Yup - you need to increase the Tire Size setting in the Custom Options menu. And, make sure your Gear Ratio setting is correct too.

For your tires, I'd suggest a TS of 2482mm (That allows for 3% squish).

- Jack

 

It sounds like you might not have corrected your TS and/or GR in the Gryphon.

When you did your test, did you also verify that your actual distance travelled was accurate?

 

yeah, i used the number that you calculate using your tire size and that formula recommended out of the gryphon manual. that 2482 sounds about what i had. i cant remember exactly. i need to check the gear ratio just to make sure, though. i just assumed the one that came off the stock pcm is correct, but maybe not?


on the odometer? no. i know its not correct for sure now. mainly because i was comparing the distance travelled on my gps during the trip and my trip computer on the message center. it was off by around 4 or so miles every 100 miles the gps said we travelled.
but when i calculated my actual speed i was using the mile markers, so as long as the state didnt screw those up, that should be right. haha.

 

The reason I asked about the mileage is the Ford speedometer is usually 2-3 MPH high and it's my understanding (from my local dealer service manager) there's nothing you can do to correct it (even with the correct TS and GR). I can confirm my 09 (stock tires, no programmer yet) is also 2-3 MPH high compared to my GPS. However, my odometer is dead nuts on.

Since your odometer is also off, then I'm betting there is something wrong with either the TS or GR. Jack gave you good advice on the TS, but if your odometer is reading 4% low (4/100), then you probably need to multiply the current TS value by 1.04.

For your tires, the unloaded circumference is 2560; revs/mile = 629

5% squish = 2431 mm
4% squish = 2457 mm
3% squish = 2483 mm

Hope this helps.

 

AND, if you did not check the GR, it may very well be the culprit. When you open the Custom Options menu, the Edge does not read "stock" values from the PCM for the TS and GR. It loads "placeholder" settings that can be VERY wrong.

- Jack

 

i read somewhere that its a law that automakers have to do that. They do that to also help accomidate for the mechanical inaccuracies. i cant remember the exact percentage that it has to be, but i know they have it...

as far as the size goes, ill have to redo that soon. my battery isnt 100% at all right now though, so im waiting a little bit so i can afford to buy a optima yellow top

hmm. didnt know that. i thought it would replace those stock values into the placeholder. need to check that next time im out at my truck for sure.