Power assist tow dollies/trailer mover, are typically built with either an AC or DC electric motor, gas motor, or old fashioned hand crank muscle power. They come in a variety of shapes and sizes. Some are designed with a single drive tire, while others have 2 or more. Power assist dollies/trailer movers are the most convenient way of moving trailers and other equipment in and out of driveways, garages, backyards and retail showrooms. They are very useful for parking in locations where obstacles and tight turns are impossible to navigate otherwise.
What type of electric motors are used?
DC Winch Motors
Some powered assist tow dolly/trailer mover manufactures have chose to use DC electric winch motors because they are compact, cheap and easy to replace. The major problems with using a winch motor is that they are NOT designed to operate for long run periods, known to quickly overheat and require frequent cool down periods, to ensure no internal damage to the motor. They are known to move at slow speed because of their large gear ratio, typically traveling less than 1/2 feet per second or less.
AC Electric Motors
This style of motor requires you to connect to a long extension cord and drag it behind you, causing a possible tripping hazard and electrocution hazard when near large puddles etc. Most of these are very large in size, and most do not use proper gearing. They are not meant to be used on hills or grades of any size unless you have an electric brake system on your trailer. Many of them are slow because they need maximum torque from an undersized motor (about 15 feet per minute.)
Some motors use a planetary gear transmission. Cheaply made transmissions are typically very noisy (some refer it as an awful grinding chattering noise) and have a very short life span (normally last for 2-3 years under normal use.) Some have the ability to allow the operator to place the transmission in and out of gear. This enables the power tow dolly to go into a so called "free wheel mode." Free wheeling enables the operator the ability to manually push or pull the tow dolly with no power assistance. This is good if your battery is dead or if you have a long distance to manually push the tow dolly.
Simple ON/OFF Switches
The typical rocker, or momentary switch only provides direct full power to the dolly. Simply put, as soon as you hit the switch you'll have full unmanageable torque coming from your tow dolly. Releasing the switch the tow dolly/trolly comes to a complete stop causing a large jerking motion to the trailer. This is very hard on the dollies/trollies transmission, and can cause unwanted stress on the ball latch assembly (bending the front of the ball mount) or your connection point on your trailer or equipment.
Variable Speed Throttles
This kind of control allows the end user to start slow, easing tension between the tow dolly/trolly and trailer and work up to a comfortable speed. When stoping or slowing down the user simply alleviates pressure on the throttle for a controlled complete stop. This style of throttle control gives the end user ultimate control over the payload.
Why are other manufactured power dollies so slow?
Winch motors are very slow, and even slower to move trailers, no matter what size, or weight. When moving larger gross weight trailers, some manufactures have opted to stay with a single electric motor. They simply change the size of wheel sprocket in order to create more torque (push/pull power). It's a cheap fix, but it does comes at a cost. The larger gear ratio causes the tow dolly/trolly to move even slower.
Why the price difference between different size dollies?
Sprockets are cheap, normally only costing around $30-$50. So the question is, why do some power tow dolly manufactures charge between $200 - $350 for the larger size power tow dolly if they are only changing one sprocket? That's a question you will have to ask them.
The larger capacity TRAX Power Dollies use 2 motors that offer maximum push/pull power and speed. We never cut corners when it comes to quality and performance.