Pusher Trailer: Legal Issues?

[cRiPpLe_rOoStEr]

Would the objection toward a truck axle into a trailer be specific to used parts or is it also a matter of concern if you buy a brand-new axle? But anyway, I have never seen anything regarding that matter.

[freebeard]

Here I am searching for pusher trailer information before posting... and apparently I already asked about it a few years ago.

It's happened to me, but I wasn't OP.

It's a timely question what with the EV tow questions floating around. I suspect any regulation would be aimed at trailers made from the back half of a pickup. They're sub-optimal. Don't look like one. Not getting pulled over is half the battle.

Why do you ask? Part in hand? What's the use case (gross weight, etc.)?

Here's the rear axle I have on the bench*, but it's intended for a Baja Bug instead of a trailer. It would be sweet in an Airstream Bambi.



* 98lb, 68hp, 10,000rpm. It eats 250-400V.

[cray54]

Originally Posted by cRiPpLe_rOoStEr

Would the objection toward a truck axle into a trailer be specific to used parts or is it also a matter of concern if you buy a brand-new axle? But anyway, I have never seen anything regarding that matter.

When I first started thinking about it, I briefly searched regulations and [somehow] found restrictions on using truck axles. A few years later when I decided to look into it again, I didn't find anything related. I was under the impression it was because it was a driven axle, but I have no idea where or what I actually read at the time.

[cray54]

Originally Posted by freebeard

...I suspect any regulation would be aimed at trailers made from the back half of a pickup. They're sub-optimal. Don't look like one. Not getting pulled over is half the battle...

While I agree, my situation is likely to be similar to "trailer made from back half of pickup truck", which is why I'm trying to nail it down.

Originally Posted by freebeard

Why do you ask? Part in hand? What's the use case (gross weight, etc.)?

I'm just starting the design effort; and want to see if there are restrictions that need to be considered. I'm probably looking at something that is in the 2500 lb range.

[freebeard]

While I agree, my situation is likely to be similar to "trailer made from back half of pickup truck"...
....
I'm just starting the design effort...probably looking at something that is in the 2500 lb range.

The thread title is Pusher Trailer: Legal Issues?. And "I was under the impression it was because it was a driven axle, but I have no idea where or what I actually read at the time."

So I'm supposing the intention is to drive the pickup truck axle. If you put a pickup truck bed on a trailer frame with a properly centered axle with trailer fenders, it wouldn't remind me of a chopped-up truck.

How do you propose to power the truck axle? Electric? The item I showed in Permalink #12 is a subframe out of an SUV (minus the rear mount and a crossbar ). You could get a similar item from the newer RAV4 and possibly others, with suspension and road wheels. Weld a trailer hitch directly to the subframe and add a battery bank and leave 1/4 ton for cargo capacity.

[oil pan 4]

Everything is against the law in Massachusetts. I wouldn't try it there.

[Tahoe_Hybrid]

Originally Posted by cray54

I have had a hard time finding information about the legalities associated with building a pusher trailer. I have read that some states do not allow re-purposed truck axles on trailers, but have not seen the actual sources of such information.

I'm specifically interested in Massachusetts (since that's where I live), but I am also interested in other states. I'd like to be able to take my trailer on out-of-state trips.

Are there laws preventing such trailers from being used on the road?

Thanks - Chris

Honestly push trailers are a bad idea
unless these are hitch only with no ball??(bad idea to have a powered device on a pivot point) because of torque steer.


you may also need a independent rear suspension.
a solid rear axle, so when the left tire would bounce on a bump the right tire would tilt out and ride along its edge.

that could be a issue with bumps in the road and cause the torque steer

If you have like a SUV

asymmetrical AWD system would do

[cray54]

Originally Posted by Tahoe_Hybrid

Honestly push trailers are a bad idea
unless these are hitch only with no ball??(bad idea to have a powered device on a pivot point) because of torque steer.


you may also need a independent rear suspension.
a solid rear axle, so when the left tire would bounce on a bump the right tire would tilt out and ride along its edge.

that could be a issue with bumps in the road and cause the torque steer

If you have like a SUV

asymmetrical AWD system would do

I'm not quite sure I follow. I can't picture how the concept of torque steer (usually used to describe steering inputs during acceleration on an FWD car) would be applied to a solid rear axle on a trailer.

I think, like most design ideas, the parameters need to be set appropriately. When towing and slowing down, the trailer is loading the tow vehicle in a similar way to a pusher trailer. We don't see them jackknifing regularly, because the loads are reasonable. I don't think I share your primary concerns, but I think that is because I'm picturing much lighter loading than you may be picturing.

[cray54]

Originally Posted by freebeard

The thread title is Pusher Trailer: Legal Issues?. And "I was under the impression it was because it was a driven axle, but I have no idea where or what I actually read at the time."

So I'm supposing the intention is to drive the pickup truck axle. If you put a pickup truck bed on a trailer frame with a properly centered axle with trailer fenders, it wouldn't remind me of a chopped-up truck.

How do you propose to power the truck axle? Electric? The item I showed in Permalink #12 is a subframe out of an SUV (minus the rear mount and a crossbar ). You could get a similar item from the newer RAV4 and possibly others, with suspension and road wheels. Weld a trailer hitch directly to the subframe and add a battery bank and leave 1/4 ton for cargo capacity.

Yes, I'm planning to drive the axle, and I'm picturing the most reasonable axle to use for my configuration is a straight axle. As I've read through the replies, I think finding an appropriately sized manufactured trailer is the best path. Then, swap in a solid axle that matches, and work on a modified trailer instead of a scratch-built trailer.

In this case, my goal is to push a vehicle, but not with a specific power source in mind. This first round will be more for testing the concept. I expect the easiest way to control the load is to drive the system with an electric motor, but the least expensive way will be with a small gas engine. I'll be starting the design effort soon, and will see if any nice electric power options come up on the used market.

[Tahoe_Hybrid]

Originally Posted by cray54

I'm not quite sure I follow. I can't picture how the concept of torque steer (usually used to describe steering inputs during acceleration on an FWD car) would be applied to a solid rear axle on a trailer.

I think, like most design ideas, the parameters need to be set appropriately. When towing and slowing down, the trailer is loading the tow vehicle in a similar way to a pusher trailer. We don't see them jackknifing regularly, because the loads are reasonable. I don't think I share your primary concerns, but I think that is because I'm picturing much lighter loading than you may be picturing.

torque steer happens when drive wheels turn the car watch any Ford Mustang Crash Compilation and you will get the idea what that is

the first one demos that issue you can hear one rear wheel spin and the other has traction he quickly lost control and steered into the wall



on the tahoe i have it does not have torque steer but I can make the rear end slide out (drift)if i need to I have done it at low speed to prevent getting in an accident ( stupid pos tried showing off and nearly tboned me as he under steered on a dual left turn I was in the right-left turn lane )
close only by a couple of inches..

https://www.youtube.com/watch?v=MhyLAHiNW9g

also this is a video of unstable trailers with a Ball trailer

https://www.youtube.com/watch?v=Z7Kfl97b57s