How Do Wheelbase And Tire Size Affect Your 4-Link Suspension Design?

19 October 2022
 Categories: , Blog

Building a 4-link suspension for your off-roading rig is a fun project that can improve your vehicle's practical ability to handle rough terrain. However, it's crucial to remember that custom 4-link suspensions are more than just bolt-on modifications. Building a new suspension for your rig is a significant engineering project requiring careful design, installation, testing, and tuning.

With any project of this scope, planning and design are often the most important phases. Getting your design right will help you choose the right parts and avoid problems down the line, making your suspension more reliable and safer. If you're just starting, the relationship between the wheelbase and your intended tire size is one of the most critical factors to understand.

Why Does It Matter?

There's no getting around it: designing a custom suspension requires a bit of math. You'll need to consider the geometry of your rig's frame as well as your goals and intended endpoint. Your target tire size is crucial because it affects your vehicle's center of gravity. A higher center of gravity can reduce stability, especially in off-roading situations.

Conversely, your vehicle's wheelbase can improve stability. A longer wheelbase typically means more stability which, in turn, can allow you to run taller lifts and larger tires. Unfortunately, you probably won't be able to affect your wheelbase unless you're building a custom rig from scratch or planning on substantial modifications to your truck.

Ultimately, the link length, angle, and other design considerations for your 4-link setup will depend on your intended height. You can use your wheelbase as a guide when deciding on your intended tire size. You can plan for larger tires if you run a rig with a longer wheelbase. On the other hand, shorter wheelbase vehicles should stick with smaller tire diameters to keep their center of gravity low.

How Will These Factors Affect Your Design?

Once you know your target tire size, you can begin to design your 4-link suspension in earnest. Factors affected by your final tire size include the spacing between upper and lower links (axle link separation), lower link angle, and link lengths. Since axle link separation typically depends on tire diameter, a larger tire size will result in a longer lower link to connect to the chassis.

Of course, these factors are only the very first considerations you'll need to make when designing a 4-link suspension. You'll also need to balance relative upper and lower link lengths based on your intended usage (fully off-road or mixed), how much stability you need, and the materials you intend to use. These considerations will ultimately allow you to begin working on your first-pass 4-link design. 

For more information, contact a company like Rock Slayer Off Road Inc.