Acme Eze-Tow Functional Design

[Scarab0088]

Kelly and Jerry,

I wouldn't try to turn any dolly by hand under the weight of a loaded car. But when loaded - the tongue of the Eze-Tow can be moved by hand. We do this to check the hitch connection at departure.

And, wanted to add one point that seems to be missed when folks describe "how" the fixed frame dolly and car can turn without the pivot pan. You know that:
1. The dolly tongue pivots at the ball.
2. The car's front tire's pivot at the steering (inverted steering).

There is a second action that is part of the car's steering which contributes to the physics of the turn...the car's wheels and tires pivot on the rotor mounted to the hub at the end of the steering knuckle. Because the rotors are on the end of the hub, that action moves the tire/wheel fore and aft in the turn.

3. This fore on one side/aft on the other action adds to the geometry of the turn allowing the dolly to "twist" in relation to the car into and out of any turn.

Best luck

[ThePowells]

Originally Posted by Scarab0088

Kelly and Jerry,

I wouldn't try to turn any dolly by hand under the weight of a loaded car. But when loaded - the tongue of the Eze-Tow can be moved by hand. We do this to check the hitch connection at departure.

And, wanted to add one point that seems to be missed when folks describe "how" the fixed frame dolly and car can turn without the pivot pan. You know that:
1. The dolly tongue pivots at the ball.
2. The car's front tire's pivot at the steering (inverted steering).

There is a second action that is part of the car's steering which contributes to the physics of the turn...the car's wheels and tires pivot on the rotor mounted to the hub at the end of the steering knuckle. Because the rotors are on the end of the hub, that action moves the tire/wheel fore and aft in the turn.

3. This fore on one side/aft on the other action adds to the geometry of the turn allowing the dolly to "twist" in relation to the car into and out of any turn.

Best luck

Steve, I kinda think we are gonna meet in the middle. I understand what you are saying, and I hope that you understand where I am. I think that what you are describing may help with it, but I don't know that the steering motion would equal the amount of wheelbase change. The combination of the wheels rocking out of the rack plus the steering change may get close.

[ThePowells]

Originally Posted by vettenuts

Raleigh, NC?

You aren’t that far from EZ Tow’s factory. Why not just go there and ask them your questions?

From the tone of the missing post from yesterday, I'd better take my body armor.

[LarryJB]

When I first got my eze-tow, I needed to load on gravel and was having trouble with the ramps wanting to lift up off the dolly. I started a discussion about my problem and eze-tow got snippy with me about some of the ideas I had to solve my problem. I loved that dolly and had nothing but positive things to say about it, but they treated me like I was trying to bash their product. At one point they suggested I should get another brand of dolly if I was so un-happy with theirs. I was never un-happy with the dolly, but was treated like I was by them. I have since sold it and switched to towing 4 down.

[vettenuts]

I have put a lot of miles on my EZE Tow and will be putting more on this year. I have had a few issues but have learned and made minor adjustments to the dolly to better suit my use. I have been considering four down when I replace my current car, but if you look at some of the threads here on iRV2, that isn’t problem free either. Broken tow bars, damaged cars, etc. Everyone needs to select the tow method that will best satisfy their requirements. I currently tow a Chevy Malibu, which is four down capable. However, the car also has a known issue in the transmission that GM subsequently guaranteed for 120K miles, which I have now exceeded. I think four down towing has the potential to trigger that failure and and I am better off dolly towing. Also, most who have had tow bars installed probably don’t look at how the tow bar is installed. Some of the installations really hack up the front end of the car by cutting off metal parts, snipping off baffles and cutting up the grill. Personally, I find that a turn off for four down towing for most cars. There are a few that minimize the required alterations.

[twinboat]

Originally Posted by ThePowells

From the tone of the missing post from yesterday, I'd better take my body armor.

I think I read that post before it disappeared. Not so nice.

A swivel pan dolly steers like an old fashion Red Wagon. The inside tire moves under the wagon, the outside tire moves out and foward of the wagon.

A fixed pan dolly tries to pivot the car at the front tires. If the rear tires were on ice, they would slide the opposite way. Because they at not, the front tires move fore and aft in the straps and steer.

EZtow was offering free replacement tires to owners who had the original type splitting the tread open. Probably due to heavy side loads, in tight turns.

In 4 down towing, the tires are also forced to steer but they are free to move back and foward in there arch. No straps or stops restraining them.

[Brockx]

I had an Acme for a few years and the only problem I ever had was storing the "Dolly"(any Dolly). My MH has a front axle 55 degree turn capability with a 9 foot rear overhang. The car and dolly really takes a ride on a full lock turn. This allows some amazingly tight turns and I used that ability frequently. If I ever went to a Dolly again it would be an ACME.

[Scarab0088]

Originally Posted by ThePowells

Steve, I kinda think we are gonna meet in the middle. I understand what you are saying, and I hope that you understand where I am. I think that what you are describing may help with it, but I don't know that the steering motion would equal the amount of wheelbase change. The combination of the wheels rocking out of the rack plus the steering change may get close.

