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Jeff Horton appears to be having way too much fun watching wound Zylon cords snap under extreme force at the Indy Racing League testing lab. But it’s all part of the job for the league’s director of engineering.

Horton and IndyCar Series technical manager Kevin Blanch were testing the breaking point of SWEMS (Suspension Wheel/Wing Energy Management System) – which are attached to each wheel and the rear wing of IndyCar Series and Indy Pro Series cars to minimize the possibility of assemblies becoming detached during high-speed crashes.

Off-season testing, in an effort to provide teams with the best and most cost-effective equipment, is standard procedure. The front and rear suspension SWEMS (three on each wheel assembly, according to the Indy Racing League 2006 rulebook) must be attached to the chassis. One or two rear wing restraints must be attached to the transmission. Each restraint must have a break load of 100 kilonewtons (kN), which equals 22,480 pound-force (50 kN each if using two rear wing restraints).

The Indy Racing League introduced SWEMS in 1999.

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“We do have several on each wheel and two on each wing, so a single failure does not mean it is detrimental to the retention system,” Horton said.

“Part of the motivation with the SWEMS testing was to see how they degrade over time – by heat and just the wear and tear because of the mechanics. We were validating what our spec is in our rulebook with new components, and looking at the cost aspects. We’ve had some companies approach us with the same materials but different build methods and we needed to validate their parts.

“We always look to get teams more cost-effective components, and it looks like we’re headed down that road. Same quality, same spec, just a less expensive version.”

Visual inspection of the restraints is a part of the initial safety inspection on event weekends. If any of the four corners sustain an impact, the rulebook mandates changing the SWEMS on the affected corner.

“Typically, they are changed when they’ve had damage – accident or normal wear and tear,” Horton said. “That’s one of the things we’re trying to come up with is a normal life cycle. The teams are very good; they understand the importance of it.”

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