A Lighter, More Aerodynamic Wheel

Making road wheels lighter helps improve a vehicle's fuel economy. But making them more aerodynamic can produce a greater boost, according to Lacks Wheel Trim Systems LLC.

The Grand Rapids, Mich.-based wheelmaker says its new eVOLVE system does both. Lacks debuted the architecture last week at the Los Angeles auto show.

In independent tests, Lacks' multi-material architecture reduced per-wheel weight by 4.5 lbs and boosted the fuel economy of a Ford Focus SE with 17-inch wheels by 1.1 mpg on the Environmental Protection Agency's highway fuel economy cycle.

A car's wheels turn at about 1,000 rpm at highway speeds, notes James Ardern, director of business development. Conventional styled wheels act as propellers, pumping air through their spokes and creating unwanted drag.

The eVOLVE design permanently bonds an aerodynamic high-impact polymer cladding to a lightweight aluminum "backbone" wheel structure. Ardern says the combination produces significantly greater benefit than using the unclad backbone wheel alone.

Layering a backbone wheel with decorative cladding isn't a new idea. Lacks began using the technique in 1997 and has since supplied some 24 million wheels under its Chromtec brand to major carmakers worldwide.

Ardern says the eVOLVE concept represents the company's first effort to focus specifically on the aerodynamic aspects of the cladding. He points out that carmakers overlook the aerodynamic contribution of wheel design if they conduct wind tunnel tests with the vehicle's wheels at rest.