"Piggybacking" a car/pickup on the frame of a semi tractor

No one?

Not even any comments or flames? :)

I don't think I have ever seen a car on the back of a semi tractor, but it is quite common to deliver three tractors at a time. The front axle of the towed tractors are bolted to a bracket that has a pivot plate and king-pin that attaches to the fifth wheel, (The hitching thing.) allowing the towed tractors to act as semi trailers. (A semi trailer is a trailer without a front axle and a significant amount of weight is carried by the towing vehicle. A full trailer has a front pivoting axle that bears the weight so the towing vehicle only pulls the load.)

They do this so they can deliver three at a time rather than putting two on a flat bed trailer.

Well the common way is to install a section of auto rack ramps. BUT this is usually done on tractors used to haul mobile homes.

However I don't see why you couldn't weld up a set of rails that would allow this. The problem becomes loading the car. The usual method for the trailer guys is to use slide out ramps that hit the ground, Then they drive the nose up and winch the vehicle the rest of the way.

If this is a one time shot then I would just borrow a tow dolly.

If you will need to do it repeatably then I would make up a frame out of a pair of rails with them hinged at the rear of the frame. Attach a winch so you can pull the car up onto the rails. Use a set of long rams to tilt the ramps up for loading. You should be able to get the rams and ramps right from an old car hauler. Just set them up to clear the 5th wheel when they are down.

I can't even imagine why anyone would want to do such a thing, let alone how!

How about a couple of ramps, and drive the car up onto the frame rails, and strap it down?

Good Luck! Rich

Newp.

-- Not merely an absence of noise, Real Silence begins when a reasonable being withdraws from the noise in order to find peace and order in his inner sanctuary. -- Peter Minard

A sketch maybe?

thanks

gary

Because 1 tractor for power, + 3 tractors on the deck is legally the same as a set of pups, i.e. tractor + 2 x 28' trailers and 1 con gear.

Add a towed vehicle, it becomes an LCV, which is prohibited in many states.

The fact that I would do almost anything to avoid the cattle call associated with flying or, even worse, bus, is no small part of it.

$ is an issue here too, i.e. my VW Jetta TDI gets over

50mpg, and I get to wave and smile at the folks enjoying the dining experience, re: 30,000 ft while stacked like sardines in a winged can:) Not to mention the delightful social experience involved in getting INTO said winged conveyance:(

gary

I'm having a problem visualizing this setup, and Steve seems to be busy.

Can anyone provide enlightement? possibly a sketch, as I do much better than with a description.

thanks

gary

Gary, Just a bit busy Sorry.

What you basically need is a set of car width channels (like you see on car haulers) These get set up with a few cross-members in front and behind the 5th wheel. Then they get hinged at the rear of the frame rails on the tractor. Just about like a dump box would be set up. When they are not in use they would set down on the frame tight. This way the 5th wheel is usable. When you want to load the car on you use the rams to lift the rails up. Use a set of ramps (or a loading dock if available) and winch the car onto the rails. Lower the rails down (use stops to keep the car off the 5th wheel as needed) Lock the car down with some over the tire straps and store the ramps and your all set.

If you are running a twin screw the rails will probably be long enough as is. A short single will be a problem but it can be done. Check out some of the mobile home haulers and you will find some with car racks on them. Those are usually fixed mount though because they use a ball hitch. But with hydraulics and some careful plans you could do the same thing and still have a usable 5th wheel.

I understand keeping the bills paid, just have to remember, internet/usenet is a hobby:)

Saw one of these the other day, unfortunately, going the other way at 70mph. Only thing I really got a decent look at was the trailer axle underneath. Driver tows the "carrier" to next job after removing it from tractor. I've been looking through my video files to see if the camera got a decent shot, but I didn't make a note of the time, and with 2gb of video this may take a while:) As I'll be removing the "carrier" to go on to the next job, It doesn't much matter if the fifth wheel is covered as long as it isn't beating on my oil pan.

"Channels" being say, 2" high x tire width? and couple feet longer than the car?

Lift the front of the "carrier"? I'm guessing so the car doesn't drag its underside on the end of the tractor frame as its being pulled up?

Any suggestions re: ramps, as in locating?

Video for anyone who doesn't have a clue what I'm talking about.

gary

Thoughts, concerns, comments, suggestions welcome!

#1 is intended to be rectangular box tubing, 2 is channel material, inside width slightly bigger than tire width(205mm).

thanks

gary

See you did figure it out... Most of the ones I have seen use a ram on the front end to tilt the deck up in front. This allows the vehicle to clear the frame stubs without bottoming out. Hinge point is usually right at the end of the frame. Most use a Z variation on the channel, the outer section is up while the inner is down. Guides the vehicle but also allows different tire widths. Also is stronger with the ribs going both directions. For loading ramps most use a set of ramps like a car carrier. Or if handy a loading dock makes it easier. Make sure that the entire thing will clear the 5th wheel during any maneuvers. Or make it so you can bolt/pin it together as needed.

Could you describe the ram, mount, etc a bit more? I'm trying not to re-invent the wheel, er, carrier here.

In trying to minimize the complexity as much as possible, I'm thinking the "hinge" just needs to allow the rail to lift in the front, while keeping the rear from sliding sideways on the tractor frame.

The "pin" shown at the right edge of the channel would slip under the lip of the tractor framem and allow the "U" channel to pivot as the front is lifted.

Z?

Planning on a bolt together setup, I'm thinking a 1 piece carrier would be too heavy to lift off the frame alone.

Thoughts regarding 2" x 4" box tubing being appropriate?

thanks

gary

Most of the rams are simple long rams Just rated to lift the ramps with a vehicle on them. For this you could use a scissor lift style unit as well. Would take longer to lift but if a few extra minutes are not a problem an electric screw lift would probably be easier to deal with.

Yep, BUT you also don't want the rear section to slip around or bind while loading. Rear section could be bolted to existing frame holes.

Basically the hinge is nothing but a pin with a welded sleeve on the frame. They look like the old style barn door hinges with a pin and strap.

Yeah, it could be a bear.

Depends on the cars weight.