RockShox Suspension Calculator

Find Your Perfect Settings

Suspension Setup Guide

Getting your suspension dialed is crucial for performance, control, and comfort on the trail. This guide will help you understand the key elements and how to use the calculator to achieve optimal results.

Understanding Your RockShox Suspension

RockShox offers a wide range of suspension components, from forks to rear shocks, designed to enhance your riding experience. Each component is engineered with specific technologies to absorb impacts, maintain traction, and provide a smooth, controlled ride. Proper setup ensures that your suspension works with you, not against you.

Why Suspension Setup Matters

• Traction: Well-set suspension keeps your tires glued to the ground, improving grip in corners and on climbs.
• Control: Balanced suspension prevents unwanted dives under braking or excessive squatting under acceleration, giving you more confidence.
• Comfort: Absorbing bumps reduces fatigue, allowing you to ride longer and harder.
• Efficiency: Properly tuned suspension can improve pedaling efficiency by reducing energy loss through unwanted suspension movement.

RockShox Suspension Calculator: Formula and Mathematical Explanation

The RockShox Suspension Calculator uses a combination of established principles and manufacturer-recommended guidelines to provide a starting point for your suspension setup. The core recommendations are derived from your weight, the type and travel of your suspension, and your intended riding style and terrain.

Primary Formula (Simplified):

The calculator primarily focuses on recommending initial air pressure based on rider weight and suspension volume. Rebound and compression settings are then adjusted based on riding style and terrain, referencing typical ranges.

Air Pressure Calculation Basis:

Air Pressure (PSI) ≈ Rider Weight (kg or lbs) * Pressure Multiplier

The ‘Pressure Multiplier’ is an empirically derived value that varies based on suspension type (fork vs. shock), travel, and even specific RockShox models (though this calculator uses general estimations). For air shocks, stroke length is also a factor in determining sag, which indirectly influences recommended pressure.

Sag Calculation (for Rear Shocks):

Sag (%) = (Rider Weight * SAG_Factor) / (Shock Stroke * Spring_Rate_Factor) * 100

While not directly displayed, the recommended air pressure aims to achieve a target sag (e.g., 25-35% for trail/enduro). The calculator simplifies this by providing a direct pressure recommendation.

Rebound Damping:

Rebound controls how quickly the suspension extends after being compressed. It’s typically set based on terrain and rider preference, often starting in the middle and adjusting.

Compression Damping:

Compression controls how quickly the suspension compresses. It can be adjusted to provide more support on rough terrain or to firm up the suspension for climbing.

Variables Used:

Suspension Calculator Variables

Variable	Meaning	Unit	Typical Range / Options
Rider Weight	Total weight of the rider including gear (helmet, pack, etc.)	kg or lbs	10 – 150 kg / 22 – 330 lbs
Suspension Type	Type of RockShox component	N/A	Air Fork, Air Shock
Fork Travel	Maximum distance the fork can compress	mm	80 – 200+ mm
Shock Travel	Maximum distance the rear shock can compress	mm	35 – 95+ mm
Shock Stroke	The physical length the shock shaft travels	mm	20 – 75+ mm
Riding Style	Type of cycling discipline	N/A	Trail, Enduro, Downhill, Cross Country
Terrain Type	Surface characteristics of the trails	N/A	Smooth, Mixed, Rough
Recommended Air Pressure	Initial target air pressure for the suspension component	PSI	Dynamic (based on inputs)
Recommended Rebound Setting	Initial target setting for rebound damping	Clicks / Turns	Dynamic (based on inputs, typically ~50% open)
Recommended Compression Setting	Initial target setting for compression damping	Clicks / Turns	Dynamic (based on inputs, often neutral)

Practical Examples

Let’s see how the RockShox Suspension Calculator works with real-world scenarios.

Example 1: Trail Rider Setting Up a Fork

Inputs:

• Rider Weight: 75 kg (including gear)
• Suspension Type: Air Fork
• Fork Travel: 150 mm
• Riding Style: Trail
• Terrain Type: Mixed (Roots, Rocks, Gaps)

Calculator Output (hypothetical):

• Recommended Air Pressure: 85 PSI
• Recommended Rebound Setting: 8 Clicks from fully closed
• Recommended Compression Setting: Mid-level (3 out of 6 clicks)

Interpretation: For a 75kg trail rider on a 150mm fork encountering mixed terrain, the calculator suggests starting with 85 PSI. The rebound is set moderately open to allow the wheel to follow the ground. Compression is set in the middle to balance support and small bump sensitivity. This rider should then test ride and fine-tune based on feel, potentially adding/reducing pressure slightly or adjusting damping.

