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NASCAR Sprint Cup Series competitors simply can't risk a substandard shock setup. It literally can be the difference between a 30th-place finish or tasting the champagne in Victory Lane.
Most teams employs at least one shock specialist who is charged with finding the right combination that will allow the car to get as low to the ground as possible without dragging the nose of the Gen-6 model.
Hendrick Motorsport crew chief Alan Gustafson relies on veteran shock specialist Chris Golder to make sure Jeff Gordon's No. 24 Chevrolet SS has precise handling and comfort from Martinsville to Texas and everywhere else on the circuit.
Golder, 33, grew up in Alpharetta, Ga., greasing his passion for restoring cars alongside his dad who owned an automotive repair shop.
Working at the shop through high school and college, Golder says, helped him gain the majority of his mechanical knowledge and experience.
"I have always had an interest in cars," Golder said. "I grew up with three younger sisters and no brothers, so cars were kind of a way for me and my dad to spend time together and to bond. He's the one that got me into racing."
Golder raced go-karts as a youngster and late model trucks at Lanier Speedway in Braselton, Ga., during his college years at Georgia Institute of Technology (Georgia Tech).
After graduating in 2004 with a degree in mechanical engineering, Golder grabbed a gear and drove up to Charlotte, N.C., in search of a full-time racing gig.
With drive and determination, he knocked on the door of what was then the Research & Development shop at Hendrick Motorsports.
Cutting Edge Technology: Most NASCAR Sprint Cup Series teams employ at least one shock specialist -- like Chris Golder -- who is charged with finding the right combination that will allow the race car to get as low to the ground as possible.
Gary DeHart, former championship-winning crew chief for Terry Labonte, answered.
"I talked to him for about an hour," recalled Golder of that day almost 10 years ago. "He told me he was very interested in hiring me and to stay by my phone that maybe during the next week or so he'd call me."
Like a lap around Martinsville, it didn't take that long.
That same day, just two hours later into his drive back to Georgia, Golder got a call from DeHart requesting a formal interview.
"He asked if I could be back on Monday morning for an interview with Rex Stump and Ken Howes," remembered Golder. "I said, 'Sure, I'll be there!' "
The rest they say is history.
Golder began his NASCAR career at Hendrick Motorsports in 2004. Today, as the shock specialist on the No. 24, he works with Gustafson and team engineers Tom Stewart and Tom Gray to determine the best setup packages.
"My main responsibility is the springs and the shocks," Golder explained. "Springs are used to control the height of the race car. At the bigger, faster, intermediate tracks both the front and rear attitude is very important, so we work a lot with springs and spring rubbers, along with the shocks and bump stops."
Daily, Golder spends much of his time configuring and fine-tuning shock-spring combinations for each race track to ensure his four-time NASCAR Sprint Cup Series champion driver has the best possible control over the car.
"I run simulation along with Alan, Tom and Tom to come up with good packages," Golder said. "I work up options around those packages to try and practice to get Jeff’s feedback."
NASCAR does not allow teams to run data during the race weekend, only during test sessions. So, simulation has to be spot on.
"Without data sometimes we don't know exactly what's going on out there on the track," Golder said. "We have to be able to move quickly on our feet since we only get about three hours of practice on a weekend. That time is very crucial and we're prepared to make a change if what we started with doesn't work out."
On race weekends, you can find Golder working inside the No. 24 transporter. His workstation houses a shock dyno that moves at different displacements enabling the team to measure different drive and track profiles.
Golder changes out shims and pistons to make different forces with the shocks. Every track is different and unique and each one demands different valving.
"The front shocks on cars are what we like to call 'aero inhibitors,' " Golder said. "On the front shocks, we have bump stops and we fine tune them to affect the attitude of the race car, to try to keep the nose down. There's a great comprise between running a softer bump stop, which is going to feel better to the driver, verses a stiff stop that's going to keep the nose down and keep the car sealed down to the race track and help improve the aerodynamics."
That delicate balance has become one of the critical points on a race car.
No track is smooth as silk -- without shocks, a race car would bounce all over the place each time it hit a bump or dip. As a race car makes its way around the track, the springs compress and expand when they hit imperfections. The shocks absorb the energy of the spring, keeping the tires on the ground as much as possible. How the car handles depends on which shocks are used and how resistant they are to motion. To control the movement, teams can tweak the piston, shims and oil inside a shock.
As a car hits a bump, a shaft is driven upward in the oil that fills the shock. The piston inside the shock regulates how quickly the shaft moves up (compresses) and down (rebounds). By tweaking the compression and rebound for each specific track, the driver is able to better maneuver the race car.
To keep the oil from foaming and losing its ability to compress and rebound, a shock is pressurized with nitrogen.
NASCAR has strict guidelines regarding how much nitrogen can be in each shock. Rear shocks can have no less than 25 pounds of pressure per square inch (psi) and no more than 75 pounds of pressure psi. Shocks can reach temperatures of up to 200 degrees during a race.
Golder, who maintains approximately 130 shocks during the season, says of those, he re-valves about 200 per year.
At the track, he doesn't let just the front and rear end mechanics get their hands dirty. He installs between 30 to 40 percent of the shocks on the race car himself.
Golder says short tracks and rougher tracks are the toughest on shocks.
"The easiest tracks on shocks are the superspeedways where you're not worrying about mechanical grip," Golder said. "The most technical tracks are the short tracks and the rougher race tracks like Las Vegas and Atlanta. Texas is rough, but it is a big, fast track with a lot of load so we really have to fine-tune aero and mechanical grip balance there."