What are the advantages of a Dualie, those pickups with double rear wheels?
My assumption is that it is to increase the hauling capacity of the truck. With more wheels, you can support more load, assuming the tire pressure stays the same. Could you do the same thing with only two tires but double their pressure? I know that’s not practical, but would it accomplish the same thing?
Does it also improve the handling for heavy loads or towing by increasing the rear track?
Also, I assume only two of the four wheels are actually driven, the outside two are just along for the ride, so to speak.
Everything that you said except for this is correct. Both sets of wheels are powered and provide traction. Think about it, they are on the same axle and almost all trucks of this type are rear-wheel drive.
I believe that the biggest advantages of a dually are increased traction (this comes in really handy when you are towing a heavy cattle trailer across a muddy, rutted field), and increased stability when pulling a heavy load. The double tires provide a large footprint which helps counter any directional forces that a heavy trailer puts on it.
Yes, but this depends heavily on the trailer. Boat trailers haul very easily, because even though they may be heavy, they tend to be long and narrow. Pop-up camper trailers (the short ones) are almost square and tend to sway a lot on the highway.
No. Both of the wheels are attached (the outside wheel is bolted to the inside one), and both wheels on each side are driven. They also don’t sink into soft earth as much as a single tire would.
Most light trucks aren’t often used for loads so heavy they really need dual rear tires, but it’s not practical to remove the extra wheels/tires when they aren’t really needed. (that is, if you’re always hauling so much stuff your light truch has to have duals, you should probably get a heavier truck) - MC
Beyond the “footprint” (which is not insignificant), duals have a special property on wet roads that give them more traction. (This was the inspiration for the Aqua Tread tire that had a deep groove in the center of the tread.) The channel created by the side-by-side tires provides an area where the water on the road is drawn in, “sucking” (technical term, here) the tires onto the road.
(The original Aqua Tread was discontinued when it was found that the central groove attracted snow to the point of having no traction, but the road-holding-in-rain characteristic worked.)
No, no, no… All the comments about traction and load are accurate, but the main advantage to having dual rear wheels is that it looks really tough. I mean, what’s the point of having a pickup truck if it isn’t macho?
Ah, the Dually. I once worked as a gofer in a Chevy dealer’s service department, and I lost two hubcaps and a rear wheel well off three of these monsters driving them around a corner through a narrow gate. I’m always careful to give them LOTS of room on the road, especially if they seem new or their drivers are very young.
A friend of mine drives a dualie. He lives on a little-traveled county road. When the snow is deep, and there’s only a pair of tracks through the new snow, he can’t go anywhere. He says the outside wheels on his truck will get stuck every time, trying to plow a new track outside the existing one. It’s possible to get a one-ton pickup with single rear wheels.