ACME vs American/Stehl - turning explanations needed

[Baja_Man]

Hello all--
In a previous post I asked for input on a few different dollies.

Now I need assistance in understanding the differences in how they turn.

The ACME is rigid and uses the towed vehicles steering to make right and left hand turns. Steering wheel is left UNLOCKED. Not sure of the physics behind this and if the turning causes stresses on the towed vehicles suspension, body, chassis, steering, etc. Since the turning is not the same as if the towed vehicles wheels/tires were on ground turning, it seems as though there are different physics going on that I do not fully understand.

The American/Stehls and other dollies use a swivel platform whereby the towed vehicles wheels are strapped down and steering wheel is LOCKED. When turning under tow, the platforms swivel and the vehicles steering never moves. Not sure what actually swivels and could not find any videos or pics showing how this works. Again, the physics of this type of dolly are also not clear to me.

Seems that most dollies use a swivel platform and the ACME may be the only one using a rigid frame with no swiveling, relying on towed vehicles steering to be what steers dolly.

According to American: the ACME puts undue stress on the towed vehicles front suspension, body, chassis, etc. Tires also wear very fast, are small in size (10") and difficult to find replacements. LED lights are expensive to replace (they tend to break as all others from kids, bicycles hitting them, storage accidents, etc.... where American lights are easily found at Walmart and much less expensive). And finally, the surge brakes experience quick failure from all of the debris tossed at them from being towed behind motor home (I am assuming exposed calipers vs enclosed drums)

So, what gives with all of this?

Swivel or no swivel AND why yes or no to each style?

[mowermech]

I do not believe the ACME videos. SOMETHING under the vehicle is twisting to make the steering wheel turn. The vehicle wheels are firmly tied down, they are NOT steering. Yet, something is making the steering wheel turn. To me, based on a lifetime working as a mechanic, that means something is twisting that was not meant to twist. Therefore, I would never buy an ACME tow dolly, or any other with similar construction.
I want a dolly that steers, either with a swivel pan (like the American Tow Dolly), or with king pin steering (like the DEMCO Kar Kaddy).
Also, it is worthy of note that the American dolly is delivered right to your door, with no additional shipping charges!
Yes, the center bolt is the swivel point. That is a very hefty bolt! I have never heard of a swivel bolt failure on any swivel pan dolly.

EDIT: Just as a point of reference, I towed a Chrysler PT Cruiser convertible on a Kar Kaddy dolly. It worked great, all the way from Montana to Georgia and back. But, it had no brakes, so I sold it. That was an INCREDIBLY stupid thing to do! I definitely will get another one, and I do not care whether it has brakes or not!

[RJsfishin]

Picture it the same as towing towing 4 down w/ the steering wheel tied in center position, because that's "almost" the same thing. And that works too. We did that years ago when many vehicles would not track well. And even tire wear was hardly unnoticeable. The only difference, a rigid frame dolly is more forgiving, in that all of the movement is not restricted to the tires slipping, as in 4 down. W/ the rigid frame dolly, leaving the steering unlocked, everything can move a little, so the whole vehicle/dolly assembly is not completely rigid, as one mite think.
And think about this too ! By Acme using the small diameter tires, the footprint of the small tires on the pavement is smaller, giving less traction, therefore letting them slip over the pavement easier. There was some engineering thought went in to this design. And like the rigid frame idea or not, it does work, and apparently works well.
Having said all that, I would still get a DEMCO,....I used to have one. But it is a heavy dolly, and not cheap.

[Baja_Man]

Pros and cons between American and ACME as I see it:

ACME Pros:
Removable ramps
Lighter than most at 385#
surge disc brakes

Cons:
hard to locate wheels tires


American Pros:

Removable ramps
14" standard wheels tires

Cons:
heavier at 485#
electric brakes

The one item between the two I can not determine is ....

is a rigid, non swiveling dolly, (such as ACME) a pro or con?

Once I can figure this out, I can make my choice!!

[Baja_Man]

If I'm understanding correctly, on swivel type dollies......
the wheel pan assembly which runs from one fender to the other is what is stationary and the tongue underneath swivels left/right as tow vehicle makes its turns.

If this is correct, is the center bolt in the image below, the pivot point? If so, is this one bolt what keeps everything together? If so, that is a lot of accountability for one bolt. That bolt breaks and disaster would strike, correct?

Image is of an American Car Dolly

[RJsfishin]

The big advantage Acme has, is there is no danger of the fenders hitting the vehicle in the turns......because nothing turns.

If you want the very best dolly on the market, get a Demco. It mite still be the only dolly that uses king pin steering like a motorhome. This design also lessens the chance of fender contact in the turns. They twist a little, but not near the movement of a turntable dolly.

[Baja_Man]

ACME is $2150 delivered
American is $1499 delivered

[RJsfishin]

I don't think a person has to be very smart to know that there for sure is more stress on the vehicles suspension, and also on the dolly's frame work, and that the tires are somewhat slipping on the pavement in the turns, but that don't mean it causes any serious problems,.....and apparently doesn't
This has all been hashed over many times, and they work ! And the price really should be a lot cheaper,....they are much cheaper to build w/o the steering built in.

[fpresto]

I have an Acme. It turns fine, there is no more stress on the steering or suspension than there is when you are driving and make a turn. In my mind it is the best in the business.

[gbopp]

Well said Snowman9000.

FWIW, if I was buying a dolly, it would be the Acme.

[Snowman9000]

Regarding what you say are American's criticisms of the Acme, I would say that talk is cheap and most of those points are silly on the face of them.

How is the stress on the car any worse than four down towing?
I do hear the 10" tires wear quickly. But you can buy a lot of tires for the price difference of the swivel dollies versus the Acme. I'm told they are a standard boat trailer size, but in a less common heavy load range.
Arguing against LED trailer lights is stupid. They are common as dirt today.
Toad brakes get the same exposure behind the MH, and I have never heard of it being a problem. Brakes live in a nasty environment anyway.

Just reading that nonsense makes me think American is desperate.

I think the original idea was a swiveling dolly. Then someone realized it wasn't necessary because the car's front tires will swivel as needed. And it's a lot simpler, lighter, cheaper dolly that way.

As to the physics of the movements of each, you might be overthinking it. On a swivel dolly, the dolly tires track as needed, and the car swivels so its rear tires can do the same. On the Acme, the same thing happens. In terms of that tracking, the only difference is what is turning, the swivel pan or the car's steering.

A lot of newer cars don't have a steering lock. If you have one of those and you use a swivel dolly, you'll have to rig and un-rig your own steering lock each time you load and unload.