I own a 2004 For F150 5.4 V-8 4x4. I have 275/70/R18 toyo mud terrains. I am having problems understanding what size I should put into my edge evolution I think they want you to put in the size in mm but I wanted to check with you guys first. Also in the manual its ays to increase gradualy what incruments should I out in in untill Iget to the right tire size?
I provided what the manual says below.

Tire Size

The

Evolution FORD 4.6 and 5.4 Liter

21

The following table will help you determine your tire circumference by
matching your tire size with the common sizes listed. For example, if your
tire size is 285/ 65-18, the value (circumference) you enter into the

is 2600. You may also use the formula provided to determine your
approximate tire circumference. Finally, you may also measure your tire’s
circumference by marking your tire and rolling it one complete revolution
and measuring the distance in inches or millimeters. If you measure in
inches, multiply the distance by 25.4 to convert to mm. (ex. 91.3 inches x
25.4 = 2319 mm). The range of change is from 2000mm to 3500mm in
increments of 1mm.

Width Ratio Rim Circumference Tire Size

265 70 16 2441mm 33 2632mm
275 70 16 2485mm 35 2792mm
305 70 16 2617mm 37 2951mm
215 75 16 2289mm 38 3031mm
245 75 16 2430mm
265 75 16 2524mm

285 75 16 2618mm [(width * ratio * 0.02) + (rim * 25.4)] * 3.1415
295 75 16 2666mm

305 75 16 2713mm 1. Multiply

315 75 16 2760mm 2. Multiply

325 75 16 2807mm 3. Add Step #1 with Step #2
265 70 17 2521mm 4. Multiply Step #3 with

285 75 17 2698mm 5. The result will be the circumference of your tire in mm.
315 75 17 2840mm
275 65 18 2559mm
285 65 18 2600mm
285 60 18 2510mm
325 60 18 2660mm

When adjusting the following values, it is highly advised to make gradual
changes as opposed to aggressive changes. This will help avoid possible

engine or transmission damage.

 

I would try 2540 (4% squish factor) and then adjust from there.

 

your that man shotgun thank you

 

Also it says in the mahal no to bump the tire size to drasticaly so in what increments would you suggest

 

If your speed is close with 2540mm, adjust up 1% (to 2566) to increase speed or down 1% (to 2514) to decrease speed.

The number you are entering is telling the computer how far you are travelling each time the tire rotates (circumference of the tire). The unloaded (properly inflated) circumference is 2646mm. When you put a load on the tire it decreases the travelling circumference. Most people find the squish factor is between 3 and 5%.

 

I have 26" wheels with a 305/30r26 tire just wondering if anyone has gotten that size to put it into the edge evo. i dont think my calculations are right.

 

Why would the distance around a tire change just because there is a load on it? It might sag and not be as tall but that wouldn't change the circumference.

 

I know this thread is pretty old but I just got my Edge Evolution Programmer, I want to get the correct measurement in MM and I'm having trouble with the formula provided. I'm running 35/12.50/R20's. Thanks in advance.

 

Hi.

Yer kidding, right?

The procedure is in the manual on page 17 - including a handy chart.

To cipher is simple:

35 x pi x 25.4 = circumference without weight on the tires.

Always Multiply that result by 0.97 to account for the "squish" caused by weight which will give you a good starting point. (3% squish is the common correction factor to begin with)

So - 2792.875 x 0.97 = 2709

Also - Make sure your Gear Ratio is correct whenever you open the custom options menu! It might need to be changed. Do NOT assume the Edge will insert the correct value.

If you can, fine tune it until the Edge's speed (not the speedometer) agrees with a GPS.

good luck
MGD

 

Thanks MGD,

Thats what I got I was just trying to make sure I was right.