AWESOME REFLASH, BUT REQUIRES NEW 150mph SPEEDO

[tdecosta]

Left dealer, got on interstate, moved in to empty left lane with pedal on the floor, quickly passing several vehicles... thinking to myself 'this CTD 325/600 sure accelerates nicely!'. Looked down at speedometer, doing 115 :--) Quick scan of St. Louis landscape - no cops - whew, guess I'll be okay this time, but, what's with my truck thinking it's a hemi 'Cuda?



I originally scheduled dealer visit to do 18-037-04 reflash, but changed my mind (for now) due to concerns noted here @ TDR re: possible loss of power. I decided to wait for pre/post dyno comparisons discussed by other members.

The Dodge dealer was great. I had also asked them to reset the truck's computer to accomodate my new tire size of 285-65-18. They did this without charge, and assured me if I changed my mind on the above TSB, they would be glad to do it for me! (King Dodge, St. Louis, MO).

The BF Goodrich website stated 634 revolutions/mile, which my dealer entered in to their DRB III. My speedometer now reads 83 or 84 when I am doing 60mph! Huh???

So, anybody have anything like this? I looked at the revs/mile number, and it seems reasonable compared to other similar sized tires. Should I ask them to reset back to stock tire size? Did I do something wrong?

 

[ceaman]

yeah the dealer did that to me once too... they changed the tire size the wrong way... . go have it refigured.

 

[klenger]

Now you don't need to get the TSB done. You milage will go through the roof now.



You can use the calculator at http://www.klenger.net/dodge/general-reference/gear-speed-calculator.xls to get a pretty good idea of what the revs/mile should be.

 

[KevinO]

Go to the manufactures sight for the tires they should have a chart. My 315/70r17 are 601 revs a mile. Probably need to hurry and get it redone you are putting more miles on your odometer than you really are.