Hey guys, so my 08 F250 is running 37 inch tires which is obviously bigger than stock, and I haven't gotten the money to buy a tuner to fix it. My speedo is wrong which also means my mileage counter is somewhat wrong, so what changes do I have to make to my mile intervals? Do I change the oil at 2500 miles instead of 3000?

 

Do a 5 mile speedometer check. See how far off you are in the 5 miles and then scale it up 3000 miles to see how far off you are. Personally, I think it isn't an issue to worry over and just change oil when it hits say 5,000 miles.

If you really want to correct it, you might try to see if the dealer can change the tire size with the Ford IDS.

 

Okie dokie! Thanks!

 

Dealer said they could only adjust for up to 35" tires on my 05' with 37's
I bought a SCT X4 that I thought would fix the the speedo but that only fixed the shifting of the trans...
Bought a hyper tech speedo calibration unit that plugged into the back of the speedo for $200 that fixed it finally. Not sure if the 05'-08' are the same but that's what I ended up doing...