Convert Toyota pickup to dually?

[IHDiesel73L]

I have a 1991 Toyota pickup that I am building up as an off road firewood hauler. Basically a truck that can be taken down tight, and sometimes very rough trails, pickup a heavy load, and get back out again. This is the truck as it is now:

Mild lift, 32" D-rated mud terrains, 5 speed/4WD/22RE 4 cylinder, stock 4.10 gearing. I've already upgraded the front brakes to larger T-100 discs and calipers in order to help stop it when fully loaded. The first order of business will be to spool the rearend and swap out the 4.10s for 5.71s front and rear which will allow me to get heavy loads going with ease with the 22RE. The truck will see very little if any highway driving so the super low gears will not be an issue there. I am also converting the rear axle from a semi floater with drum brakes to a full floater (via a kit from Front Range Off Road) with disc brakes in order to up the carrying capacity of the rear axle, and to have more stopping power. Also in the works is a flatbed with removable stake sides-since I'm going with a flatbed anyway, I thought it would be a neat idea to make it a dually as well. Of course, it's a 6 lug 5.5" bolt circle rearend and there are no dually wheels available for it, but in searching on the internet, I found this picture of an adapter:

As far as I can tell it was made by a company (this was a full size Jeep pickup BTW) out in Minnesota that has long gone out of business. However, I would imagine that any good machine shop could fab something up-for a price of course Anyway, just wondering if anyone else has tried something similar and if so how they did it?

 

[bcp]

In years past, I've seen lots of Toyota pickup based small motorhomes with duals. I would be checking wrecking yards.

http://portland.craigslist.org/clk/cto/3231484307.html

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[IHDiesel73L]

In years past, I've seen lots of Toyota pickup based small motorhomes with duals. I would be checking wrecking yards.

87 toyota motorhome

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The problem with those is that they have a weird (6x7.25") bolt circle that severely limits your wheel choices to OE 14" Toyota wheels.

 

[BHD]

get a dully rear end with the proper gears if your going to swap it out, and use dully wheels for that axle,

measure for clearances of the dully tires, turned in, and make sure nothing is going to rub,

(I really doubt if you really need duel tires) a standard 3/4 ton pickup axle may work, (the brakes are not as wide as with a one axle) but I have never tried to bolt up a duel wheel on a 3/4 ton axle,

depending on the axle one can many times find like new take offs on Ebay for rims, (the coined rims like the old ford and dodge are hard to find in 16" most are 16.5" and I suggest you stay away from them),

you would have to match the front tires or use the size difference to match the ratio difference if there is any, as I was under the impression the ford and Chevy was 4.11 not 4.10 do not know if that would make a problem or not.

( I have not measured but I was under the impression that the one ton axles dully were wider than the one for single tires) but your pickup is narrow)

on my larger trucks with dully rear wheels the front wheel is in line with the inside rear duel, but on the one tons the front wheel is splits the tracks of the real wheels, or is in the middle of the rear tires,
(I sure both the one tones are like that), and the one 1/2 ton ford, and the GMC 2 1/2 tone line up,

 

[bcp]

The problem with those is that they have a weird (6x7.25") bolt circle that severely limits your wheel choices to OE 14" Toyota wheels.

I thought those nuts looked kind of small or wide spread.

Bruce

 

[AndyUK]

Hi
could you drill another set of wheels to the toyota stud patten, of course l dont know what is common over there with wheels but here the good old ford transit is fitted with dual wheels and very cheap, pcd is 6 on 170mm and you need 6 on 140mm, would be pretty easy to rig up a jig to drill them

should manage to get another 6 holes inbetween those already there
is this how your duallys look ?

 

[bucktaker]

if you are going to be mucking around in the woods why do you want a dually it will reduce your traction PSI and make getting stuck easier. Try upgrading your tires and adding air bags fwiw

 

[Shenandoah]

As was mentioned, duallies will reduce your traction PSI, but should help with floatation. On hard surfaces they should increase your braking ability versus soft surfaces where you'll want 'bite'.

Something else to consider is to simply find a boneyard rearend of any brand that has the spring load plus the dual wheels you're looking for. I put a 9 inch Ford rearend underneath my 39 Chevy and the Chevy doesn't even know the difference, if you know what I mean.

If this is an off-road only who cares if the wheels on the front don't match the rears.

