ASFT Continuous Friction Measuring Equipment

Sweden-based ASFT develops and supplies equipment, control technologies and services related to the measuring of friction on roads, providing a tool for disaster prevention. ASFT is committed to both roads and airports. The company is the world’s largest supplier totally devoted to friction testing.

ASFT offers friction testing systems mounted onboard cars (rear axle systems) and trailer mounted systems. Other products and services include computerized support systems, spare parts and service, training and upgrading, as well as consultation services.

Continuous friction measuring equipment

ASFT continuous friction measuring equipment (CFME) is referred to as the skiddometer principle or fixed slip device. It operates with a fixed longitudinal slip of about 13% on the test wheel. The advantage of a slip measurement is that it can provide a continuous record of the friction.

Friction tester vehicle

A road should not constitute an unacceptable risk for accidents like skidding, falling over, collisions etc. There is a need to establish if a road has a surface that allows safe traffic. Based on this need we developed the ASFT Volkswagen Sharan Road CFME. The ASFT VW Sharan CFME is a friction tester vehicle operating with a fixed longitudinal slip of about 13% on the test wheel.

The ASFT VW Sharan is covered in the ISO IS 8349-standard for road friction measurement developed by ISO subcommittee TC22/SC9 working group WG3. The typical measuring tire is either the smooth ASTM 1551, or the Trelleborg T49. It can also be equipped with a self-watering system. The standard tank capacity is between 500l and 1,200l.

Road surface testing

In 1993 the PIARC committee for road surface characteristics carried out the ‘International PIARC Experiment to Compare and Harmonize Texture and Skid-resistance Measurements’. The final report was published in 1995. One conclusion drawn was that the ASFT CFME testing system correlates to British pendulum and scrim at three different target speeds: 30km/h, 60km/h and 90km/h.

Rear-axle surface friction testers

The ASFT MK IV rear-axle is a new generation of surface friction testers based on the highly successful mark II system. The rear-axle has a third smaller wheel on a transmission arm attached to it via three chains. This is the measuring wheel, and it provides friction readings that closely correlate with true friction values from moving vehicles.

New-generation CFME computer system

Combining all our knowledge about friction testing and adding new technology to make the administration of measurement results easier, faster and more reliable, the main goals of the new-generation CFME computer system are:

• Standard reliable proven techniques
• Traceability of measurement results
• Authentication of operators
• Global mapping service
• Ability to save geographical coordinates of results
• Ability to remotely monitor use of the equipment and real-time viewing of measuring
• Embedded Microsoft® Windows® operative system with touch screen computer

ASFT has its own production plant, and R&D. This has resulted in products of unmatched quality and life expectancy with the average ASFT friction tester being used for 20 years. ASFT friction testers have also been found to have among the best repeatability and correlation in the industry. More than 300 ASFT friction testers are in operation around the world.