Understanding Underlift Tow Trucks for Heavy Duty Towing

Understanding Underlift Tow Trucks

Underlift tow trucks, also known as slide tow trucks or chassis tow trucks, are essential vehicles for heavy-duty towing and recovery. With their low-profile design and retractable arms, underlift trucks can slide under disabled vehicles and lift them by their frames or chassis for easy towing. Let's take a closer look at what makes underlift trucks unique and how they get the job done.

What is an Underlift Tow Truck?

An underlift tow truck is a type of carrier tow truck that uses a set of retractable arms (known as underlift arms or crossbars) to lift vehicles off the ground from underneath. The underlift arms slide under the front or rear end of a vehicle and lift upwards, raising the tires off the ground. From this position, the disabled vehicle can be towed away by the truck.

Underlift trucks are categorized as Class V medium-duty tow trucks with a Gross Vehicle Weight Rating (GVWR) of 18,000 to 26,000 lbs. They utilize a boom and cable mechanism to lower and raise the underlift arms. Controls inside the truck allow the operator to carefully position the arms and adjust them to match the chassis or frame of the vehicle being towed.

Benefits of Underlift Tow Trucks

Compared to other tow truck designs, underlift trucks offer some key advantages:

• Low-profile design - The underlift arms slide underneath vehicles with little ground clearance.
• Lift from chassis - Lifting from a vehicle's chassis causes less damage than lifting by the wheels or bumpers.
• Secure towing - Underlift arms cradle the entire base of vehicles for very stable towing at highway speeds.
• Heavy-duty rating - Underlift trucks can tow medium and large vehicles weighing 10,000 lbs or more.
• Flexible operations - Underlift arms allow loading disabled vehicles when loading ramps are unavailable.

These capabilities make underlift trucks ideal for towing and recovering all types of trucks, buses, construction equipment, and more. The slide under design helps underlift trucks safely manage vehicles that are partially off-road or stuck in ditches, snowbanks, and other environments.

Types of Underlift Tow Trucks

There are two main types of underlift tow trucks:

• Rear underlift trucks - Featuring underlift arms that slide under the rear end of vehicles. Rear lifts allow access to vehicles in busy urban areas.
• Front underlift trucks - Equipped with arms that lift vehicles from the front end. Front underlift trucks are useful for towing all-wheel and four-wheel drive vehicles.

In addition, different styles of underlift arm assemblies are available:

• Fixed arms - A fixed crossbar connects the underlift arms, allowing them to be positioned closer together or farther apart.
• Expandable arms - The crossbar can telescope in and out for adjustable width settings.
• Independent arms - Each underlift column operates independently without a crossbar, providing the most flexibility.

Underlift Towing Procedures

Well-trained operators are essential for safe underlift towing. Here are some standard operating procedures:

• Inspect underlift arms and chassis contact areas for damage before towing.
• Carefully slide arms under the chassis, positioning as close to axles as possible.
• Lift vehicle slightly to allow tow truck maneuvering for towing.
• Keep safety chains properly rigged to towed vehicle.
• Check that lifted tires clear obstacles before moving.
• Drive slowly and allow extra stopping distance while towing.
• Avoid sudden stops, starts, and turns to prevent load shifting.
• Lower vehicle using gradual arm descent for a gentle set down.
• Remove underlift arms carefully to avoid damaging vehicles and arms.

Proper underlift operation minimizes the potential for accidents and equipment damage. Operators should be trained on manufacturer's instructions for their specific underlift models.

Key Underlift Truck Manufacturers

Major underlift truck manufacturers include:

• Miller Industries - Maker of Vulcan, Century, Challenger, Holmes and Champion brand underlifts.
• Jerr-Dan - Specializes in heavy-duty underlift trucks for towing and recovery applications.
• Dynamic Towing Equipment - Leading manufacturer of low-profile, lightweight underlift systems.
• Towmaster - Maker of underlifts for light, medium and heavy-duty towing jobs.
• United Recovery Industries - Affordable underlift trucks for basic towing needs.

With their unique capabilities, underlift trucks will continue to serve an important role for vehicle towing and transport businesses in the future. Understanding underlift design and proper operation techniques helps ensure safe and successful towing.

The Bottom Line

Underlift tow trucks use retractable, low-profile arms to lift vehicles by their chassis for stable towing. Sliding under disabled vehicles causes less damage than other towing methods. When operated by trained professionals, underlift trucks provide flexible, heavy-duty towing capacity ideal for trucks, buses, and construction equipment.

FAQs

What is the lifting capacity of underlift tow trucks?

Underlift trucks are rated as Class V medium-duty trucks, meaning they have a gross vehicle weight rating (GVWR) between 18,000-26,000 lbs. Specific lifting capacities depend on the underlift model, but most can safely lift and tow vehicles weighing 10,000 lbs or more.

Can an underlift tow truck pick up a vehicle with flat tires?

Yes, underlift trucks are designed to slide under and lift vehicles by their chassis, so they do not require inflated tires in order to tow. The underlift arms cradle the base of the vehicle for stability.

What types of vehicles can be towed with an underlift truck?

Underlift trucks are ideal for towing medium and heavy-duty vehicles like trucks, buses, vans, construction equipment, farming equipment, and more. Their low-clearance design works well for partially off-road vehicles.

Are underlift tow trucks safe to operate at highway speeds?

Yes, underlift arms securely cradle and lift the entire base of vehicles, allowing for safe towing at normal highway speeds. Proper load balancing and extra stopping distance should be maintained.

How can improper use of an underlift truck cause damage?

Improper arm placement under the chassis, sudden lifting or dropping, and driving too fast while towing can cause vehicle damage. Operators should follow manufacturer procedures to avoid accidents and equipment damage.