I recently put some 275 70 r18s on my 2011f510 from the stock 265 60 r18s. My milage was 8972 when I got the work done. Its been almost two months and my odometer reads 9817.6. I don't drive as much as others. I had the truck reprogrammed several days after the the tires were put on. Question, I feel like the odometer was adding up faster after the tires were put on and even after the reprogramming was done. It was with factory ford programming tools. What could be the problem? The time between driving before the reprogramming or not adjusted properly?

I did do an experiment. Drove from several points and back home. Added the miles. Then used google maps to check for accuracy. I was actually 2 miles less than what google said. Any advice would be appreciated. yeah I know I don't have a gps.

 

I'm not so sure Google maps is all that accurate.

If you can drive a fairly long distance on a highway where there are mileage markers, like an interstate, you could get a very accurate check. It would be good if you could drive a distance of around 100 miles to get a real check.

- Jack

 

Yes I agree. What about ford dealers? Shouldn't they be able to get it spot accurate with the diameter size? I just have a "gut" feeling its moving to fast. I don't drive very far.

 

When checking with my GPS the speedometer is about a 1.25 MPH off, reading higher. Thats with OEM tires on the truck. Then if I drive an average 30 mph for 4000 hours = 120,000 miles I will actually drive 5000 miles less or 115,000 miles. I think I'll put bigger tires on it to when OEM wear out. There is a formula for figuring the diameter of the tire vs distance traveled to get an accurate answer. LOL

 

I don't know if this applies to other tires but I know for fact my 33s are 32" tall so there is room for error...

 

Question everybody. I'm leveling out my front end with 2" kit. um putting 20's on instead of my stock 18's. Bully Dog tuning system. Flowmaster super 10 series muffler. And 33" tires on the 20" wheels.

Am I going to have to tune my speedometer to make up for the add ons or no?


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Yes. Bigger tires will make the speedometer slow.

 

One of my trucks reads 65 mph and the GPS says 68 and the other reads 65 and the GPS says 63 MPH, while the 3rd. says 65 and the GPS agrees. The 2008 is the only one with OEM that is right. I know the GPS is within 30 feet of accuracy. It tells me when I have passed an address immediately. I only believe the GPS, everything else is BS.