Tire circumference getting changed by Gryphon
 

Hi all. I decided to try a different tune, and even though I hit "load previous settings" my tire size got wiped. I think the default is 2356. I tried to put in values several times, but then when I go back to is (via load previous settings) it was defaulted back again. I know that I read here that the tire size setting is actually a "revolutions per mile" setting. Can anyone tell me where the "notches" are in the available settings? That way I can save a little frustration. Right now it's at 2691, which is a little big for my 275/60/20 tires. If I can know the built in increments on the Gryphon, it would help. Seems like maybe 2591 may have been my value that worked before.

Thanks

Yes, I think 2591 - 2580 would be about correct for the tires you have. I don't know the "notches" you mention, but since the revs per mile value is always an integer, 621 revs corresponds to 2590 and 624 corresponds to 2580. Since your tire sidewall is not too high, I suspect 2590 is very close to right.

The 2691 you say it's at now is WAY too big. The unsquished value would be 2632.

Now, it really sounds like you went to the Tire Size (TS) in the custom options menu before you went to "Load Previous Settings". To get back your previously entered TS (and Gear Ratio) you MUST choose "Load Previous Settings" as the first step after opening the Custom Options Menu. Again, though, due to the way calculations are performed in the conversion between revs/mile and tire circumference, don't be surprised when you see a small change in the value.

- Jack

Thanks, Jack. I did the math last night 5280 x 12 x 25.4 to calculate mm/mi. I set it to 2591 and it's very close. I would guess that I just to figure the next few closest integers for any new adjustments.

I was loading previous settings first. In working with percentages (of error), I had tried 2451, 2568, and 2575 but it KEPT going back to 2356 (I think that was it.) I don't know why, but it seems OK now. Thanks for the info.

Rick

PS-My rear end is stock 3.73. Should I have used something different?

Glad things are working. If your installed Gear Ratio (GR) is 3.73, that is what you should enter (or insure is being used).

The ability to change GR is there for people who mod their trucks in that respect, just like those who mount different sized tires.

- Jack

That's what I thought. Just making certain. I appreciate the info.