Rough Country Spedometer Calibrator

[Mkcagle]

I added 33s to my Sport S w/max tow. The Speedo was initially reading low about 4 MPH at 70 MPH. Went with simple and relatively inexpensive RC calibrator. Had to reset and go for another test drive several times fine tuning the tire size input to get it spot on comparing to 2 independent GPS systems. Ended up setting to 32.25 to get matched readings.

Sponsored

 

[BMcD]

I added 33s to my Sport S w/max tow. The Speedo was initially reading low about 4 MPH at 70 MPH. Went with simple and relatively inexpensive RC calibrator. Had to reset and go for another test drive several times fine tuning the tire size input to get it spot on comparing to 2 independent GPS systems. Ended up setting to 32.25 to get matched readings.

What was your actual measurement from the top of the tire to the ground?

 

[Mkcagle]

What was your actual measurement from the top of the tire to the ground?

I believe they were 32.5 mounted on the truck. Raining, will double check later.

 

[BMcD]

I believe they were 32.5 mounted on the truck. Raining, will double check later.

My 34’s has an actual measurement of exactly 33” and that’s what I programmed it for and it reads 1mph faster than gps.....I probably could correct it by entering 32.75 but haven’t tried yet.

Sponsored