Sportsman Matt
Adventurer
Hello again, I've been racking my brains trying to figure this one out.
I swapped out the factory P255/70R16 tires on my 2002 GMC Sierra 1500 for the LT265/75R16E Grabber AT2 by General because I have a slide in camper and need the load rating. When they put the tires on the tire guy said that the speedometer would be reading under by 1 or 2 miles per hour.
I took a Garmin Nuvi 200 GPS with me and found that at highway speeds I was 6 MPH faster than the speedometer. So I took it to the GM dealer to have them fix it.
After 3 hours they told me that tey couldn't program the tire size into the computer because GM doesn't support that particular tire size. But they were able to reprogram the ABS computer to recognize the new tire size, and I would have to spend about $400 on an aftermarket computer programmer to program the speedometer.
So I left and called a couple garages, one took me in and showed that the computer was already programmed for the tire size in question and the speedometer should be fine. So I left, picked up the GPS and now I'm reading 2 to 3 MPH under what the GPS says at highway speeds.
Now before this I know the speedometer was dead on, even at highway speeds, but now I'm a little fustrated because the solution is to spend more money on something that shouldn't have been that tough to do in the first place.
Any ideas or suggestions? The garage is willing to play with the programming, but that will cost as much or more than a programmer for the computer.
Definately fustrating. All ideas are welcome.
I swapped out the factory P255/70R16 tires on my 2002 GMC Sierra 1500 for the LT265/75R16E Grabber AT2 by General because I have a slide in camper and need the load rating. When they put the tires on the tire guy said that the speedometer would be reading under by 1 or 2 miles per hour.
I took a Garmin Nuvi 200 GPS with me and found that at highway speeds I was 6 MPH faster than the speedometer. So I took it to the GM dealer to have them fix it.
After 3 hours they told me that tey couldn't program the tire size into the computer because GM doesn't support that particular tire size. But they were able to reprogram the ABS computer to recognize the new tire size, and I would have to spend about $400 on an aftermarket computer programmer to program the speedometer.
So I left and called a couple garages, one took me in and showed that the computer was already programmed for the tire size in question and the speedometer should be fine. So I left, picked up the GPS and now I'm reading 2 to 3 MPH under what the GPS says at highway speeds.
Now before this I know the speedometer was dead on, even at highway speeds, but now I'm a little fustrated because the solution is to spend more money on something that shouldn't have been that tough to do in the first place.
Any ideas or suggestions? The garage is willing to play with the programming, but that will cost as much or more than a programmer for the computer.
Definately fustrating. All ideas are welcome.