speedo problem..

[greencummins]

So When I first purchased my truck I re calibrated the speedo for my old 35" tires with a snap on scan tool. I put 285s onto the truck now and re calibrated the speedo back to stock tire count. however the speedo doesnt change.. it is still reading as if it has the 35s on it. I have P pumped the truck since then but I dont see how that would make a difference. Anyone know whats going on? when you plug the truck in the tire count reads as it should just the speedo is still off.

Thanks guys

-Jake

 

[greencummins]

bump anyone??

 

[Drumman]

the 285's are not a stock tire size, so if you told the snap on tool to go back to stock size which would be 245/75/16 or 265/75/16 then the reading would not be right. i think you can put the revs per mile in on the snap on tool of what your tires are and it will read correctly.

 

[greencummins]

the 285's are not a stock tire size, so if you told the snap on tool to go back to stock size which would be 245/75/16 or 265/75/16 then the reading would not be right. i think you can put the revs per mile in on the snap on tool of what your tires are and it will read correctly.

I did manually put in the revs per mile multiple times then test drove and it still is fast. I figured id put the size in for 265s and then the speedo would just be a hair slow but it didint change it... this is really stumping me