Vehicle jack stands come in various weight capacities to accommodate different types of vehicles. The most common weight capacities are: 1. **2-ton (4,000 lbs):** Suitable for small cars and compact vehicles. 2. **3-ton (6,000 lbs):** Ideal for mid-sized sedans, small SUVs, and light trucks. 3. **6-ton (12,000 lbs):** Designed for larger SUVs, full-size trucks, and vans. 4. **12-ton (24,000 lbs):** Used for heavy-duty trucks and commercial vehicles. When selecting jack stands, it's crucial to consider the total weight of the vehicle and ensure the stands can support it safely. Always use jack stands in pairs, and never exceed their rated capacity.

1. **Weight Capacity**: Ensure the jack stands can support the weight of your vehicle. Check your vehicle's gross weight and choose stands with a capacity exceeding this weight. 2. **Height Range**: Consider the lift height you need. The stands should accommodate the height your vehicle will be lifted to, ensuring stability and safety. 3. **Material**: Opt for durable materials like steel or aluminum. Steel is heavier and more robust, while aluminum is lighter and easier to handle. 4. **Base Design**: Look for a wide base for stability. A larger base provides better support and reduces the risk of tipping. 5. **Locking Mechanism**: Choose stands with a reliable locking mechanism, such as a pin or ratchet system, to securely hold the vehicle in place. 6. **Adjustability**: Ensure the stands are adjustable to different heights to accommodate various lifting needs. 7. **Certification**: Check for safety certifications like ASME (American Society of Mechanical Engineers) to ensure the stands meet safety standards. 8. **Brand Reputation**: Consider reputable brands known for quality and reliability in automotive tools. 9. **Reviews and Recommendations**: Read user reviews and seek recommendations to gauge the performance and reliability of the jack stands. 10. **Price**: Balance cost with quality. While budget options exist, investing in a reliable set ensures safety and longevity. 11. **Compatibility**: Ensure the stands are compatible with your vehicle type, whether it's a car, SUV, or truck. 12. **Storage and Portability**: Consider the ease of storage and portability if you need to transport the stands frequently.

Tripod jack stands are generally considered better for stability compared to tower jack stands. The three-legged design of tripod stands provides a wider base of support, which helps distribute weight more evenly and reduces the risk of tipping over. This design is particularly advantageous on uneven surfaces, as the three points of contact can adapt more easily to variations in the ground. Tower jack stands, on the other hand, typically have a four-legged design. While they can offer good stability on flat, even surfaces, they are more susceptible to wobbling or tipping if the ground is uneven. The four legs need to be perfectly aligned to ensure stability, which can be a disadvantage in less-than-ideal conditions. Additionally, tripod stands are often lighter and easier to maneuver, making them more convenient for quick setups and adjustments. However, tower stands can sometimes offer higher weight capacities and adjustable heights, which might be beneficial for certain applications. In summary, for general use and especially on uneven surfaces, tripod jack stands are often preferred for their superior stability. However, the choice between tripod and tower jack stands may also depend on specific needs such as weight capacity and height requirements.

No, jack stands should not be used on uneven surfaces. Jack stands are designed to provide stable support for a vehicle when it is lifted off the ground. For them to function safely, they require a flat, stable, and solid surface. Using jack stands on uneven surfaces can lead to instability, increasing the risk of the vehicle shifting or falling, which can cause injury or damage. Always ensure the ground is level and firm, such as concrete or asphalt, before using jack stands. If you must work on an uneven surface, consider relocating the vehicle to a more suitable area or using alternative methods to ensure stability and safety.

1. **Preparation**: Park the vehicle on a flat, stable surface. Engage the parking brake and chock the wheels that will remain on the ground to prevent rolling. 2. **Lifting the Vehicle**: Use a hydraulic floor jack to lift the vehicle. Refer to the vehicle's owner manual to locate the recommended jacking points, usually reinforced areas on the vehicle's frame or undercarriage. 3. **Positioning Jack Stands**: Once the vehicle is lifted to the desired height, place the jack stands under the vehicle. Use the vehicle's manual to identify the correct support points for the jack stands, which are often near the jacking points but not the same. These are typically on the vehicle's frame or designated reinforced areas. 4. **Adjusting Jack Stands**: Adjust the height of the jack stands to match the lifted height of the vehicle. Ensure the stands are locked securely in place. 5. **Lowering the Vehicle**: Slowly lower the vehicle onto the jack stands by carefully releasing the hydraulic jack. Ensure the vehicle is stable and securely resting on the stands before removing the jack completely. 6. **Stability Check**: Gently push the vehicle to ensure it is stable and does not wobble. If there is any movement, reposition the jack stands and check the placement again. 7. **Safety Precautions**: Never work under a vehicle supported only by a jack. Always use jack stands for safety. Ensure the stands are on a solid surface and not on soft ground or inclined surfaces. 8. **Final Check**: Double-check that all stands are properly positioned and locked before proceeding with any work under the vehicle.