Based on sightings on the highways and at motorhome rallies and conventions, four wheels down appears to be the preferred method of towing.
More auto manufacturers seem to be noticing this preference and are providing specific flat-towing information in their owners manuals and product literature.
Since 1999, Family Motor Coaching magazine has published an annual towing guide that lists the current model-year vehicles that auto manufacturers have approved for flat towing.
It appears that manufacturers are approving more vehicles for towing four wheels down without significant speed or distance limitations and without major mechanical modification.
What makes a vehicle towable four wheels down? Two factors: One is mechanical and the other is the manufacturer's policy. Some vehicles can be towed from a mechanical perspective but have not been approved or endorsed for towing by their manufacturer. Often, this is the combined decision of several groups, such as sales, marketing, engineering, service and legal.
Some vehicles not endorsed by their manufacturers for towing can be towed provided certain mechanical modifications are made to the towed vehicle. For instance, installing a drive-shaft disconnect, an axle lock, or a lube pump to lubricate the towed vehicle's transmission.
Lighter-weight cars, SUVs and pickup trucks are popular vehicles to tow four wheels down. But do not purchase a vehicle just because you've seen others towing it. The owners may have made modifications to make it suitable for flat towing.
Before purchasing a vehicle for towing four wheels down, obtain a copy of the vehicle owners manual and determine the manufacturer's official position relative to this type of towing. This information usually is contained under a bold heading called "Recreational Towing," "Motorhome Towing" or "Dinghy Towing." Read the manual yourself; do not rely on hearsay. In the manual, do not confuse recreational towing with emergency towing; some vehicles can be pulled four wheels down in emergencies only.
Talk with the dealership service manager and ask whether any service bulletins relating to towing a particular model have been issued. Vehicle manufacturers use service bulletins to communicate information to dealers regarding technical issues, including towing of their products.
The next step — again, to be taken before the actual purchase -- is to check the towability of the vehicle and determine whether a base plate is available for it. Towability is a function of how well the towed vehicle will track behind the motorhome.
Base plate availability is a concern, because most modern cars have impact bumpers and cannot be towed safely from their bumpers. An alternate method of attaching the tow bar to the car is required. The base plate provides a factory-engineered method of doing so and offers the assurance that the car can be successfully towed. Base plates also can be custom-built at professional hitch shops. Contact towing equipment manufacturers and suppliers to check whether a base plate is available.
To ensure a safe tow bar installation, the coupler of the tow bar should be as level as possible when the motorhome and the car are on flat ground. To accomplish this and still deal with the practical problems of proper attachment to the vehicle's chassis, some tow bars incorporate a "step" in the design of their products. The "attachment tabs" end of the tow bar is 5 or 6 inches lower than the coupler.
Always follow the towing procedures and guidelines exactly as outlined in the owners manuals.