In the past, when you’ve been watching a NASCAR race, have you noticed when the announcers are talking about a pit crew preparing to perform a wedge adjustment on a car? You might have just taken that for granted as something that often happens in NASCAR racing, but do you know what they are actually doing? In this article, we’re going to try and explain in better detail what a wedge adjustment is, and why it matters.
A wedge adjustment is an adjust to tighten of loosen suspecian, usually over the rear wheels. Tightening the wedge adds weight to the NASCAR Race Car and loosening reduces tension. These Wedge Adjustments help prevent under and oversteer during the race and help control the handling of the car.
In simple terms, a wedge adjustment refers to the time when a pit crew alters the level of tension on rear suspension springs. If you’re a motorsports fan and have seen how fast they work in these pit crews, an adjustment to the suspension of any kind might be the furthest thing from your mind when you picture the specific tasks they carry out, but it does happen.
How can a pit crew, no matter how talented or experienced, carry out something like a suspension adjustment in a typical pit stop? Wouldn’t they have to get into the bowels of the car somehow? At the very least, wouldn’t they have to raise the car or get under it somehow? In fact, none of this is necessary, and the adjustment is quite simple thanks to the ingenious construction of the NASCAR stock car.
When looking at a NASCAR vehicle, have you ever noticed at the back that it has small holes in the rear window? These holes are the entry point through which pit crews can access the necessary tubes that connect directly with the car’s suspension system. At these holes are two jack bolts, onto which a pit crew tire changer can attach a special extended ratchet. Turning the ratchet, the tire changer either adds or subtracts wedge from the car.
Adding wedge means compressing the spring adds more of the car’s weight to the corner where that spring resides. Subtracting wedge is when the spring is loosened, reducing the overall tension.
Suspension springs are a critically important component in the construction of a NASCAR vehicle. Their most vital function is helping to ensure that tires never become separated from the track, and traction is continuously maintained.
Springs absorb the energy that a car would get hit with when encountering any kind of bump or imperfection on the track, and even push back to ensure the tire remains on the ground.
It sounds simple, but things get harder and more complicated with maintaining traction when you’re taking corners at high speeds. With regular cars on the road, this can be regulated with speed limits and good driving habits.
However, in a NASCAR race there is a requirement for drivers to tackle corners at great speeds in order to remain competitive. So, wedge adjustments are important for adapting the suspension to the required conditions that will help maintain traction.
Besides helping in maintaining traction in general, there is a more important reason for wedge adjustments, and that’s in maintaining proper cross-weight — or wedge — when handling a NASCAR vehicle.
Wedge adjustments are only carried out on the rear wheels, and quite often just on one rear wheel. Cross-weight refers to the related weight that exists between the right-front and left-rear wheels on a NASCAR vehicle. It is typically measured as a percentage of the car’s overall weight.
Having more than 50 percent of the vehicle’s weight on the left-rear wheel and right-front wheel is understood as the car having more wedge. Increasing the wedge in this way on a left turn ensures that you don’t oversteer when taking the turn at higher speeds. If the team feels, however, that the driver is vulnerable to understeering, then they will subtract wedge to create better driving conditions.
In a NASCAR race, just as with all major motorsports like Formula 1 and IndyCar, every single second on the track counts. There’s virtually no room for error, and conditions are shifting with every lap that cars take. As we have discussed in other blog pieces, the vast majority of NASCAR tracks are paved with asphalt, the binding in which quickly comes undone during the extreme heat, wear and tear of a race.
Changing grip on the track, and the effects of heat and cold mean that cars have to be “updated” as the race progresses, and one of those key changes is the wedge adjustment. It creates a new suspension configuration that suits the latest conditions of the track.
It is for this reason that it is so critically important not just that wedge adjustments can and do happen in general, but that they can be done quickly and accurately during the race to allow a driver to stay in the race.
We know that pit crews use a special extended ratchet to turn the bolts and adjust the springs, but to what degree do they adjust them? Are multiple turns of the ratchet usually necessary? Adjustments to the springs are measured in “turns” which refers to a full-circle rotation of the ratchet. Another term used for measuring is “rounds.”
Most often, the car only needs a half turn either way to either add or subtract wedge to the vehicle. More than that would mean there are some more extreme changes or conditions that the team is facing on race day.
Furthermore, the vast majority of adjustments are only made to the rear springs, which means simply attaching the ratchet to the bolts and turning. In the unlikely event that a front spring does need adjusting, it would entail opening the hood, which would mean a slower pit stop time.
Anything that can give an edge to a NASCAR Race car is welcome, and the adjust of car handling is right up there in importance.
The ability to change the cars handling, quicky, during the course of the race is a huge benefit, especially as tracks change during the course of the race.