Example 2: Enduro Rider Setting Up a Rear Shock

Inputs:

• Rider Weight: 90 kg (including gear)
• Suspension Type: Air Shock
• Shock Travel: 65 mm
• Shock Stroke: 40 mm
• Riding Style: Enduro
• Terrain Type: Rough (Chunky Rocks, Big Drops)

Calculator Output (hypothetical):

• Recommended Air Pressure: 210 PSI
• Recommended Rebound Setting: 10 Clicks from fully closed
• Recommended Compression Setting: Open/Plush (1 out of 6 clicks)

Interpretation: This heavier rider (90kg) on an enduro bike needs significant support. The calculator recommends a higher pressure (210 PSI) to achieve appropriate sag for the 65mm travel / 40mm stroke shock. For rough enduro terrain, rebound is set slightly slower (more clicks closed) to control the suspension on successive hits, and compression is kept open for maximum compliance and traction on technical descents. This rider might also consider volume spacers to prevent bottom-outs.

How to Use This RockShox Suspension Calculator

Using the RockShox Suspension Calculator is straightforward. Follow these steps to get your initial suspension settings:

1. Enter Rider Weight: Accurately weigh yourself with all your riding gear (helmet, pack, water, tools, etc.). This is the most critical input for determining pressure.
2. Select Suspension Type: Choose whether you are setting up a front fork or a rear shock.
3. Input Suspension Dimensions:
   • For Forks: Enter the total travel in millimeters (e.g., 130mm, 160mm).
   • For Rear Shocks: Enter both the shock’s total travel (e.g., 60mm, 75mm) and its stroke length (the physical shaft travel, often found printed on the shock body or in its specs). These are different but both crucial for shock setup.
4. Choose Riding Style: Select the discipline that best fits your typical riding (e.g., Trail, Enduro, Downhill). This influences damping recommendations.
5. Specify Terrain Type: Select the terrain you most commonly ride on. This also affects damping settings, with rougher terrain generally requiring more open damping.
6. Click ‘Calculate Settings’: The calculator will process your inputs and provide recommended starting points for air pressure, rebound, and compression.

Reading and Applying the Results

• Recommended Air Pressure: This is your starting point. It’s crucial to verify this pressure with a reliable shock pump.
• Recommended Rebound Setting: This is usually expressed in clicks from fully closed (slowest) or fully open (fastest). Start with the recommended setting.
• Recommended Compression Setting: Similar to rebound, this indicates a starting point for low-speed compression adjustments.

Making Fine Adjustments

These are *starting points*. Every rider and bike is unique. After applying the recommended settings:

• Test Ride: Ride your usual trails. Pay attention to how the suspension feels during impacts, cornering, and pedaling.
• Adjust Pressure: If you feel harsh on big hits, you might have too much pressure or need more damping. If you’re using full travel too easily (bottoming out), increase pressure slightly or add volume spacers. If you don’t use enough travel, consider reducing pressure slightly. Aim for 25-35% sag on forks and 30-35% on rear shocks for trail/enduro use.
• Adjust Rebound: Too fast (pogo stick effect)? Add clicks (close). Too slow (packing down)? Remove clicks (open).
• Adjust Compression: Too much pedal bob? Add compression (firmer). Too harsh on small bumps? Reduce compression (more plush).

Always make one adjustment at a time and re-test.

