Just put the 315's on the truck today. Curious as to what the MPH change is


2005, auto, 342 gears ( I believe)

I was at 70 mph at ~1950 rpm


Anything cheap/free to recalibrate speedo?

 

your gears are 3.73 , speedo is off be about 8 percent , you are really doing about 78 at 1950

 

So where do I need to be, roughly, to get around 70-72 mpg?


PS Thanks for the help.

 

65-66 mph should put you real close.

 

Free falling off a cliff, "to get around 70-72 mpg"

 

yeah, I caught that earlier and failed to change it.

 

2005s can be reset by the *******

 

2005s can be reset by the s tealer

 

It's about 8% off as everryone said. If you want your speedo accurate, the computer can be reset. Tell teh dealer that the speedo needs to be reset to 603. This is the # of revs the tires make per mile. Stock ones are 655 or something.

 

AWESOME guys. Thanks alot for your help. I'll get some pics up soon. It's been raining for 4 days straight. I won't complain though, we were about a foot behind on rain.


Thanks again

 

I put the 305's on mine and checked it with the GPS , at a reading of 60mph on the speedo the garmin says I'm doing 61mph. And my overhead is much more accurate now. I got the GPS after I installed the tires but my assumption is the speedo was off from the day I bought the truck