I have a 2000 F-150 with 52000 miles. FIPK, Diablo Chip, Flowmaster exhaust, and shift kit. The truck has the stock tires and wheels, with the stock 3.55 gears. I'm leaning real hard towards 4.10 gears. Just wondering how it will effect my fuel economy? Will the performance differance be real dramatic? Any advice will be appreciated as usual.

 

John McGee
to tell you what many have found who run the tall stock tires would be telling you that you would probably pick up on gas millage. Sounds strange that going to a lower rear end would give better gas millage but guess that just goes to show ya that those stock tires are hurting your millage now. I would love to do the same thing myself but i have 28.5" tall tires so my millage would probaby drop 1-2. And since i haven't done it myself, i can't tell you how much of a difference there'll be in performance but i think it'll be fairly noticable.

justin

 

With gears and fuel economy it depends on your driving style and driving routine... 4.10 gears will net you better gas mileage in the city and slower speeds because it takes "less" (actually the torque is multiplied more) to get the truck moving from a stop to cruising speed. At freeway speeds you may see a decrease in gas mileage because on average the truck will be running at a higher RPM while cruising at a steady speed. Although passing will be easier as the truck will be more centered near the power band...

I personally am keeping my stock tire size (275/60R17 30") but going to alter to 4.10s when my budget allows...