i was going into the custom settings and edge sets the value for my rear end for 3.73 gears. i read edge reads factory pcm and loads its settings into the pcm. after looking into it i have the h9 door code/ verified to be 3.55 on the rear end tag. my question for the last year+ have i been running with the computer thinking i have a 3.73 and what effects can this cause? also is that a edge installed ratio or was that read from the pcm?

 

I had the same problem with my Edge on my 2005. It always defaulted to 2.73 when I had 2.55s. If you don't correct it to what is actually in the truck, the speedometer and ode meter will be off a little, plus the transmission will shift at different points. Since there is not a big difference in those ratios, it is not off a whole lot, but it would be off. Just everytime you load a tune, set the gears to what you know is in the truck.

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The axle ratio set in the Edge is not that critical, but you should "fine tune" it using the tire size function to get the Edge road speed readout to match a GPS.

 

yeah im trying to find a calc now to see what my 305/45/22 equal out to.... i actually never got too into the edge except for the factory edge tunes. have a day off work and no chores to do so i started playing around with it a bit today. set the shift firmness up to 20 and that feels far better!

 

You may think the shifting feels better at +20, but you are putting more strain on the mechanical parts of the transmission at that setting. If you move the firmness too far negative, it will cause unnecessary wear on the belts. So, I would recommend you don't go much beyond +-10 in the firmness settings.

The Edge already increases the "firmness" in the tunes it loads, so you are actually increasing it more.

Ideally, a shift should be firm, but it should not feel like a kid is sitting behind you and kicking the back of your seat. (Thanks Longshot270).

- Jack

 

With the Edge tunes, I ran +9, once I got a custom tune, it was firm enough, I left it alone.

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You don't really need a calculator, you can use trial and error.

 

yeah, i read many use gps to get things (mph) matching, but i dont have mine at the moment. i agree about the shift firmness, putting it down to 10 for now, truck is completely stock besides a cat back exhaust and is my only ride....i need it to stay dependable for daily driving.

 

As for your tire size, try a starting value of 2538mm. That's your "unloaded" diameter of 2617mm minus 3% for "squish" (the effect of putting weight on the wheels). It should be a good starting point. Make sure you set the Gear Ratio to 3.55 too, because the Edge will load a placeholder value of 3.73 as soon as you open the Custom Options Menu if you don't. If the speedometer reads too high with that Tire Size, reduce it until the speed is right. If the speed is too low, increase the TS.

The correct TS and GR should have the dashboard speedometer reading about 2 mph fast at about 70 mph, due to mechanical errors. With this setting, the odometer will be correct. The speed on the Edge, if you monitor it, will be 70 if you are actually going 70 with the correct TS and GR.

- Jack