Also consider a brake master cylinder upgrade (boneyard, maybe) to match the heavier demands (if any) of the swap. You'll need reservoir capacity to match the set up.

Sounds like a fun project...

 

[Car Doc]

I am with bcp they also made 1 ton pickups back then besides the mini motor home chassis cabs so there could be junk yard parts available. I imagine a spacer like what you found could be easily built also and just use stock wheels since its non hiway it wouldn't have to be safe.

 

[PoorPlowboy]

Those adapters are dangerous on hard surface roads at highway speeds. They aren't concentric, and not easily made so that they will be concentric when bolted down. Vibration and abnormal tire wear is usually the result. Isuzu or Toyota should have a bolt on true dually axle that will work.

 

[swick1]

I'd look at swapping to a 3/4 ton rear axle with the right ratio to match the front and putting tractor front tires on it. I'd do this front and rear. I can fill up my ram 2500 over the bed rails (8 ft bed) and it still drives fine. Single rear wheel.

I just had 4000lbs in it the other day, but it was palletized and forward of the rear axle.

 

[pat32rf]

If you are going to all that trouble, why spool the rear end. A locker of some type will give better traction up until one wheel breaks loose on a straight pull. On a turn the spool forces one wheel to loose traction...
I'd go with a WIDE(12") aggresive 4x4 tire instead of duals as well. Rims will be easier to find and still be capable of carrying 6000lbs on the rear axle.

 

[bcp]

..off road firewood hauler. Basically a truck that can be taken down tight ...trails,

Duals and tight trails don't play well together.

Bruce

 

[94BULLITT]

There is no way I would run a spool on the highway, my wood truck has one and it's offroad only. It is hard to steer.

 

[Raspy]

You're begging for a broken axle by mounting another wheel way outside like that and then putting a heavy load in the truck. The bending stress on the axle is extreme. Dual rear wheels should be mounted on full floater axles where the load is transferred to the axle housing instead of the driving axle. That's the way manufacturer's do it and have done it for a very long time. Those dually setups on semi float rear axles are just plain dangerous. Besides that, there is no advantage in traction that I've seen.

If you want a dually, get a full floater Dana or AAM axle from a 1 ton truck and use that. Then, the sky is the limit on the load you can carry. If you insist on stressing your Toyota axle that way, think of this thread as you walk home and your truck is sitting with a broken axle.

Sometimes it pays to be a little more fair with your machinery.

 

[IHDiesel73L]

You're begging for a broken axle by mounting another wheel way outside like that and then putting a heavy load in the truck. The bending stress on the axle is extreme. Dual rear wheels should be mounted on full floater axles

A full floater was part of the plan. If you look back at the OP you'll see where I reference a conversion kit that uses front hubs from a '79-'84 SFA truck to turn the rear semi-floater into a full. Still, given the other reasons that duals might not work, I think I might forgoe them and just make sure I have good tires on the full floating rear.

 

[Raspy]

Oh yeah, I missed that that was a true full floater.

 

[Arkaybee]

My wood truck is a '72 Ford Courier (by Mazda) 2 WD with stock 4.11 gearing and standard tires. I have loaded it to the top of the cab (really made it squat) and it would, almost at idle, walk out of the woods through mudholes over log filled ditches sinking through the soft mud on top to contact the firmer soil below and never got it stuck here in N.W. Louisiana. In one really bad area I did wait until a cold spell when there was a frozen crust on the ground to make a haul out of there but, again, no problems. The worst disadvantage/problem is the light front-end with minimal steering contact at times--CAUTIOUS DRIVING! That Ford Courier is a stout little wood hauler--takes to narrow trails too. Always wished for a flatbed on it though. One time in Florida I hauled a full pallet of hybrid bermuda sod for about 50 miles and that was some light steering.

Arkaybee

 

[Ed of all trades]

If you are looking to make a truck that will go on TIGHT trails, why are you making it wider? A good set of wide mudders with lots of bite and heavy ply sidewalls will carry more than the truck can safely carry. If you think it looks cool then by all means go ahead but I really believe you will be making the truck less of a woods truck instead of more. I am not just guessing I have spent many years driving trucks in the woods, cutting firewood, pulpwood, and logs. :2cents:

 

[kubotakid USA]

Single muders are the best for gettin in,.And gettin back out..Thats why all u see on cement trucks is the big singles. Duals load up with mud, between the tires and spin out. They float better, but wont pull when u get into mud.

kubotakid USA