My edge cts it the exact same way about 3 mph off. I never took the time to try and fix it so I'm clueless there. And as for changing settings yes just put 93 in here and have fun! And run the existing fuel out and put strait 93 in it. You get better results with strait 93.

 

Unless you have changed gears in the truck, DO NOT change it on the Edge. As far a getting the correct mm set on the Edge, mine seemed to bounce around after I set it for some reason, just make sure its the last setting you double check before accepting your new variables and it should set it correctly.

 

Yeah thats strange Summers....I just tried that...I went through the list of setting everything and before I saved, went back and looked at the tire size and it was off by 4? Changed it back, then saved.

Makes me wonder what else may be off or not what I set it at?

 

Agreed, I just learned to set it at the setting right under what mm I needed and it defaulted to the next higher size. Sounds like someone should make a complaint to Edge that this is going on.

 

So if my speedo is reading fast would adjusting to a bigger tire size fix that or should I go to a smaller number? Using the exact size of the tire is off?

 

Numbers will go up, since you're bigger tires have a bigger circumference. The Speedometer needle won't ever match, its built in by Ford to be off about 3%. You want to match your GPS speed to the digital speed on the Edge. Drive 10mi by GPS and make sure that your odometer goes 10mi also.

 

What would I put in the edge for tire size if I have a 35-12.5-17 tire?

 

Edge needs the circumference of your tires in millimeters. So you'd do 35 x 25.4 x π which equals 2,793.
Hope that helps!

 

That does help...thank you!

 

What about a 265/70/17?? I'm sorry for asking but trying to figure out the right millimeter for my edge is so confusing. I think the millimeters typed in right now may be off a little because my speedo is a tad off from my edge speedo. Any help would be appreciated!