What Are Jack Stands and Why Do You Need Them?

If you have ever peered into a professional repair shop or watched a neighbor working on their car, you have likely seen four-legged metal towers tucked under the vehicle frame. These are jack stands. While they might look simple, they are among the most important automotive tools in any garage.

Whether you are performing a basic oil change or swapping out a set of brake pads, understanding what are jack stands and why do you need them is the first step in moving from a casual observer to a capable DIY mechanic. In this guide, we will break down what these tools are, why they are a non-negotiable part of your garage equipment, and how to use them safely.

What Is a Jack Stand?

A jack stand is a static, mechanical support device designed to hold the weight of a vehicle once it has been lifted into the air.

It is important to distinguish them from floor jacks. While a floor jack is a piece of automotive equipment used to raise a car, a jack stand is designed to hold it there. They typically consist of a wide, stable base, a vertical support column, and a saddle—the notched metal top where the vehicle actually rests.

Most jack stands are constructed from heavy-duty steel or cast iron. Unlike the floor jack used to get the car off the ground, they do not have wheels, motors, or hydraulic fluids. Instead, they rely on a simple, robust locking mechanism to keep the support column at a specific height.

What Does a Jack Stand Do?

The primary job of a jack stand is to provide a fail-safe support system. When you use a floor jack to lift a car, you are relying on hydraulic pressure to keep thousands of pounds of metal suspended. If a rubber seal inside that jack fails or a valve leaks, the car will drop instantly and without warning.

Jack stands take the hydraulic variable out of the equation. Once the vehicle is lowered onto the stands, the weight is supported by solid metal-on-metal contact. This creates a stable platform that allows you to work under or around the vehicle without the risk of the car falling. This makes them a fundamental part of any DIY automotive tools collection.

How Are Jack Stands Used?

Using jack stands is a straightforward process, but it requires precision and a focus on safety.

1. Lift the Vehicle: First, you use a floor jack to lift one corner or one side of the vehicle.
2. Position the Stand: Once the car is at the desired height, you slide the jack stand underneath a designated lifting point.
3. Locate the Support Points: Automotive manufacturers design specific areas of the vehicle frame to handle concentrated weight. These are often called pinch welds on unibody cars (like a Toyota Camry) or frame rails on trucks and older SUVs (like a Chevrolet Silverado).
4. Lower and Set: You align the saddle of the jack stand with this point and then slowly lower the floor jack until the vehicle’s weight is fully transferred to the stand.
5. The Shake Test: Once the car is on the stands, give the bumper a firm shove. If the car wobbles, the stands are not positioned correctly. It is much better for a car to fall off a stand while you are standing next to it than while you are underneath it.

When Would You Need Jack Stands?

You need jack stands any time you plan to put any part of your body under a vehicle or when you need to remove a wheel for an extended period. Here are a few real-world examples:

• Brake Repairs: If you are replacing rotors or pads on a Ford Explorer, you need the wheel off. A jack stand ensures the car stays up while you are reaching into the wheel well.
• Oil Changes: On many modern cars, the oil drain plug is located far enough back that you must crawl under the engine. You should never do this with only a hydraulic jack holding the car.
• Suspension Work: Replacing shocks or struts requires the vehicle to be stable for a long time as you use heavy tools to loosen stubborn, rusted bolts.
• Long-term Storage: If a project car is going to sit without wheels for weeks, jack stands prevent a floor jack from slowly losing pressure and dropping the car onto the rotors or the garage floor.

Types of Jack Stands

When looking for car tools, you will generally find two main types of jack stands:

Ratcheting Jack Stands

These are the most common variety found in home garages. They feature a notched center bar that clicks into place as you pull it up. A handle on the side locks the teeth of the bar. They are very fast to adjust, but you must always inspect them to ensure the locking pawl is fully engaged in the teeth.

Pin-Style Jack Stands

These use a thick steel pin that passes through pre-drilled holes in the support column. Many mechanics prefer these because they offer a visible, physical lock that cannot slip like a worn ratchet tooth might. They take slightly longer to set up but offer excellent peace of mind.

What Should You Look for When Choosing Jack Stands?

When shopping for garage tools, do not simply buy the cheapest jack stands available. Consider these critical factors:

• Weight Capacity: This is usually measured in tons. A 2-ton set might be fine for a small sedan, but a heavy electric vehicle or a full-size truck will require 3-ton or 6-ton stands. Always check your vehicle’s weight in the owner’s manual. Note that jack stands are usually rated per pair, meaning a 3-ton set is rated to hold 6,000 pounds when used together.
• Height Range: If you are working on a lifted Jeep, you will need high-lift stands. If you have a low-profile sports car, you need stands that can fit under the frame even when the car is relatively low to the ground.
• Base Width: A wider base provides more stability. This prevents the stand from tipping over if the vehicle is bumped or if the ground is slightly uneven.
• Construction: Look for clean welds and heavy-gauge steel. Avoid any equipment that looks flimsy or has poorly cast metal parts.

DIY vs. Professional Use

For the DIY automotive enthusiast, jack stands are a foundational investment. Most home mechanics do not have access to a professional automotive equipment setup, like a two-post hydraulic lift that raises the entire car above their head. Jack stands are the affordable equivalent, providing a professional level of safety in a driveway or home garage.

While professional mechanics use lifts for most jobs, they still keep jack stands in their mechanic tools inventory for holding heavy components like axles or transmissions, or for supporting a vehicle when a lift is already occupied.

Common Mistakes When Using Jack Stands

One frequent mistake is using jack stands on soft ground, such as asphalt on a hot summer day or dirt. The small feet of the stand can sink into the soft surface, causing the car to tilt and fall. Always use them on a flat, level concrete surface.

Another mistake is placing the stand in the wrong spot. Placing a stand under a thin floor pan or a plastic side skirt will result in crushed bodywork and an unstable car. Always refer to your owner's manual to find the reinforced factory jack points.

Safety Considerations

Safety is the entire reason jack stands exist. Never trust your life to a hydraulic seal. Even if you are just reaching under the car for a second to grab a dropped bolt, the stands should be in place.

Additionally, it is a good habit to practice triple redundancy. Leave the floor jack in place (tightened but not holding the full weight) as a secondary backup. You can also place the removed wheels under the frame of the car for a third layer of protection.

Frequently Asked Questions

Can I use wooden blocks instead of jack stands? No. Wood can split, rot, or compress unexpectedly under the immense pressure of a vehicle's weight. Jack stands are engineered and tested specifically for these loads; scrap lumber is not.

Do I need two jack stands or four? If you are only lifting the front of the car, a pair (two) is sufficient. If you need the entire vehicle off the ground, you will need two pairs (four). Never support a car with an odd number of stands, as it creates a pivot point that can lead to instability.

How do I know if my jack stands are safe to use? Before every use, check for cracks in the metal, deep rust, or bent locking pins. If the ratcheting teeth look rounded or worn down, replace the stands immediately.

Conclusion

Understanding what are jack stands and why do you need them is vital for anyone interested in maintaining their own vehicle. They may be the least exciting tool in a mechanic's arsenal, but they are undoubtedly the most vital for personal safety. They turn a precarious situation—suspending thousands of pounds of steel—into a controlled and stable environment.

By choosing the right capacity, using proper lifting points, and never skipping the shake test, you can perform your own vehicle repairs with the confidence that you are protected from equipment failure. For any beginner looking to build a collection of vehicle repair tools, a high-quality set of jack stands should be at the very top of the list.