Technical Information

360° Product Testing has independently determined and documented the performance of Trac-Grabber tire traction innovation via a custom test stand configured with a typical automotive tire. A sample tire was measured for the relative amount of effort/work for improved traction on a variety of materials. Evaluation included simulated “slipping” scenarios.

The Trac-Grabber is an innovation designed to enhance the ability of a slipping tire to extract itself from a poor traction situation. Tested products are summarized by their dominant strap color and overall rubber block dimensions.

Parameter Car / ATV Truck / SUV
Block Length 8” 9”
Block Width 3” 3 1/2”
Block Depth 1” 1 1/2”

Pull Testing

Trac-Grabbers were installed using the D-ring locking with the full length of Velcro. The rubber part of the product was pulled in tension to determine the maximum holding force. The failure mode for both the car and truck-based models was the slipping of the strap against the Velcro. The onset of initial Velcro stress / slippage was noted based on audible sounds.

The ultimate force recorded is the maximum force exerted at which the strapping system could no longer support the load.

The image at right shows a Trac-Grabber installed on a hydraulic ram to test the strength of the retaining straps. In the following table, “Initial Slippage” refers to the applied force at which the Velcro first began “stretching”, while “Ultimate Max Strength” is the applied force at which the strapping system could no longer support the load.

Initial Slippage Truck Strength
Car / ATV 278 lbs 898 lbs
Truck / SUV 278 lbs 1873 lbs

Lost Traction Testing

A custom test jig was created to simulate a tire slipping. The same baseline tire was used to test both car and truck products, which provided the same mass and torque ratios for a direct comparison. A basic “slipping” tire is one that rotates freely without surface traction. The amount of effective tire torque during a slipping situation is nearly zero because the wheel is free to spin.

After the tire was measured in a slipping scenario, the Trac-Grabber product was installed on the test tire. The torque was measured to the point where the tire developed sufficient traction to exit the test bed, or where the tire lost traction while aided by the Trac-Grabber. This traction value is unique to each situation; thus, the important aspect to interpret from the tested data is the numerical trend. As documented below, in each of the tested scenarios, the addition of the Trac-Grabber product added notable torque potential to the fixtured spinning tire.

The side-profile contacting area of the Trac-Grabber is the primary contact surface for creating leverage that provides the additional traction. The applied force is the amount of lateral force exerted on the profile area of the Trac-Grabber in this experimental setup. The applied pressure is the applied force for each square inch of profile area.

The following Constant Mass table demonstrates a constant amount of force needed to “catch” a slipping tire in mud, as well as compares the products using a given slipping tire. The following Constant Mass table demonstrates a constant amount of force needed to “catch” a slipping tire in mud, as well as compares the products using a given slipping tire.

Constant Mass
Slipping Baseline Torque Profile Area Applied Force Applied Pressure
Car / ATV 1.6 ft-lbs 17.3 ft-lbs 9.1 in2 16.1 lbs 1.8 psi
Truck / SUV 1.6 ft-lbs 14.0 ft-lbs 13.5 in2 13.1 lbs 1.0 psi

trac-grabber mud test

trac-grabber sand test

trac-grabber ice test

Hypothetical vehicle and situation:

Assume a 2,400 lbs. vehicle that is uniformly weighted to 600 lbs. per wheel with typical 28" diameter tires. The maximum static torque required to vertically lift the corner of the vehicle is 514 ft-lbs.

Note: The full weight-lifting force is much greater than the normal forward motion driving torque, and does not account for vehicle momentum.

The high (maximum) torque value is based on a vertical lift of the car weight. The Trac-Grabber effectively increases the diameter of the tire. In this example case, the diameter would increase from 28" > 29.5". The larger effective tire size alone reduces the amount of torque needed to lift the vehicle to: 488 ft-lbs. (5% reduction), noting that the height of the stuck obstruction greatly affects the amount of exit torque required.

Example values presented are worst-case maximum static values to vertically lift the quadrant of the vehicle. The Hypothetical Constant Torque compares each product to the performance ability given that a particular vehicle would exert a particular given torque.

Hypothetical Constant Torque
Slipping Baseline Torque Profile Area Applied Force Applied Pressure
Car / ATV 1.6 ft-lbs 488.0 ft-lbs 9.1 in2 454.8 lbs 50.0 psi
Truck / SUV 1.6 ft-lbs 488.0 ft-lbs 13.5 in2 454.8 lbs 33.7 psi

General Comments

  • Straps are very long to provide for attaching to large tires.
  • The Trac-Grabber is intended for installation on open wheels.
  • Results will vary with circumstances, i.e., conditions, operator, tires, and vehicle.

Conclusion

Both the car and truck Trac-Grabber products demonstrated that they notably increased the tested tire’s traction. This is due to an increase in the effective tire height and lift, the paddle effect, and the concentrated pressure on a small surface area.