All I can say is that it is not just close, but does the job as needed for our RV (remember, the turn radius on the end of the RV's overhang).

Safe travels

[ThePowells]

A swivel pan dolly steers like an old fashion Red Wagon. The inside tire moves under the wagon, the outside tire moves out and forward of the wagon.

THANK YOU TWIN BOAT!!! That was exactly the mental image I needed to put forth. Also about the rear tires, that is the same image that I have is a "tailswing with the center of the dolly being the point around which it swings. That is why I want to put one on the dolly and then put the rear tires on those vehicle roll around dollies on a smooth concrete or asphalt surface.

[mdvs]

I have been using the eze tow dolly for almost 4 years. I tow a 2007 Saturn Vue. We live in Michigan and have made trips to NC, Seattle, LA and many trips in between. I picked up my dolly at the factory on the first trip to NC. I would say that these trips have totalled over 15K miles. I take my car into Discount tire for rotation every 6K on the Vue's odometer. They measure the tire tread wear and inspect for uneven wear. If the dolly had affected my suspension or alignment I believe I would have found out about it by now. Discount would have told me about the uneven wear and then try to sell me new tires. I would also say that if the concerns about wear and tear on the eze towdolly to the vehicle suspension were occurring there would be posts galore on irv2 about it. I have not seen any. If I had to buy another dolly today it would be another eze tow.

[rcrevolution]

When I was dolly shopping, I happened upon the eze tow video. The stresses placed on the front suspension are pretty clear in the video. Something has to give. The wheelbase in a turn gets shorter on the inside of the turn. There are 3 designs out there...

(1) The dolly tries to pivot under the car, pulling on the chains and straps and stressing the front suspension. This is how Eze Tow does it.

(2) The dolly pivots under the car on the turn table allowing the wheelbase to change with no stress on the front suspension.

(3) The wheels on the dolly track automatically similar to flat towing a car.

[Scarab0088]

Originally Posted by rcrevolution

When I was dolly shopping...
(1) The dolly tries to pivot under the car, pulling on the chains and straps and stressing the front suspension. This is how Eze Tow does it....

The straps on a fixed frame dolly DO pull the tires into and out of each turn... they call that "inverted steering".
The safety chains DO NOT pull on anything - or at least should not.

This is little different from the forces placed on a flat-tow, where the towbar forces the car's front tires to pivot into and out of turns...also inverted steering.

But with the dolly, the basket straps pull on the whole tire/wheel instead of just the contact patch with the roadway.

Belief is different from performance. You don't have to believe it works - it just does.

Safe travels

[rcrevolution]

Originally Posted by Scarab0088

The safety chains DO NOT pull on anything - or at least should not.

This is little different from the forces placed on a flat-tow, where the towbar forces the car's front tires to pivot into and out of turns...also inverted steering.

The Eze Tow video states to leave the chains loose. The only thing allowing the wheel geometry to change wheel base on the inside of the turn are the wheels pulling on the straps. Once they have pulled to their limit, the force goes to the front suspension. I guess as long as you don't turn beyond the ability of the straps to stretch, you're good. It's simple geometry. Their video made me cringe.

Basically, the dolly wheels are replacing the car front wheels. To track properly and stress free, they need to articulate like the front wheels of the car. The fixed dolly works only because the front suspension is stronger than the tie down straps. The stress applied to the car is still there though.

When you tow 4 down, you are just using the caster in the front suspension to track the same path as the MH. I can turn as sharp as my MH will turn and the toad just happily follows.

[Scarab0088]

Originally Posted by rcrevolution

...The only thing allowing the wheel geometry to change wheel base on the inside of the turn are the wheels pulling on the straps. Once they have pulled to their limit, the force goes to the front suspension...

Folks that DO NOT have and DO NOT use a fixed frame dolly keep insisting the erroneous point above.

The straps do not stretch to allow a turn on a fixed frame dolly and there is very little difference between the car's steering geometry for a car towed on a fixed frame dolly and flat towing.

The car's tires and wheels turn to negotiate any turn = steering is inverted...

...on a flat-tow, the steering caster pulls the the tires into and out of a turn...just the caster. There is no assist to turn the tires = high pressures on the steering.

...on a fixed frame dolly, the tires/wheel are pivoted by the basket straps over the entire wheel. The car's wheels pivot on the end of the steering knuckle and the hub. This causes a fore and aft movement of the car's tires/wheels that allow the dolly to twist under the car and negotiate any turn made by an RV.

This is shown over and over on the vendor's videos. It is not rocket science.

If anyone does not want to accept how a fixed frame dolly works:
*There are many, many dollies made but many, many companies with a pivot pan. But the buyer must accept higher weight of the pivot pan, the add'l maint. in the pivot point and the risk of car door to dolly fender contact in a jack-knife situation (broken pivot pan stop).
*Or the buyer can pay a high premium for a dolly with a steering axle. And those are well over 600lb empty and much more maint due to all the moving parts.

Safe travels