# live tandem



## Guest (Oct 1, 2001)

Does anyone know how to make a 1 ton dually into a live tandem truck?


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## Alan (Mar 2, 2000)

Apply MONEY! Anything is possible if you throw enough dollars at it, practical is another matter though.


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## 2401 (Feb 3, 2001)

I have seen a (very) few 1-ton duallys with 2 rear axles, although I wasn't able to get a close-up look at them I'm pretty sure the 2'nd axle was a "tag" (non-powered) one.

Are you giving thought to doing this for "something different", or is there a specific application for the truck?

As Alan said, with enough $$$ anything is possible. This would require quite a few $$$ IMO, I'm looking at the axle on MY dually and comparing it to the ones on the Macks I drove for a few years. Problem is going to be getting the power from the lead axle to the rear one - lead axle has a driveshaft coming out of both ends. The lead & rear axles on the "big truck" tandems use different axle housings. Fair bit of custom work here.

Mind you, there's a possibility that this has been before, and there may well be a conversion "kit" of some kind to do this. Putting the Internet search engine to work might be a place to start.

One "con" I can see to doing such a conversion is the increased weight of the additional axle/suspension/drive components. While the carrying capacity will increase (from 4 more tires) the engine/transmission is still going to be the the 1-ton unit. Mind you, you could upgrade that with something bigger too..................

Not trying to bash your idea - just want you to be aware of the scope of what could be involved.


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## Alan (Mar 2, 2000)

I saw such a conversion in an off road magazine a few years back. It was done on a Jeep and they had somehow rigged two outputs on the transfer case and offset the differentials to allow the twin shafts. Somehow they made allowance for the axles to oscillate with the shaft to the rear one somehow clearing the front one. Looked like a big pile of money climbing the rocks.


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## 2401 (Feb 3, 2001)

Man, that sounds complicated!

Thinking a little more about my truckin' days, I recall the switch on the dash marked "Inter-Axle Differential Lock" or words to that effect. Similar to a locker in a 4x4 pickup axle, it was there to get power to all the wheels if needed, such as on a snowy parking lot. For normal driving, it stayed in the "disengaged" position.

I mention this because, if additional traction is one reason for the "live tandem" conversion, just having another "diffy" and pair of wheels back there may not help as much as you think!


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## CT18fireman (Nov 30, 2000)

I saw that article. I have also seen jobs done using semi-truck axles. Most of these are done for off road. A tag axle could be installed but would not really help a one ton much. The weight of the assemble would just about outweigh any increase in possible gvwr. Legally the cargo weight would not be able to be changed as far as I understand DOT laws. Also as far as plowing. In terms of how most one tons are used trying to turn with two sets of rear powered axles might cause a bind up when turning sharp. For a road plower it would be fine but as for a lot or driveway truck I cannot see any benefit.


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## Guest (Oct 5, 2001)

Thanks to all for such a quick response to this ? I'm building a 1962 B Model and putting it on a 1976 1 Ton chassis. So it really isn't a big deal to have a live axle. don't need the extra project but if any one has good ideas as far as mounting a tag please advise because that much I will do. thanks again Jamr


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## 2401 (Feb 3, 2001)

Is this truck being built for "show" or for "go"? (NOT being a smart - *** here, just wondering  )

Because that will make a difference in how best to mount the tag.

If "show", easiest way would be another set of springs/shackles. It will always be "down", and would look quite similar to a tandem until you got up close & looked.

If "go", you'll probably want to have some means of raising it when not in use, particularly in the winter. Having an unpowered axle right next to your drive axle will tend to transfer weight off your drive wheels, generally at inopportune times.


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## Guest (Oct 6, 2001)

*live tadem*

This truck is kinda going to be show and light duty with an aluminum flat bed and a hoist. I was thinking in the line of maybe using a four link set up with coil over shocks like the street rods use. 
Jim


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## steveair (Feb 24, 2000)

Hello,

At the airport, there was a f350 super duty with a second axle used on the ramps. It was a boom truck, mainly used for deicing aircraft. I guess they put the second axle on to support all the weight of the boom and liquid storage and also for stabilization when the boom was out.

Not sure if it was a 'live' axle, but what you are talking about has definitely been done before. Thought I had some pics somewhere, but will have to look hard.

steve


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## thelawnguy (May 20, 2001)

Dodge made a tandem axle show truck, basically what they did is take the 4 trailing arm front suspension and put it in the back. According to reports at the time it worked very well, but the issue of tire scrubbing during turns may be a big negative.


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## 2401 (Feb 3, 2001)

If the additional axle is located close to the drive axle, tire scrub shouldn't be too much of an issue - no worse than on many trailers.

It becomes more of a problem on l-o-n-g spreads such as the 10' spread on the flatbed trailers I used to pull. These did NOT like sharp turns, especially loaded.

Here in Ontario, lift axles are very common. Generally the drivers will raise 'em when making a corner, then put them back down again. Down on your side of the border, I see more & more trucks with multiple axles between the steer & drive positions. These are always down, but are self-steering/self centering (basically spring-loaded tie rods)


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## thegrasscatcher (Jan 22, 2002)

I know this thread is old, but I did the exact thing (tandem axle) to my 78 F-150. You simply take an older divorced style transfer case (mine was from a 75 F-250) and turn it backwards. Feed the rear output shaft off the first transfer case into the rear output shaft of the second transfer case. Then on the second case, you have the Front Output yoke and the Input Yoke sitting there. Use the input shaft yoke to power the axle that you want live all the time, and the Front Output shaft yoke to power the axle that you want to lock and unlock. I ran a rod and cable to a second shifter in the floor to select whether I wanted 2 or 4 or 6 wheel drive.

Wally


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