Long races like the 600-mile Charlotte race and any race with extreme track conditions will require drivers to pull into the pitstop and do rapid maintenance. As a car runs full throttle through the high-speed race, many components are going to start to reach their limits and will need to be fixed for car performance and driver safety.
That is why a crew chief will call for a pit stop several times during the biggest race.
Key Points:
- Wedge is an important adjustment made by pit crews to NASCAR cars’ suspensions to ensure optimal weight distribution and control while racing.
- A driver may signal a need for a wedge adjustment when the car feels off-balance or when the back tires don’t grip as tightly as desired.
- Making wedge adjustments can be done via a ratchet, with each one affecting all four of the car’s wheels inversely with a cross-weight effect.
The pit crew tune-up includes fuel refilling, tire changes, and a wedge adjustment, all of which impact the driver’s ability to finish the race. Without out the adjustments made to the wedge during the later laps of a race, a driver would have more and more difficulty controlling their cars to make seconds-shaving turns or avoid collisions from abrupt obstructions. As important as this sounds, a casual NASCAR fan is bound to wonder what the heck a wedge is.
What Does the Term Wedge Mean?
Change the tension on a spring in the rear suspension, wedges are the force in the spring, and by making the wedge looser, the car becomes bouncier and able to handle rougher terrain with fewer bumps. Alternatively, tightening the wedge will keep the car tight to the road and can help reduce drag on flat roads that don’t have rough conditions warranting extra loose suspension.
Springs with a tight wedge will push down against up force when a car is taking a tight turn and allow for proper weight distribution preventing the tire from losing contact with the road.
What Is a Wedge Adjustment?
These are minuscule adjustments that allow each suspension to grab the road differently, allowing for optimal handling for a driver to win a race. These adjustments are made before a race and during pitstops as the driver gets a better feel for the track. If an adjustment is needed, the amount to move up or down needs to be communicated quickly and accurately.
Wedge adjustments are referred to as adding a wedge or subtracting a wedge to increase or reduce tension on the springs in the race car’s suspension. This is important because the diagonal relationship between the back-wheel suspension that is adjusted and the corresponding front-wheel affected is known as cross weight. If the distribution of weight by the wedge adjustment on the rear suspension adds more than 50% of the heft, then that side is said to have more wedge.
How Do Pitcrews Perform Wedge Adjustments?
While an expert race team may keep the adjustments accurate for a memorable track, most courses need to be driven on before the team will know what the suspension needs. Depending on track conditions, weather conditions, and the type of race, the crew chief and driver will know what needs to be adjusted.
The driver will tell the crew at the pit to adjust the wedge a turn or a half-round. These are the terms used for wedge adjustments that literally state what needs to be done. The pit crew will use an extended ratchet to reach through the rear window and adjust the bolts that hold the support post that houses the suspension spring
To save time, calculations are made to figure out what single adjustment will provide the suspension the car needs. Once determined, the crew will adjust one back wheel’s suspension, and all 3 other wheels are affected inversely. This cross-weight effect makes performing wedge adjustments lightning fast.
When Is a Wedge Adjustment Needed?
It is hard to determine exactly when a wedge adjustment will be needed, but it is safe to safe that the driver will know what needs to be done and when. Usually, the driver will signal the crew chief anytime the car doesn’t feel right or if the right side had lifted up on the last sharp left turn. It is also common for a driver to call for a wedge adjustment if the back tires don’t grip tightly enough and the car either oversteers or understeers.
NASCAR Suspension Systems
Streetcar suspensions are complicated mechanisms, and the rear springs and assembly in a NASCAR vehicle are even more tightly wound. These complex suspension systems are crucial for NASCAR vehicles to survive the rigors of the most intense race conditions. Below is a breakdown of the main components of the suspension system, where they are found, and what they do.
| Component | Location | Function |
| Shock Absorbers and Springs | Between Tires and chassis | Absorb impact, provide for a smooth ride and create a counter force to keep tire grip tight throughout the entire race |
| Bushings | Anywhere two suspension components meet | Reduce friction and allow for movement without snapping rigid parts |
| Chassis | Bottom support of the car | The skeletal system that holds the entire vehicle together |
| Sway Bars | Between the body and chassis | Prevents the car from pulling too hard to the right during a turn by pushing down against the centrifugal force |
| Steering Assembly | All the pieces that connect the steering wheel to the tires | This is what allows the driver to control the car |
| Tires | Under the wheel wells of the chassis | The rubber that meets the road and propels the racer to the finish line |
Shock Absorbers and Springs
The shocks and springs are what allow a racer to hit the track so hard and so fast without the vibrations and jolting of the track breaking them apart. On road race courses, some of the toughest races for cars suspension systems, these components are crucial for a successful race
Bushings
Hold together parts of the suspension that need to be tight and stiff but still able to move with the motion of the vehicle. When the suspension takes a hard knock that would normally cause structural damage to the sway bar or other parts, the bushing takes the strain and wears down a bit. The race team will carefully inspect these before each race, as a broken bushing makes driving feel like you are drunk.
Chassis
Consists of a main frame and two subframes, the front frame and the rear frame. All components of the car’s suspension system connect to one of the frames of the chassis. The sections of the frame allow for precise customization and reduce negative high-speed aspects like vibrations and rigid movement. The chassis is the strongest part of a car and keep the driver protected from underneath in the cockpit during races.
Sway Bars
Commonly called anti-roll bars, these assemblies help to keep cars from flipping to the right when a driver speeds into a left turn. Without these bars, a car’s tires may lose traction with the road, and on some types of tracks, it could lead to a crash. Controlling the strong pull is one of the reasons restrictor-plate races were implemented.
Steering Assembly
All parts of the car, from the steering wheel to the tires, are part of the steering assembly. If anything were to happen to this component on race day, the driver would be SOL. The main parts of the assembly are affixed to the chassis and wheels with knuckles and tie-rods. Adjustments to this system are not easy for a pit crew to do during an official race.
Tires
Whether it is a traditional oval track or one of the road course races, the tires take most of the heat. On larger tracks, tires will need to be changed often, or the driver will be limited in their speed and control. The rest of the suspension system helps the tires and wheels stay tight to the ground during uneven weight distribution while also having the flexibility to make quick turns and avoid crashes and obstacles.
