When working on a vehicle, using jack stands is an essential safety step. Jack stands support the vehicle after jacking it up, preventing it from falling unexpectedly and injuring someone underneath it. But how many jack stands are actually needed to properly support a vehicle? Is two enough, or do you need more? In this article, we’ll explore the pros and cons of using two jack stands and look at factors to consider when determining if two stands are sufficient.
The Purpose of Jack Stands
Before looking at how many jack stands are ideal, it’s important to understand what they do. Jack stands support a raised vehicle, providing a stable base and preventing the jacked-up car or truck from slipping, falling, or rolling unexpectedly. Having a vehicle supported only by a jack is very dangerous, as jacks can fail or lose height, causing the vehicle to come crashing down.
Jack stands catch the vehicle’s weight if the jack gives way. They keep the car or truck securely lifted so that you can work safely underneath it. Jack stands come with ratcheting mechanisms to lock them at a desired height. The weight of the vehicle on top keeps them in place. Jack stands are always used in pairs or sets of four, with one placed under each jacking point on the vehicle.
The Argument for Two Jack Stands
For many automotive jobs, using two jack stands seems sufficient. With one under each end of the vehicle, two stands catch the front and rear weight. The thinking is that this covers both “corners” of the car or truck. The vehicle cannot tip from side to side or front to back if the two ends are supported.
Placing two jack stands under opposite sides also balances the weight evenly. The vehicle won’t tilt or sway on the stands. Some other perceived benefits of using only two jack stands include:
- Less equipment needed – Only two stands to keep track of and store.
- Faster setup – Getting two stands in place goes quicker than four.
- Sufficient for minor jobs – Many small tasks only require access to one area of the vehicle.
- Less cost – Two stands are cheaper to purchase than four.
For routine maintenance like oil changes that only involve raising the front or the back, two jack stands under the front or rear jacking points appears adequate. The simplicity of two stands is appealing for many automotive hobbyists who don’t want the hassle of extra equipment.
Why Two Stands May Not Be Enough
However, there are some issues with relying on only two jack stands to support a vehicle. Here are some of the downsides:
- No side support – With two stands only under each end, the sides of the vehicle have no support. This creates the risk of the vehicle slipping or tilting sideways.
- Diagonal instability – The vehicle may rock diagonally without all four corners supported.
- Shift in weight – If someone gets into the vehicle or climbs around it, the weight distribution can shift.
- No backup support – If one stand fails, the other must hold all the vehicle’s weight.
- Risk of falling – Using all four stands greatly reduces the risk of the vehicle falling.
While two jack stands may hold the endpoints, vehicles can sway and rock if the sides are not also supported. The diagonal axis should be secured as well. Additionally, if something causes one stand to fail, the remaining stand must then bear the entire load. Four jack stands means each one only has to hold a portion of the total weight. Losing one of four stands is safer than losing one of two.
Factors to Consider
So should you use two jack stands or four? Here are some important factors to help determine the best amount of support:
The Vehicle’s Weight
Heavier vehicles require more support to hold them safely and prevent tipping. Large trucks, full-size vans, and SUVs can put significant force on just two jack stands. Using four stands helps distribute the load better. For smaller cars and lightweight vehicles, two jack stands may be adequate if positioned properly.
The Jobs Being Performed
Certain automotive jobs require access underneath the entire vehicle. In these cases, four jack stands allow you to safely raise the whole car or truck evenly. Jobs like transmission removal or oil pan gasket replacement need full undercarriage access. The vehicle must be fully supported on all sides.
For jobs involving just one end, like brake services, two stands under the working end may work. Although using four stands provides an added layer of protection in case something shifts unexpectedly.
Using Jack Stands on an Incline
Parking on an incline or slope increases the risk of the vehicle slipping or sliding on jack stands. Even with the parking brake set, gravity can still cause movement. Using four jack stands helps counter this, supporting all sides and corners. This prevents rolling or tipping downhill.
Supporting Both Sides
The vehicle’s weight should be balanced evenly on both sides. With only two stands, the tendency is to place them on the driver’s side for convenience. However, this leaves the passenger side without direct support. Four stands allow supporting both sides of the front and rear.
Using Wheel Chocks
Chocking the wheels remaining on the ground adds further stability. But chocks alone are not enough—jack stands must support the vehicle’s weight. Chocks can supplement stands, not replace them. Even with chocks, use four jack stands if possible.
Working Under the Vehicle
The greater the risk involved, the more support needed. If you need to position yourself under the elevated vehicle, use four jack stands for maximum safety. Never rely on just two contact points to support a vehicle if you’ll be underneath it.
Using Jack Stands Safely
Proper placement and setup of jack stands helps ensure the best support and safety, regardless of whether you use two or four. Here are some key jack stand safety tips:
- Use stands rated for your vehicle’s weight.
