another mpg problem
Senior User
Joined: Jan 2001
Posts: 416
Likes: 0
another mpg problem
After reading all these posts I noticed that no-one mentioned recalibrating the speedometer for the bigger tires. I don't know if it is imporant when using a manual trans but it does make a difference with the auto trans. Check this site out for threads on recalibrating the speedo, after all, it is electric and is run by a sensor in the rear differential which, when running bigger (taller) tires, will be turning slower. Running bigger tires is sort of like running slightly up hill all the time and you do have to step harder on the gas pedal when you run up hill, don't you?
Senior User
Joined: Apr 2003
Posts: 376
Likes: 0
From: Wanatah In,
another mpg problem
I tried a 160 degree stat and the mileage went down horribly, also when I replaced my 30x9.50 tires with the 235's my mileage went down a little. You can recalibrate your speedo to compensate for the tire size.
Senior User
Joined: Jun 2003
Posts: 222
Likes: 0
From: Cumming, GA
another mpg problem
Call me a nerd, but I have a log of every fill-up since my truck was bought 10 years ago. I used excel to plot points that averaged the mileage over the past 25 fillups. The truck began its life at 15 mpg, dropped to about 14 at 75k, then at 75k it dropped to 12 when dad put on 31 inch tires (still with the 3.55). Since then it has stayed at about 12, now at 150k. Somewhere there, probably about 125k, we put on a 4.10 LSD, but I cannot see any noticeable mileage difference in the curve. But with the 4.10 and 31's, the ratio is about the same as 3.55 with 29's (maybe a little bit lower, yielding slightly higher RPMs).
Thread
Thread Starter
Forum
Replies
Last Post
giantslayer
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
4
Nov 7, 2011 08:54 PM
