Dually with 22.5 mpg.
 

I have read this thread.

http://67-72chevytrucks.com/vboard/s...d.php?t=370640

Ever since I saw my first one I kind of wondered how bad the mpg is. I know regular dually's get bad enough, but how bad are they.

I ask because I build stuff to drive everywhere, and parking lot hangouts is not my thing.

Re: Dually with 22.5 mpg.
 

Diesel with electric fans with get you started on good MPG ( not sure how good but better than a gasser) and a 700R with OD instread of the Th350/Th400

Re: Dually with 22.5 mpg.
 

I wondered it they get like 6-8mpg no matter what because the rims are so heavy.

Unless you go diesel, and maybe you could get 10.

Re: Dually with 22.5 mpg.
 

i bet they are had as hell on brakes too!! and wheel bearings!

Re: Dually with 22.5 mpg.
 

22.5 and 24.5 truck rims dont weigh anymore then a steel 16" rim
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Re: Dually with 22.5 mpg.
 

I got 11 hwy when mine was on the road. Q-jet fed 454 w/ a TH400 and 4.11's on 225/75/16's. It was lowered, so I'm sure that helped a little.

Re: Dually with 22.5 mpg.
 

I was a truck driver, and I remember those 22.5's being quite heavy. Where as a 16 steel weighs about 35 pounds.

Re: Dually with 22.5 mpg.
 

i work at a tire shop, and the semis 22.5 and 24.5 are quite a bit heavier than standard rim. even the aluminum mag rims are heavier than a steal 16 rim.

Re: Dually with 22.5 mpg.
 

Your right they are about 60 pounds each for a single 22.5”x8.25” Alcoa rim

Re: Dually with 22.5 mpg.
 

Is that after milling them down for the 1 ton swaps?

Re: Dually with 22.5 mpg.
 

They don't get milled down, 8 lug to 10 lug conversion hubs are used, adding to the weight.


Two goals are required for good mileage, engine load and rpm. That's why lighter cars don't load their engine as much and later on, get smaller engines. The other is rpm, lower rpm, the less revolutions per mile the engine has to make, and the less fuel burned.

The problem is while 22.5s give the engine less rpms to turn, their weigh requires more work to get rolling, so the mgs won't improve much, if any, because the engine is either working too hard or the axle gear ratios are changed making the engine run higher rpms.

Re: Dually with 22.5 mpg.
 

he means milling the .125 off of the so you can use car tires on them

Re: Dually with 22.5 mpg.
 

Ah, right. Forgot that's what some choose to do with 22.5s . . .

Re: Dually with 22.5 mpg.
 

I know how to re-engineer something to get better mpg, and or broader performance. One of the things I would love to do to my truck is a pure mpg build, but I feel it wouldn't get anywhere interesting enough to justify the effort.

So how much does a dually set-up get with 22.5 big rig rims. I have always been interested as to how bad it would be as I can't keep the idea out of my head of converting my truck to a rclb slammed dually.

Re: Dually with 22.5 mpg.
 

As you would know then, it depends on the gear ratio, the engine, the transmission, how it is driven, etc etc.

It's kind of an open-ended question. Could get better mpg, could get worse. Depends on how you build it or what the truck is set up with.

Re: Dually with 22.5 mpg.
 

I know built duallies can get up to 17mpg hwy with normal tires. Maybe they could go a bit more with the new 700 treadwares, and modern suv tires. Yes it will loose most of its hd ability, but it would have the look.

No add an extra 200 or so pounds of rolling weight. Just how bad does it get or can it get. My personal guess is a well built 9-1 454, modern cam, roller everything, 4L80E, and gear it for 2300rpm at 70. Maybe you could touch 10-11 on better days.

Re: Dually with 22.5 mpg.
 

Semi wheels are tires weigh drastically more than 16s. Anyone who has ever done tire work can tell you that.

In my area here, we have a bunch of pipeline welders who run the semi wheels on their dually welding rigs. They are death on brake components and front end components.
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Re: Dually with 22.5 mpg.
 

I have a 67 c20 that I'm making into a dually. Got a roll over cummins dually. Going to take the whole drive train and swap it to my truck. Making an aluminum flat bed. I ordered my 22.5's yesterday for it. Found a semi salvage yard that sold them cheap if anyone wants their details.

And after my swap, 22s, and motor work (100hp injectors, reworked cp3, hopefully efi live) should be 22-24mpg all day.
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