I think I have read every thread on here on gearing and fuel mileage. I'm looking at ordering a new truck Lariat F350 8 ft box, 4x4,camper package, 18" wheels and a few other goodies. Trading in a 08 F250 V10 with 4.10 gears 5 Star tune running 87 performance for about 150,000 miles rest of the truck is the same as the one I plan on ordering. I pull open trailers occasionally anywhere from 4000 to 9000 lbs and will throw 2500lbs of feed in the bed and drive to south Texas.
All the threads I read everyone posts up numbers running 60 to 65 showing good numbers on mpg I run 75 to 80. I'm planning on ordering with 4.30 just don't won't to kill the mpg's I know slow down but you can get run over here on these freeways in Houston and the speed limit on the highways is 75mph.
As of right now the truck I have numbers on has 4.30 but I can change that when I call to tell them to go ahead and order just don't now if 4.30's or 3.73's are the way to go........sorry to keep beating a dead horse but help a brother out.
If it were me, and I'm going to be dragging around anything that's not in the bed, then it would be 4.30's.
The 4.30's will give you better mileage and less tranny/engine strain when accelerating while towing. And if the trailer isn't aerodynamic, even more so at highway speeds.
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'74 F250 Highboy FE390 deceased! I've been wrong before, I'll be wrong again. Just wait and see. ®
A while back I did a comparison of the two rear ratios for given speeds. I used an online calculator that asked for final drive, tranny ratios and tire diameter (I used 18" stock dia of 33.17")
1st gear @ 20mph 3.73=3002rpm/4.30=3461rpm
2nd gear @ 30mph 3.73=2631rpm/4.30=3033rpm
3rd gear @ 40mph 3.73=2299rpm/4.30=2650rpm
4th gear @ 50mph 3.73=2174rpm/4.30=2506rpm
5th gear @ 60mph 3.73=1951rpm/4.30=2224rpm
6th gear @ 70mph 3.73=1773rpm/4.30=2044rpm
All this shows is rpm @ given speeds and doesn't take into account real world rpm necessary to move a load at the given speeds...it shows that basically the 4.30 diff will run 1 gear higher than the 3.73 at the same speed after 1st gear. You folks can take this fwiw.
Thanks everyone for the comments. Just made the call and ordered the truck.
F350 4x4 crew/c 6.2L 172" wb
Trailer tow pkg
Sony prem audio
5"Chrm cab step
Body side molding
Sure wish they would bring back medium wedgewood blue this is three in a row on grey trucks for me, just don't like the colors much. If this truck is as good as the V10 has been I will be a happy man.
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