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Crusty's 75th Annv PW #1590 build/mods adventure

Now that a bunch of mechanical stuff is done, a switched my attention to programming.
Using the AplhaOBD, I figured out how to hook everything up and got it all working on my laptop.
I changed my tire size to match 34.5" tires I have on it and also changed the TPMS to 30 PSI all around.
Uploaded the changes and saved the file. Thought I was done, went to start the truck and had all kinds of faults that I couldn't clear.
I've been watching Charles Pages on youtube, so I went back to his video on changing tire size. In it, he shows how to clear all the faults. Guess I should have paid more attention. Followed his directions and got all the faults cleared.
I then went and lowered my tires. 40 front/35 rear. I was running at 55 all around as that was as low as I could go without having a TPMS warning. I noticed when I was working under the truck that the outer lugs on the tires were not touching the ground, so way over inflated for a empty truck.
With the lower pressure, tires are making full contact now. I'll see how they do and adjust as necessary.
 
No, didnt do the windshield. Not sure its legal.
I had the same stuff on my other vechiles.
Did really believe the hype at first, but had it put on my car anyways. Made a believer out of me.
I could sit in the car, with shorts on, sun shining on my leg, and my leg never got hot.
So now I put it on all my vechiles.
 
Crusty old shellback said:
No, didnt do the windshield. Not sure its legal.
I had the same stuff on my other vechiles.
Did really believe the hype at first, but had it put on my car anyways. Made a believer out of me.
I could sit in the car, with shorts on, sun shining on my leg, and my leg never got hot.
So now I put it on all my vechiles.
Click to expand...
I dunno about where you are but it’s 100% not legal here but cops have way more important stuff to worry about than my tint. Ymmv
 
So I went and downloaded a GPS speedo apm on my phone to see how close I am with the reprograming of my bigger tire size.

BFG and others state that their 35X12.50 17 KO2's are actually 34.5" in diameter. So I used that number to convert to circumference in CM, which is what is needed for the program.

Checking with the GPS speedo this morning, it looks like I am 1 to 1.5 MPH higher on the truck speedo. I checked it at several different speeds. Setting the cruise control and comparing the speed to the GPS app on the phone.

So I'm going to redo the calculations and use 34.75" and 35". I'll see how those numbers work in getting a correct MPH reading.

I'll report back what I finally come up with.
 
Out of the three trucks I've installed them on, this was the hardest.

I've done a '04 Chevy 1500, '01 Ford f250, and this one, '21 PW.

If you have any questions as you go thru it, ask away. I read the directions several times before I started, and I still had to figure a few things out.

Hope what I did helps out some. To me, that's the benefit of doing these build threads, helping each other out. :)
 
Well I guess my mind was not working right. Or I was wishing for something that wasn't. :rolleyes:

I reprogramed the truck for a tire size of 34.75". Now my speedo is off by almost 3 MPH. :oops:

I wasn't thinking right. I need to go smaller, not bigger. So tonight I'll reprogram the tire size to 34.25" and see how that does. Should be close.

And as an FYI tires are BFG KO2's 35X12.50R17 on the factory rims running 40PSI front, 35 PSI rear.
 
Crusty old shellback said:
Well I guess my mind was not working right. Or I was wishing for something that wasn't. :rolleyes:

I reprogramed the truck for a tire size of 34.75". Now my speedo is off by almost 3 MPH. :oops:

I wasn't thinking right. I need to go smaller, not bigger. So tonight I'll reprogram the tire size to 34.25" and see how that does. Should be close.

And as an FYI tires are BFG KO2's 35X12.50R17 on the factory rims running 40PSI front, 35 PSI rear.
Click to expand...

Break out a tape measure and actually measure the tires installed. I'll bet they are closer to 34". You tend to have to go an inch below what the size is to get the speedo correct (in my experience)


.
 
MtnRider said:
Break out a tape measure and actually measure the tires installed. I'll bet they are closer to 34". You tend to have to go an inch below what the size is to get the speedo correct (in my experience)


.
Click to expand...

Yep, if not smaller.
 
Yea, I know they are not 35". Online says 34.5 so that's where I started. Just went the wrong way. 34.25 should be about right.
 
HMM. Well I originally programed for 34.5" tires and was off by about 1.5 MPH. redid the programming to 34.75" and now its almost 3 MPH off. So with that in mind, 34.25 should be spot on. :rolleyes:
 
Crusty old shellback said:
HMM. Well I originally programed for 34.5" tires and was off by about 1.5 MPH. redid the programming to 34.75" and now its almost 3 MPH off. So with that in mind, 34.25 should be spot on. :rolleyes:
Click to expand...

I went back and forth on mine to get it right. Air pressure makes a difference too. I was messing with my pressures and through in another variable.
 
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