New lightweight wheels
Contribution to fuel efficiency by roughly 15% wheel weight reduction

Topy has developed ISO-compliant wheels that are about 15% lighter compared to the corresponding conventional wheels by combining a corrugated rim that uses Topy’s inherent weight reduction technology with an ECOD-processed disc. The corrugated rims are produced from rim sections with uneven thickness in a corrugated shape on their tire-mounting side, allowing the sections to achieve an optimal thickness distribution when roll-formed. The rim material is produced by the Steel Division and shipped to the Wheel Division to undergo process forming into rims, capitalizing on the advantages of our integrated production system that enables us to combine our unique hot-rolling steelmaking technologies with superior analysis and design wheelmaking technologies. The ECOD discs are formed through cold spinning (rocking die forming) of a tube made of steel plate, enabling thinner and lighter discs without compromising the required strength.

Hot-rolled high-strength rim material
Wheels assuring vehicle weight reduction and collision safety

Automotive manufacturers are increasing their use of high-strength steel that enables chassis weight reduction while maintaining equal strength to conventional steel as this allows the achievement of both reductions in fuel consumption due to lighter body weight and improvement in collision safety. Topy has been working on the use of highstrength hot-rolled special sections for truck and bus wheel applications. A challenging issue for raw material was how uniform strength could be attained. We have succeeded in commercial production thanks to our inherent hot-rolling technologies for controlling material thickness and temperature.

Non-chrome pre-treatment of aluminum wheel painting
An industry first for chromium-free processing

Surface treatment of aluminum alloy wheels has long been developed with a focus on long-term corrosion resistance and anti-discoloring, and treatment with chromium was thought to be vital for anti-corrosion properties. However, in view of European environmental regulations, Japanese automobile manufacturers have turned their attention to surface treatments that avoid the use of heavy metals such as chromium. Topy has spent substantial time on the study and technological development of alternative materials to replace chromium, and has succeeded in a chromium-free process for the first time in the industry.

Ultra-large diameter wheel SGOR® for mining dump trucks
The world’s largest wheel contributing to efficient mining operations and hauling

SGOR® (Super Giant Off-the-road Rim) wheels are ultra-large diameter wheels that Topy has developed for dump trucks used at large-scale mining sites across the world. Currently, the largest wheels available have dimensions of 63 inches (about 1.6 m) in inner diameter, 44 inches (about 1.1 m) in width and weigh as much as 2.83 tons each, being about five times the diameter of ordinary passenger car wheels. SGOR® wheels can meet the demanding requirements of mining applications in terms of functionality and hauling capacity, contributing to the reduction of environmental burden.