Speedometer help

[slongson]

I just recently put 35 inch tires on my truck and of course the speedometer is off. I took it to the dealer and still off by 10%, not sure they even did anything. What I need to know is how many revs per mile this size tire makes so that they can make the appropriate changes. Thanks for any help.

 

[67guzzler]

Somewhere between 595 and 600 I'd guess. It varies by tire. I guessed 601 for my 315's (34. 86" dia. ) and it was perfect per the GPS.



Update: I just looked up the BFG MT tires at their site.



http://www.bfgoodrichtires.com/assets/pdf/mud_terrain_ta_km.pdf



Looks like 598 is the number.



I hope this helps.

 

[Diesel Nut]

What brand tire? Go to the manufatcurers website, should be easy to find. You should be able to find the size of the tire and then the rotations per mile. Not all tires are the same. A 35" tire can be 34. 2-35. 7" or more. Just depends. All that plays into it. Good luck.

 

[Udaloy]

If you would have searched, you would have found these links:



http://www.miata.net/garage/tirecalc.html





http://4x4cyberstore.com/website/tru_speed.html

 

[slongson]

Well I took it back to the dealer and set it to 598, looks like we got it. Thanks for the help.

 

[Matt S]

I just called my dealer to have this done and I'm not certain they knew what I was talking about. What do they have to do to get the speedometer to work with the the 598 number?