- Always use stands in pairs, never just one.
- Set stands only on flat, solid surfaces.
- Beware of settling stands on asphalt on hot days.
- Position stands directly under jacking points.
- Make sure the stand’s saddle grips the frame, not body panels.
- Double check that the stand’s ratchet or pin is fully engaged.
- Chock all wheels remaining on the ground.
- Rock the vehicle after setting to check stability.
- Use wheel ramps for additional support if needed.
Also, be sure to completely lower the jack once the stands are supporting the weight. Leaving a jack under the vehicle can lead to instability. Rubber jack stand pads help prevent slipping and provide a more secure grip.
Using Jack Stand Extensions
An alternative to using multiple jack stands is attaching extensions that widen the base. Extensions screw into the tops of stands, extending their reach on all sides. One stand with a large extension can support the side or end of a vehicle as well as multiple stands.
Extensions allow customizing the width and configuration as needed. You can use two stands with extensions under the front and back to create a four-point support system. Extensions also help level stands on uneven surfaces. The disadvantage is the added cost compared to buying more stands.
Using Ramps with Jack Stands
For very large vehicles like trucks and SUVs, wheel ramps combined with jack stands helps improve stability. Ramps provide a gently sloping platform to drive the vehicle up onto before jacking and placing stands. This gets the weight partially supported by the ramps.
Park the tires on the flats of the ramps after lifting on the stands. The ramps help carry the weight and minimize rocking or shifting on the stands. Make sure the stands are under the manufacturer jacking points, not just under the ramps. And chock the ramped wheels to prevent rolling.
Using a Vehicle Lift
The most secure and stable option is an automotive lift that raises the whole vehicle evenly from below. No jack stands are required with a lift. While home hobbyists likely don’t have a full garage lift, some smaller screw or scissor lifts that work with jack stands are available.
An option like the QuickJack portable lift can be used along with jack stands. Use the lift to raise the vehicle, then position jack stands under the manufacturer jacking points. Lower the lift to transfer the weight onto the stands while keeping some support from below. This mini lift + jack stand combo is popular for DIY enthusiasts.
Checking for Support Issues
After lifting on jack stands, check that all support points are secure before going under the vehicle. Look for:
- Tilting – Suspension should be level, not tilting.
- Twisting – Body should not be twisted at an angle.
- Binding – Doors should open and close normally.
- Rolling – Vehicle shouldn’t move when rocked.
- Creaking – No unusual sounds when shaken.
Issues like these indicate a problem with stand placement or vehicle stability. Resolve any support problems before working underneath.
Using Jack Stands on Other Vehicles
The same principles apply when using jack stands on vehicles other than cars and trucks. Support all four corners evenly:
- Motorcycles – Use one stand under each end.
- ATVs – Two stands minimum, four optimal.
- Trailers – Support the corners or along the frame.
- RVs – Lift each axle or wheel set individually.
- Machinery – Follow the maintenance manual directions.
Regardless of the vehicle, allowing it to tilt or pivot risks collapse and injury. Use enough stands to keep the unit completely stable.
Inspecting Jack Stands
Prior to each use, jack stands should be inspected for any cracks, damage, or missing parts. Look for:
- Cracked or bent bases
- Bent support posts
- Smooth ratchet teeth
- Broken or missing pins
- Loose or missing handles
- Damaged saddle parts
- Loose leg adjustments
- Missing extension components
Stands with any damage should not be used to support a lifted vehicle. Also confirm the stand is designed to handle your vehicle’s weight. Inspect stands periodically even if not used, as cracks can develop over time.
Relieving Pressure Safely
When work is complete, relieve pressure on the jack stands carefully as you lower the vehicle. Loosen fasteners in a criss-cross pattern to bring the weight down evenly. On each stand:
- Loosen the ratchet/pin slowly.
- Raise the bar slightly to loosen pressure.
- Repeat to gradually transfer weight.
- Lower the stand only as much as needed to install the jack.
- Raise the jack to contact but not lift.
- Finish lowering the stand while monitoring the jack.
Go slow to prevent sudden weight shifts. Use the jack to gradually take over the load as stands are removed. Only lower fully once all work is done.
Conclusion
Two jack stands may be sufficient when only lifting one end of a vehicle for minor tasks. But using four stands provides significantly more protection from crush injuries. The small added cost and effort of two additional stands pays off in improved stability. For any job requiring being under the vehicle, four stands should always be used. One failed stand can leave the other unable to bear the vehicle’s full weight.
There are exceptions where two stands are adequate based on the vehicle weight and job. But at a minimum, support opposite ends on the same side rather than diagonally. Extensions or ramps can also improve stability when fewer stands must be used. Regardless, always check for secure support before going underneath. Taking the time to use jack stands properly avoids a world of hurt.
