I've had my edge on, no problems, everythings reading correctly. But i notice a lot of people ask about their new edge, and if they have a problem, people ask if they set up their tire size right. You dont have to set up your tire size when you install the edge do you? The programmer reads the stock setting for itself. Correct me if im wrong, but if everything is reading correctly, then you shouldnt have to touch any settings like that?

 

Your correct. if you have the same size tires as the stock program is set for you should not have to set the tires size. it will load the factory setting.
however! I had my factory program changed at the dealership for slightly larger tires 265/70's. when I go the edge it still showed the factory setting as 255/70's
you can check it. just to to tire size and it will show the current setting in millimeters. the edge manual will show you tire size in millimeters.

 

Speedo Correction

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Setup of this parameter is definetly trial-and-error.

The Edge manual gives a base line number for circumference of a tire that is fully inflated and does not take in the account of the "squish" factor.

It is best to measure your rear tire by marking it with tape or a marker and transfer the mark to the pavement. Have someone observe the mark on the tire as you drive slowly until the tire has made "one" revolution. Now, measure the distance between the two marks that are on the pavement and this will give you your true circumference of your tire as it is on the truck. Metric tape measure works best or multiply by 25.4 to get the milimeter measurement required to load into the Edge programmer. Don't forget to punch in the correct axle ratio your truck has when programming each time.

Example: My 02 Screw has BFGoodrich LT285/70R17 and 3.55 gears. Circumference, when measured, came out to 2520mm. Not even close to what is stated in Edge manual. Programmed the Edge with these numbers and test drove on a highway with mile markers to check. Number was to low as odometer was clocking more than actual driven. Programmed again with higher number 0f 2552 to trick PCM that tires are larger so odometer will clock slower. Now, for every 10 miles driven, odometer clocks an extra .1 tenth of a mile. Programmed again with lower number of 2548 and on recent trip on RT80 showed that my odometer was only off by .1 tenth of a mile after 100 miles driven.

That's as close to as perfect I think I will get unless I want to be really **** and reprogram the Edge with a number of 2547 but cargo weight and other factors will effect this number in the end.

So, as you can see, this "gray" area is by all means....trial-and-error in order to get it right!
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x2 - chalk and measure. Even if you're running stockers it wouldn't be a bad idea. It's only going to take five minutes. Obviously, make sure your tires are properly inflated. Good point about the gear ratio, too. It defaults to 3.73.

 

thanks for the info. Didn't realize it defaulted to 3.73, cause i sure have 3.55's. Hah, doesn't seem to matter, as its been driving great. But i suppose i'll change it anyway.

 

yeah i need to do it too because i have the smaller tires on my truck.. 275/45R20's