Adjusting Speedometer

[WileE7]

I have a 90 Bronco w/3" lift and 35's, I was following my wife on the highway to drop her car off and noticed I was passing people going 55 I called her to ask her how fast she was driving and she was doing 64 /emoticons/[email protected] 2x" width="20" height="20" /> . How can I adjust my speedometer to have an accurate reading for how fast I'm going? Do need to buy a chip or a tuning computer? Whatever I need to do the cheaper the better

 

[Justshootme84]

I would get a true speed reading with a GPS unit if possible (or at least compare to a stock car like your wife's) to figure how far off you are at various speeds. You may be 15-20% off at 55-60, and have to just keep your speed down more than in the past. IT may be possible to change the speedometer drive gear in your transfer case to a different size, have to check with your Ford dealer for the right one. SuperChips makes a programmer/chip to re-calibrate the speedo, but that's for 96-up. Even my new Dodge truck with 33's is off by 10-12%, according to the deputy who ticketed me last month. So for now, I just drive 55 on the dial to go about 65, like I had to do with my 84 Bronco with 35's.