I put 35" Toyo tires on my F250 6.0L truck. I love the tires, but now I have two problems. My speedometer and odometer is off. Also my LED computer display that tells me my fuel mileage says 9.9 mpg. Ford can only calibrate up to a 285 size tire and I'm chummy with the mechanics at the Ford dealer. However, they can't help me because my tire size is 315 75 16 (35" tires). I lifted the truck about 3" by adding a leaf spring on each four corners. I love the look, the height, the ride.

My delimna is how to fix this? How can I get an accurate speedo, odometer and fuel mileage readout on my overhead LED gauge?

Stumped.

Thanks ... Skigalini

 

Superlift makes a tire size compensating device for most vehicles. Not sure about the new SD.

 

There was a post on here a week or so ago from a guy who put some type of electronic speedometer/tire size compensator on his truck and ran into all kinds of wierd and serious problems with the electronics of the engine.
His post started out with all kinds of terrible things that were happening to his new truck, stalling, refusing to start, poor performance, odometer going "-------", everything.
He then went on to say how the dealer was mystified and couldn't fix it after being towed-in several times, and he was mad at his truck and the dealer.
Then, after a few other people posted trying to be helpful, he re-posted saying the dealer had "found the problem", It was his electronic speedometer compensater that he failed to mention to anybody that he had installed.
I'm not sure the aftermarket is up to speed on all this new stuff yet, and I would beware.

BobJonesSpecial.

 

Thank you 'BobJonesSpecial'

I take this as good advice and in reading some of your postings, you seem to be knowledgeable about these PSD's. I might hold off until something becomes more proven.

Still open for any other remedy suggestions to the speedo being in-synch with the 35" tires.

Skigalini