lock at 50 mph with the stock size tires.