Posted 2008-10-10 8:55 PM (#2352) Subject: Need Help!
Posts: 7
Location: vanceboro, nc
I need someone who can help me figure something out on my truck. It has the trip computer in it that tells fuel mileage and such. I decided to check it the old fashioned way by keeping up with the miles traveled and then the gallons of fuel put back in. Well it turns out the trip thingy is way off. The truck is an F250, 7.3 diesel. It has 18 inch tires (fat tires) and 18 in rims. Would that mess up the trip computer and if it did, would the fuel mileage be better than what I'm seeing or worse? I can't figure this, don't know how the tires and rims would work with the computer. I just thought big tires would help the fuel mileage. Would appreciate any help!
Posted 2008-10-11 11:48 AM (#2353 - in reply to #2352) Subject: RE: Need Help!
Location: Colorado
I think if your trip computer is off, so would be your odometer. One way to check your odometer is when you are on a highway with mile markers, note your exact mileage including tenths at a mile post. Then check it 4 or 5 mile markers down the road. It should be exactly the same(for example 31,243.8 and then 31,248.8). If it's off, you can with a little math, figure what percentage it's in error. I don't think any of my trip computers, car or truck, have been real accurate!
Edited to add: If your odometer is way off, you can go in to your dealer and he can reprogram your vehicle for the size tires you are running.
Posted 2008-10-13 5:40 PM (#2356 - in reply to #2352) Subject: RE: Need Help!
Posts: 6
Are you getting better milage than the computer? In my experience with my trucks, the bigger tires kill your fuel economy. Is your truck lifted or stock suspension. Computers are programmed using stock rims and tires. There are downloaders you can get to adjust this if you like.