My 04 has 255/70 R17's from the factory
I'm thinking about going up one maybe two tires sizes, my question is what will I need to do to recalibrate the speedometer, do you have to buy a programer, or is there another way?
thanks for the help,
Matthew

 

You'll probably need to have the dealership do it ... provided the difference is great enough to warrant it. My dealership told me it would cost about $100 to recalibrate. I passed.

 

buy your self a super chips tuner and do it your self plus have more power

 

Do you have the superchips? How did it affect gas milage? I have heard reports of better milage as well as worse. Could you feel the power difference?

 

With my diablo predator set on the peformance program and retarded 4%, I can run 89 and routinely bring in 18-19 mpg at speeds of 65-70. If I slow it down to 55 mph, 20 mpg is not out of the realm of possibilities.

Keep in mind that my location is fairly flat in terrain.

 

i have a 2006 supercrew lariet with the 5.4 liter engine. It has 20 inch wheels and tires and my gas milage reads 13.9 all the freaking time, it never breaks 14 mpg. with the 20 inch tires how much, what percent do you think my calibration is off? any suggestions?

 

go to tirerack.com and somewhere on their site is a table that tells you how to calculate all that,like speed and rpm's etc.

 

Try this one ... just input whatever data you have available:
http://www.discounttire.com/dtcs/infoTireMath.dos

 

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With such a new truck, your mpg will not be as great as it could be. It takes quite a while for every thing to break in and mesh correctly.

Sometimes it takes as much as 10,000 miles. Driver habits also have a lot to do with it too.

 

I get that mileage in stock trim 18 to 19.8 @ 75, 20.1 below 70. 04 5.4 SCREW Lariat 3:73 LS.