The Differences Between Car Haulers & Tow Dollies

The phrase “car hauler” is properly used to identify long-haul truckers who make a living moving automobiles from one place to another, and also to their 18-wheeler rigs. The term is often misapplied to car carriers -- trailers designed to accommodate one car with all four wheels off the ground. Both car carriers and tow dollies are offered for rent by national van rental companies like U-Haul (uhaul.com), Penske (pensketruckrental.com) and Budget (budgettruck.com).

Car Carriers

  • Car carriers are flat-tow trailers designed or adapted to allow a vehicle to be transported with all four wheels off the ground. They typically have two axles near the center, which translates into four wheels, all of which are usually fitted with electric brakes. U-Haul rates their 2,290-pound empty-weight car carrier as capable of carrying a 5,290-pound vehicle. The towed vehicle must have an outside-to-outside tire width maximum of 79.25 inches, and a body width maximum of 133 inches.

Tow Dollies

  • Tow dollies are single-axle trailers fitted with a spectacle-shaped support frame that accommodates both wheels of only one of the axles of a towed vehicle. The other axle is on the ground, and thus subject to all the wear-and-tear issues -- including blown tires -- of regular driving. Tow dollies seldom have electric brakes. U-Haul rates its 750-pound empty-weight tow dolly as capable of carrying a 3,450-pound front-wheel drive vehicle and a 3,900-pound rear-wheel drive vehicle. The towed vehicle must have an outside-to-outside tire width maximum of 72 inches, and a body width maximum of 75 inches.

Disadvantages of Car Carriers

  • Car carriers are much heavier than dollies. While this imparts far greater stability to the tow, it also translates into a greater fuel-use penalty and usually a higher rental price. A mid-range or larger vehicle is needed to safely pull a laden car carrier. For local, low-speed tows, a dolly may represent a savings.

Disadvantage of Tow Dollies

  • Tow dollies lift only one axle off the ground. Because the lifted axle is almost invariably the front -- so the steering can be incapacitated -- the usual practice is to dolly-tow with the rear axle on the ground. This will very quickly destroy the gearbox of a rear-wheel-drive car with an automatic transmission. Four-wheel-drive vehicles such as Range Rovers that have a high/disengaged/low ratio gearbox can be shifted into the disengaged position and towed safely. Otherwise, the drive shaft that connects the rear axle to the transmission must be disconnected. Consult the vehicle owner’s manual specific to your vehicle to learn how to do this. Dollies are far less stable than car carriers. At relatively low speeds they can cause the towed vehicle to “wag," which at best is a disconcerting experience and at worst can cause separation from the tow vehicle and trailer rollover. The angle of approach when loading a car onto a tow dolly is more extreme than that of a car carrier. Low-profile cars, or cars with spoilers and side skirts, may not load without damage.