Tire Size and Gear Ratio

 

here's my pass against a guy who can't keep his mouth shut...

http://www.youtube.com/watch?v=MpsTPsvnoU4

 

oh ok... i'm not to sure what gears i have but i have corrected the tire size through the programmer...

 

What is the axle code on the door jamb sticker?

 

idk but i'll check it tomorrow

 

 

3.55=h9

 

That's correct - 3.55 limited slip.

 

Meh... I miss my 4.10s I had in my other truck...

 

ok with the programmer isn't it suppose to be able to tell what all came stock on the vehicle when you plug it in?? when i redid mine last night it said i had 3.72?? now that i changed it to 3.55 my speedo is now higher then my gps shows... the tire size is correct as per what is shown in the booklet (even did the math)... back to the drawing board to try to get my speedo close to where it's suppose to be...

 

How can a programmer tell what your axle ratio is? YOU have to tell the programmer what it is..........

Same with tire size.

 

^ The VID block in the PCM.

https://www.f150online.com/forums/3845794-post9.html

https://www.f150online.com/forums/3846009-post12.html

For OEM values - that's how it's supposed to know - but sometimes it simply doesn't work -so it's always wise to enter/confirm both TS & GR yerself ...

MGD

 

ok so i can't figure it out...

GR: 3.55
TS: 265/70R18 > 2601.76 (rounded up to 2602)

not sure if what is shown on speedometer is correct or if my gps is correct...

 

Your GPS should be accurate, as long as you give it a second or so to "stabilize".

But, your Tire Size (TS) is too large. You are not accounting for "squish". I'd reduce it to about 2524. If you enter 2602, it should make your truck's speedo read much higher than it should. When you get everything right, you should probably see 72 on your dashboard speedo if your GPS is showing 70. This will make your odometer correct.

- Jack

 

I'll try adjusting the TS. In Houston about to head back to College Station... Will see if that works... My gps is usually accurate.