speedo re-calibration

[MillerTimeX17]

after putting new 265/75's on the EX i noticed that my speedo was off by 5-6mph, according to my gps. will a shop or dealership be able to hook up the PCM and change the comp to adjust for the larger size tires or can i get a new speedo gear? It is an 05 XLT 4.0 auto4wd

also... has anyone put new gears in their 3rd gen?? i was looking for some 4.10s

 

[techieman33]

A dealer can recalibrate the speedo. Another option is to buy a performance tuner that would allow you to do it yourself, as well as pick up some extra power, or fuel economy.

 

[MillerTimeX17]

i take it that you are talking about the SCT x-cal II? i wish i had the money the buy it! but in the past month i have bought the body lift, tires, muffler, custom piping, scan guage II, and a new headunit. so i dont have much left in the budget.

 

[techieman33]

Yes that's what I was receding to. A dealer will probably charge you an hour of labor, which gets you 1/4 of the way to buying you a tuner.

 

[MillerTimeX17]

has anyone used one of these:

http://www.summitracing.com/parts/JET-50109/

 

[techieman33]

has anyone used one of these:

http://www.summitracing.com/parts/JET-50109/

Stay far far away from that piece of crap. My brother bought one to use on his dakota and it sucked, it took him over an hour to get it adjusted right. And it wouldn't hold the calibration, so he would have to redo it about once a month to keep his speedo accurate. If your going to spend that much money you might as well pay the dealer to do it.

 

[MillerTimeX17]

ok cool. good thing i didnt order it then. i was about this -> <- close to buying it today

 

[Gus Gorilla]

Just a side note on using GPS such as TomTom or Magellan to measure your speed. I'm sure your different sized tires caused yours. However, GPS units are Not accurate. They're not required to be by law, where vehicles are. Which is why if you get pulled over and tell The Fuzz your TomTom said you weren't speeding, he or she will laugh as they write you a ticket. I've got 2 TomToms, (mine & wifes) One reads 3mph slower on highway, one reads 4mph faster. At the same time, in the same vehicle.

 

[MillerTimeX17]

Just a side note on using GPS such as TomTom or Magellan to measure your speed. I'm sure your different sized tires caused yours. However, GPS units are Not accurate. They're not required to be by law, where vehicles are. Which is why if you get pulled over and tell The Fuzz your TomTom said you weren't speeding, he or she will laugh as they write you a ticket. I've got 2 TomToms, (mine & wifes) One reads 3mph slower on highway, one reads 4mph faster. At the same time, in the same vehicle.

yeah my tom tom was reading 2mph below my speedo and then now its 5 mph off.

 

[macknos94]

actually satelites are closer then your vehicles speedo. when i took my mounty in to have the speedo changed for my tires they were saying that that is the most accurate way to set your speedo. i have a garmin oregon 550 and its dead on with my speedo right now