Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!

Mileage drop from 65 to 75 mph

  • 1

    Votes: 2 8.3%
  • 2

    Votes: 10 41.7%
  • 3

    Votes: 6 25.0%
  • 4

    Votes: 6 25.0%
1 - 11 of 11 Posts

·
Registered
Joined
·
330 Posts
Discussion Starter · #1 ·
Seems like when I drive 65 I can get 19-21. When I drive 75, it drops to 16-18. Is this similar to what the rest of you have seen?
 

·
The Good Son!
Joined
·
1,966 Posts
Yep, once I go over 70 mph my mileage goes down fast.

Over 70 17-18mpg
under 69 21mpg
 

·
Registered
Joined
·
487 Posts
Heck once im over 65 it goes down quick for me. My economy sweet spot is right about 61 mph. I will get 19 to 21 at that speed but drop to 16 to 18 when going over 70.
 

·
Registered
Joined
·
278 Posts
At 60 MPH I get about 24.5 Mpg

At 69 MPH I get about 23 Mpg

But at 72 MPH I get about 20 Mpg

This is hand calculated but with minamal city driving just set the cruise on a two lane for 60 miles is my test strip. That's why I am leaning towards putting in a 6 Speed kit to get to lower RPM's when on the interstate.
 

·
Registered
Joined
·
384 Posts
this is a great post for me to watch cause around her the highest speed i normally get to travel is like 60-65 and sunday i leave for a trip to Missouri to go fishing and have been wandering what kind of millage i will be getting BUMP
 

·
Registered
Joined
·
330 Posts
Discussion Starter · #6 ·
bumpin the poll for the evening crew.......
 

·
Oh...... Squirrel!
Joined
·
24,083 Posts

·
Registered
Joined
·
69 Posts
My '05 F250 PSD, '06 Dodge Cummins and this '08 are all the same. Best overall mileage at roughly 65. Over 68, it drops considerably. All 3 trucks had/have a 4+mpg difference traveling at 65 versus 72.
 
1 - 11 of 11 Posts
Top