Matthewd5

if it's set for 37" it's off by almost 10mph at highway speeds...when set for 30" it's within 1-2 mph at highway speeds

the big question is if this going to freak out the Jeep's computer? The odometer is working just fine and I've got the manual so no shift points, but it just feels stupid having it set 7" smaller than the tires!

matthew

Monte417

That is incorrect you must be setting the dip switched incorrectly

ronjenx

To get an accurate tire diameter, stick a piece of chalk in the tread, and drive forward until the chalk leaves two marks.
Measure the distance between the marks; divide by 3.1416. That will be the tire diameter as the computer sees it.

Matthewd5

I wish it was that simple, I've replicated it three times now...

I'm only setting the dip switches wrong if the Procal reference card has errors in the shown settings

matthew

Matthewd5

I will try that, but starting at 37" and cross referencing with a gps that has been double checked to make sure it's accurate, and reducing the size setting till the gps matches it be just as accurate or am I missing something simple??

your tech tips have always been dead on in the years I've been on here!

matthew

bombout800

I had to play with mine a good bit to get it on the money. When I adjusted down from a 35" every .25" or whatever it was, made a pretty good difference. It's still not dead on at every speed, but within 1mph at the worst

Matthewd5

Normally I'd be doing that next, it's just the gap from 37" to 30" has me thinking that something's wrong somewhere...

matthew

Rebar-7

Call AEV see if they can help, mabe someone on here can give you the position of there dip settings used for 37s. Worth a try...

Mark Doiron

I agree. Five possibilities:

1. The Jeep software is messed up somewhere.

2. The Procal software is messed up somewhere.

3. The Jeep hardware is messed up somewhere.

4. The Procal hardware is messed up somewhere.

5. The settings you used are somehow incorrect.

I give 1 and 2 little chance of being a problem since your case seems to be the first time this has happened. Ditto for 3, but because presumably your Jeep speedo worked well before. As for 5, disprove it by having someone else re-do ALL of your settings. That leaves 4. Perhaps one of the dip switches is stuck in one position, so some functions work properly, others don't. Contact AEV.

jadmt

how about posting a photo of how your dip switches are positioned for comparison?