Here are some general guidelines we’ve gathered from working on a wide variety of vehicles. We suggest using them as a starting point when considering your suspension setup. Professional builders, racers, and enthusiasts can also provide valuable insights.
Allow For Room to Move, But Don’t Over Do It
- A minimum of 4” of up travel and 4” of down travel is recommended for any off-roading.
- If you’re aiming for speed, 6” of up travel is a solid baseline.
- As up travel increases, both capability and comfort improve, but keep in mind that handling may suffer due to reduced spring rates and damping.
- It’s important to design your suspension based on the terrain you’ll encounter most often.
- If possible, aim for the rear up travel to be 25% more than the front.
- For rock crawlers, around 1/3 of the available travel should be up travel, while fast vehicles, including rock racers, tend to benefit from 2/3 of the travel being up travel.
Carefully Design Your Bottoming Control
- Air bumps are excellent for controlling bottoming out, but they can create harshness and banging sounds if they’re hit too often.
- Make sure to give your air bumps at least 3” of clearance in the front and 4” in the rear.
- The travel of your air bumps should be about 1/3 of your up travel or less.
- If space is tight and air bumps aren’t an option, foam urethane bump stops are a solid alternative.
- While foam urethane isn’t as tunable as air bumps, their progressive design offers a smoother, more comfortable feel when they’re contacted frequently near ride height.
- However, keep in mind that foam urethane is generally less durable.
Carefully Design Your Top Out Control
- Run limit straps, off-road shocks were not made to top out
- Some bypass shocks are exempt from this rule if designed to do so
Use Motion Ratios on Light Vehicles
- Motion ratios between 0.9 and 0.6 make shock tuning easier on lightweight vehicles.
- For these lighter rigs, it’s best to use a smaller (numerically) motion ratio.
- A lower motion ratio helps reduce the impact of shock friction.
- Keep in mind that mounting shocks at extreme angles isn’t an effective way to achieve the desired motion ratio.
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