I know we are all in the same terrible situation with the ridiculous price to fuel our rigs. I am now wondering if it makes any sense change my ZF5 rear end gears from the 4:10 ratio to 3:73 or even a 3:55 ratio. Or is it plausible to do the gear splitter on the transmission. Will any of this is head banging substantially increase mpg by 4-6 mpg and if so, at what point (number of miles driven) will or could I hope to break even on the upfront cost. I don't see fuel cost coming back down anytime soon.
My driving for the Spring / Summer looks like this - East coast and back in June or early July, finishing up with a stop at the NO BS OBS gathering in Salem OR in mid August. Or do I just say maybe next year?

I'm sure I'm not the first to think of this but I'm hoping some of you gurus out there who have more knowledge than I do, have noodled this through and can provide some insight. Your thoughts / ideas are appreciated. Stuck in the California diesel wilderness.

 

mine gets 19 MPG around town and 14 towing 10k gooseneck

The power curve cross at your crusie speed is what to aim for.

Gear vendor and a drive shaft can cost more that the fuel that you might save.

Bigger tires can help change ratio and keeping them aired up can help some.

Re gear can cost 300-500 per axle plus labor

 

Thanks for the cost info on gear enders. Not going in that direction anytime soon. I may look into changing the rest end gears as $500+/-?
I’m running 215/85/16 tires E rated pressure at 65lbs. Getting 19 on long drives staying at about 63 mph. Just hoping to pick up some time when speed limit is 75-80 in states east of California. Looks like it may not be economically feasible. Darn!

 

When I have nothing to haul in the bed or hook anything to a ball, then I'm in my 4 cylinder Honda Accord, getting 30+ mpg........... With the only exception of taking the T-Bird out for a joy ride of course.

Point being, you're looking for crumbs when you should be looking for a hunk of steak. It doesn't take too long to eat up the offset cost of the beater to moderate level 4 cly car expenses; purchase, tag, insurance, maintenance etc. of swilling all that fuel up, getting under 20mpg either (and lets be very honest with ourselves, which is absolutely pathetic in this day and age). The little Civic's can yeild 40mpg+ plus now too.

I'd love to drive this as my daily driver;



But there's something I desire far more; To be able to retire with dignity (perhaps even with a little extra comfort) someday. Priorities.

 

Just one forum know-it-all's opinion here:

Regearing, adding overdrive, or otherwise spending a ton of money and time modifying a vehicle to achieve higher fuel economy is almost always a fool's errand. That being said, when fuel prices go up (substantially in this case) a lot of people begin to find ways to save money on fuel regardless of the cost/labor involved. They also tend to start to complain about the fuel economy their vehicle achieves even when there's nothing wrong with it and the MPG numbers were perfectly acceptable when fuel was, say, $2.00/gallon cheaper. Being in the automotive technician field for 26 years, I have heard about every gas price hike since Clinton was perjuring himself.

EDIT:
One thing I will mention casually as it's only based on one vehicle over tens of thousands of miles. I owned a 1984 Bronco II in high school with the 2.8L and a 5-speed. I drive the exact same route now as I did 32 years ago - all interstate - and I drive the same way - slow and steady. That vehicle got better fuel economy in 4th at much higher RPM than it could ever hope to get in 5th gear (and I tried lots of times both ways) simply because that poor rig was too gutless to get out of its own way and was working way too hard just to maintain speed in 5th. I guess the idea here is that it's not simply RPM at speed that determines fuel economy; how far your right foot is in it dictates a lot. Stop and go driving will cause the engine harder to get to speed (supposing the rate of acceleration is the same from one gearset to another) with numerically lower gearing too.

It's your vehicle and you can do what you want but know that it will take time to recoup the cost of major mechanical modifications - money that will be spent over a long time period instead of all hundreds/thousands at once. It obviously will take less time to offset the cost if you're traveling thousands of miles in a month vs. just a few thousand a year.

I'm with the previous poster. I save a boatload of money every year by seasonally driving decent sedans (one in the winter - 1991 Olds Calais with 312K on it and a 2007 Taurus with the Vulcan 3.0L in the summer) that get 30MPG highway (I don't drive in town much at all and have a long commute) that burn cheaper fuel. I don't LIKE driving cars.....but my wallet likes me to drive them......so I drive the pickups on occasion just to remind myself that I'm alive.

On the subject of your thread title.....

At least something is going there. The other thing.....well..........

 

If you are getting about 19 mpg then you are about at the thresh hold for the truck. I think I saw 21 once or twice on long drives on the interstate and I have 3.55 gears. 2 mpg on an ideal trip is not worth the money to change the gear ratio.

as mentioned, keep it in tip top form to get the most out of it and get a cheap beater to keep costs down. You can buy a heater cheaper than you can add a gear vendors kit.

 

Thanks for the replies. Likewise I have another vehicle as my daily driver a 2005 4 Runner. Generally, I save the truck for the long hauls mainly because I just like driving my truck. It’s just the higher price for fuel has me curtailing some drives. There’s no getting around it - our trucks are just awesome and cool to boot.

 

I'm very hesitant to hook up to the 5er this year at a average of 7.7 mpg. My wife just wants to take the VW Beetle TDI that gets 40 mpg at 80 mph but in my opinion, it doesn't have enough room to pack stuff for our annual trip. What to do, what to do? I love the 5er but..................

 

 

These engines are not very efficient and the truck is shaped like a box. Taller gears may help, but if 4x4 would require more effort and cash. I think I squeezed out 16 from my dually once going 65mph and about 10 in town. Ext cab, manual.

South Texas is about $3.50 for 87RUG and about $4.75 for No 2 in town, truck stops (Loves, Flying J, etc) were about $5.20 on I45

My dually is parked anyway as stuck in yard same with my 300SD, no need for either.

Find some beater and rock it. I have two dork Hondas that are good for putting around. FWD GM with the 3800 rock. Even the earlier A bodies

 

Last fill up here in Arkansas was $4.90gal. I don't tow much with the 7.3. Loaded 4K trailer with the 6.6 im getting 16mpg average. lots of grades to deal with. Sheep need to eat.

 

Before long I'll be taking mine out of the garage from its winter rest to wash it and put it back in because I can't afford to drive it. Im glad I have my 4 cylinder ranger. It's not great but will get 25+ if I drive 55-60. Drops in a hurry the faster I go as its pretty underpowered.

 

My late father used to talk about Mobil Economy runs when he worked for them. My "economy vehicle" is an old 87 Subaru 4wd wagon, lifted 4" and converted to 6 x 5.5" lug wheels. Best mileage with that combo on an anemic 1.8L flat four is 22 mpg. I built a Frankenmotor 2.5L that will double the HP & torque and should make better mileage behind the 5 speed stick.
Happy Easter everyone,

Mobilgas Economy Runs

 

I paid 5.29 yesterday so I could drive mine to our car clubs cruise in ..I won't be driving mine much at all other than pulling boat or camper.
I'm curious to see how my 76 f150 390/c6 does with the gear vendors...

 

Filled up yesterday in California, $7.49 per gallon. I filled over 26 gallons between the two tanks.

About 2 months ago I pulled my trailer to my friends property over 100 miles away. Waited to fill up and haven't driven since then. What a mistake to wait to fill up. Should have done it a month ago.