[clev]

I went from 275 tires to 295's. The 275 is 34.1 in diameter, 107.1" circumference, and 593 rotations in a mile. The 295 is 35.1, 110" circumference, and 573 rotations in a mile. I should be able to figure this, but I guess that I'm having a senior moment. How do I compute the error in the speedo.

Also, the SCT X4 only allows for a 34 inch tire; does that have any effect on the speedo when the tires are an inch taller?

 

[Maryland dieselnick]

Clev, 20 rotations difference in a mile,,,,is going to add up to a neglible amount difference in my mind but RT.(wiz with such things), I bet will be along shortly to tell you the amount.

 

[RT]

Multiply the speed you see on your speedometer by 1.035 to get the corrected speed. So , if you show 70 mph, you are really going 72.44 mph. If you have AE, you can correct the ABS module to the new tire size.


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[clev]

Thanks, RT. I thought that my speedo would read faster than actual speed; glad you corrected that thought. I have had Auto Enginuity for about 10 years, but have used it very little. Is there something in it that will allow me to correct the speedo?

 

[Maryland dieselnick]

Clev with an AE version that old, I don't believe you can do your new truck. You can contact them and buy the newest version (contains Nick corrections and some added items they had omitted on the 7.3That was real fun..not!) that now has the newer trucks on it, for about $150 if I am not mistaken.

 

[Maryland dieselnick]

Clev with an AE version that old, I don't believe you can do your new truck. You can contact them and buy the newest version (contains Nick corrections and some added items they had omitted on the 7.3That was real fun..not!) that now has the newer trucks on it, for about $150 if I am not mistaken.

Give Emmanuel a call their and inquire. Tell him the version you have and he can set you up, probably with just an email sent to you but not positive.

 

[RT]

I missed we were talking about a 2017, but I'm sure Manny can figure it out. The speedo gets its input off the ring gear in the differential. If it's spinning a what it believes is 70 mph with the original tires, larger tires will move you faster down the road.


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[clev]

Ok, I got lost here on something. My truck is 2012. My AE was bought in ~2005 for my 7.3, but it also works with my '12. And, I have updated it as recently as a couple of years ago.

 

[Maryland dieselnick]

Alrighty then, I believe you can don't remember where. I never have a need. Have you clicked around with it on your truck to see?

 

[clev]

Not yet, but I will.