Key Factors Affecting RockShox Suspension Results

While the calculator provides a solid baseline, several factors can influence your ideal suspension settings. Understanding these helps in fine-tuning:

1. Rider Weight (and Distribution): While we use total weight, how that weight is distributed (e.g., heavy backpack vs. light jersey) can affect feel. Aggressive body position can also bias weight forward.
2. Suspension Service History: Freshly serviced suspension with clean oil and proper lubrication will perform optimally. Old, dirty, or low oil can lead to inconsistent performance and less effective damping.
3. Air Spring Volume (Tokens/Spacers): Many RockShox forks and shocks allow you to add or remove volume spacers. Adding spacers makes the air spring more progressive (resists bottoming out more strongly towards the end of travel), while removing them makes it more linear. This is key for fine-tuning bottom-out resistance without drastically changing pressure.
4. Tire Pressure and Casing: Tire pressure significantly impacts how impacts are felt before they even reach the suspension. Lower tire pressures can offer more compliance but increase the risk of pinch flats. Tire casing (e.g., EXO, DoubleDown, Super Gravity) also affects durability and damping characteristics.
5. Leverage Ratio of the Bike: For rear shocks, the bike’s suspension linkage (leverage ratio) dictates how the shock’s compression and travel are applied. Some bikes are more progressive than others, influencing the air pressure and volume spacer setup needed.
6. Damping Adjustments (Advanced): Beyond basic rebound and compression, some high-end RockShox units have separate high-speed compression (HSC) and high-speed rebound (HSR) adjustments. These are critical for managing big impacts and fast, successive hits, especially in downhill and enduro riding.
7. Riding Terrain Nuances: Even within categories like “rough,” the specific type of roughness matters. Are they braking bumps, chattery rocks, or big square-edged hits? Adjustments might differ.
8. Personal Preference: Ultimately, how you like your suspension to feel is paramount. Some riders prefer a firmer, more supportive ride, while others favor a plush, glued-to-the-ground feel.

Frequently Asked Questions (FAQ)

Q1: What is ‘sag’ and why is it important for my RockShox suspension?

Sag is the amount your suspension compresses under your body weight when you’re in a neutral riding position. It’s crucial because it ensures your suspension is positioned in its optimal travel range to absorb bumps effectively, both upward (compression) and downward (extension). For trail and enduro, 25-35% sag is common.

Q2: Should I use PSI or Bar for my RockShox suspension?

The calculator defaults to PSI (Pounds per Square Inch), which is the standard unit used by RockShox and most North American riders. You can convert to Bar if needed (1 Bar ≈ 14.5 PSI).

Q3: My calculator says 70 PSI, but my friend with similar weight uses 90 PSI. Why?

There are many reasons: different bike leverage ratios, different volume spacer configurations, different riding styles, tire pressure differences, or simply personal preference. The calculator provides a starting point; your friend’s settings might be fine-tuned for their specific setup.

Q4: How do I set rebound on my RockShox fork or shock?

Start with the recommended clicks. Ride the bike. If it feels like a pogo stick after hitting bumps, turn the rebound knob clockwise (more damping, slower extension). If the suspension “packs down” (doesn’t return quickly enough, feeling harsh on consecutive hits), turn counter-clockwise (less damping, faster extension).

Q5: What’s the difference between compression and rebound damping?

Rebound controls how quickly the suspension extends *after* being compressed. Compression controls how quickly the suspension compresses *under load*. Low-speed compression affects pedal bob and G-outs, while high-speed compression handles big impacts.

Q6: Can I use this calculator for coil-sprung suspension?

No, this calculator is specifically designed for RockShox air suspension components. Coil springs use physical springs of different rates, and their setup involves selecting the correct spring weight, not air pressure.

Q7: Do I need to use RockShox-specific setup tools?

While RockShox provides specific service tools for maintenance, you don’t necessarily need special tools for basic setup. A reliable shock pump with a gauge and a standard Allen key (for compression/rebound knobs) are usually sufficient. A tape measure or ruler helps check sag.

Q8: What if my suspension feels harsh even with the recommended settings?

Harshness can be due to insufficient rebound damping (packing down), too much low-speed compression, or simply needing more air pressure/volume spacers to prevent bottoming out harshly. Check your air pressure first, then experiment with rebound and compression adjustments. Ensure your suspension has been recently serviced.

Related Tools and Internal Resources

• RockShox Suspension Calculator: Use our advanced tool to find your ideal settings.
• Mountain Bike Suspension Tuning Guide: A comprehensive resource for advanced adjustments.
• Understanding Bike Geometry: How frame design affects suspension performance.
• How to Choose the Right MTB Fork: Factors to consider when buying new suspension.
• Rear Shock Technology Explained: Deep dive into different shock designs.
• MTB Tire Pressure Calculator: Optimize your tire pressure for grip and comfort.
• Dropper Post Setup Guide: Get your dropper post height just right.