TOKYO, December 9, 2004 - Kobe Steel, Ltd. has developed a high-speed tire testing machine, the 100D26-LH, that accurately measures tire uniformity.  At 200 km per hour (2,300 revolutions per minute), the new uniformity machine is one of the world's fastest.

Automobiles are being designed for higher performance, superior handling and driving stability.  However, tire unbalance can affect handling and ride quality.  Tires are made by laminating rubber, chemical fibers, steel cords and other materials.  When a car is in motion, unbalance in the tires create vibrations that are transmitted to the auto body.  Auto makers and tire manufacturers have been conducting research to improve tire balance.

In a tire uniformity machine, a test tire on a fixed spindle is spun by a rotating drum.  Measurements are taken on the radial force, lateral force and tractive force variations and unbalance in the tire.  Measurements are generally conducted at a low speed of about 8 km per hour (60 revolutions per minute) under Japan's JIS standard, making it difficult to accurately predict unbalance at high speeds.  

As a result, automobile manufacturers have been running their own tests at higher speeds.  However, Kobe Steel's current tire uniformity machine, with a top speed of 120 km per hour, does not accurately measure data at higher speeds due to vibrations in both the test equipment and tire.  Demand has been growing for a high-speed tire testing machine that precisely measures and provides analytical data on tire uniformity.

The 100D26-LH high-speed tire uniformity machine, developed for laboratory use, has a low center of gravity owing to its horizontal operation.  Additionally, in a design that utilizes stronger parts and materials, vibrations created by the machine and tire are eliminated.  The natural frequency of the new machine is 350 Hz, double that of conventional machines.  The new machine enables more accurate measurements of tire unbalance at high speeds to be taken, in comparison to conventional tire uniformity machines.

Kobe Steel has also developed the 100D26-PH tire uniformity machine for use by tire makers on their production lines.  Kobe Steel has begun marketing these two machines in Japan, North America, Europe and Asia.