Join Date: Oct 2007
Location: Portland, Oregon
Speed vs. RPM
Took my truck on its first hwy trip, about 300 miles. Looks like about 15 mpg
. I noticed that, compared to my late SD
, this truck seems to be geared lower somehow when cruising in OD
. Going down long grades in the SD
it seemed I could take my foot off the pedal and the truck would roll well on its own, maintaining hwy speeds for some distance without slowing down. In the OBS
I felt like I needed another gear almost and had to keep power on to maintain speed.
On flat windless hwy I would cruise at 60 mph at about 1900 rpm. I'm betting that, like the SD
, the 35's are causing my indicated speed to read about 9% low so I'm probably moving about 65 mph. Do these numbers seem normal for the 3.73 (?) rearend that I think I have?
1996 F350, CC, LB, 4x4, 4" lift, 35" MT's, 4.10, 3" DP, Tymar in.....