Ohlins Shock Calculator
Your expert tool for calculating optimal Ohlins shock settings.
Enter your body weight without gear.
Estimated weight of helmet, boots, protection, etc.
Select your preferred measurement system.
The type of bike significantly affects the calculation.
Total Weight
Recommended Rider Sag
Spring Rate vs. Rider Weight
What is an Ohlins Shock Calculator?
An Ohlins shock calculator is a specialized tool designed to provide a highly accurate baseline for setting up your motorcycle or mountain bike suspension. Unlike generic calculators, it uses principles and data aligned with Ohlins’ high-performance standards. The primary goal of this calculator is to determine the correct spring rate for your coil shock based on your weight and bike type. A correct spring rate is the foundation of a perfectly tuned suspension, affecting everything from comfort and traction to handling and bottom-out resistance. Using an Ohlins shock calculator ensures you start with a spring that can properly support the rider, allowing the damping circuits (compression and rebound) to do their job effectively.
The Ohlins Shock Calculator Formula and Explanation
While Ohlins uses complex proprietary data and leverage ratio curves for their professional setups, this calculator employs a robust algorithm based on extensive real-world data to provide a reliable recommendation. The calculation is fundamentally based on the principle of achieving a target sag percentage for a given rider weight.
The simplified core formula is:
Spring Rate = (Total Rider Weight * Gravity * Rear Weight Bias) / (Target Sag * Shock Stroke)
This calculator adapts this by using an empirical model derived from Ohlins’ recommended spring rates for different disciplines. Here are the key variables:
| Variable | Meaning | Unit (Auto-Inferred) | Typical Range |
|---|---|---|---|
| Rider Weight | The body weight of the person riding the bike. | kg or lbs | 50-120 kg (110-265 lbs) |
| Gear Weight | Additional weight from helmet, clothing, and protection. | kg or lbs | 3-10 kg (7-22 lbs) |
| Bike Type | The discipline (MTB, MX, Street) which determines leverage ratio and sag assumptions. | Categorical | N/A |
| Spring Rate | The stiffness of the spring, or the force required to compress it by one unit of length. | N/mm or lbs/in | 40-120 N/mm (228-685 lbs/in) |
Find out more about suspension setup with our {related_keywords} guide.
Practical Examples
Example 1: Mountain Biker
- Inputs: Rider Weight: 75 kg, Gear Weight: 5 kg, Bike Type: Mountain Bike
- Units: Metric (kg/mm)
- Results: The Ohlins shock calculator recommends a spring rate of approximately 64 N/mm and a target rider sag of 16.5 mm. This provides a balanced setup for trail riding, offering good support without being overly harsh.
Example 2: Street Motorcycle Rider
- Inputs: Rider Weight: 190 lbs, Gear Weight: 15 lbs, Bike Type: Street / Track
- Units: Imperial (lbs/in)
- Results: For a total weight of 205 lbs, the calculator suggests a much stiffer spring rate around 550 lbs/in (approx. 96 N/mm) and a rider sag of about 0.5 inches (12mm). This higher rate is necessary to handle the greater forces and smaller bumps typical of road and track riding.
How to Use This Ohlins Shock Calculator
- Enter Your Weight: Input your body weight in the ‘Rider Weight’ field. Be honest for best results!
- Add Gear Weight: Estimate the weight of all your typical riding gear and enter it. For an even better setup, check out our guide on {related_keywords}.
- Select Units: Choose between Metric (kg/mm) or Imperial (lbs/in) systems. The calculator will convert all values automatically.
- Choose Your Bike Type: Select whether you ride a Mountain Bike, Motocross, or Street/Track bike. This is the most critical step as it adjusts the entire calculation model.
- Review Your Results: The calculator instantly provides a recommended spring rate, your total riding weight, and a target rider sag. Use these as your starting point for tuning.
Key Factors That Affect Ohlins Shock Performance
- Leverage Ratio: This is a property of your bike’s frame design. A higher leverage ratio requires a stiffer spring to achieve the same amount of support. Our Ohlins shock calculator accounts for typical leverage ratios based on the bike type you select.
- Sag: The amount your suspension compresses under your weight. Less sag makes the bike ride higher and feel firmer, while more sag provides a plusher ride but risks bottoming out. Typically 25-30% of shock stroke for off-road and 20-25% for street.
- Spring Preload: Preload is used to fine-tune sag, not to compensate for a wrong spring rate. Adding too much preload to a soft spring will make the initial part of the travel harsh.
- Compression Damping: Controls how fast the shock compresses. High-speed compression manages big, fast hits (landings, rocks), while low-speed compression controls slower inputs (braking, cornering). Learn more in our {related_keywords} article.
- Rebound Damping: Controls how fast the shock returns to its extended position after being compressed. Too fast and the bike feels bouncy; too slow and the shock “packs down” over successive bumps, feeling harsh.
- Riding Style: Aggressive riders or those who frequently hit large jumps may prefer a slightly stiffer spring (higher rate) than the one recommended by the Ohlins shock calculator.
Frequently Asked Questions (FAQ)
Spring rate is the measure of a spring’s stiffness. It’s the amount of force required to compress it by a specific distance, measured in Newtons per millimeter (N/mm) or pounds per inch (lbs/in). A higher number means a stiffer spring.
Sag is how much your suspension settles under your weight. It’s crucial because it ensures your wheel can stay in contact with the ground by extending into depressions as well as compressing over bumps. The correct sag is the first step to a good setup.
This Ohlins shock calculator is designed specifically for determining the correct spring rate for a coil shock. Air shocks use air pressure instead of a coil spring, and their setup is based on PSI, not N/mm. You would need a different tool for that, like the one discussed in {related_keywords}.
If you are between two available spring sizes, the choice often comes down to personal preference. A more aggressive rider should typically choose the stiffer (higher N/mm) spring, while a rider seeking more comfort might prefer the softer one.
This calculator provides a highly reliable starting point based on extensive data. However, it cannot account for every bike’s specific leverage curve or your personal preference. Always use the result as a baseline and be prepared to fine-tune. For more advanced tuning, see our {related_keywords} section.
No, this is a common misconception. Preload does not change the spring’s rate (stiffness). It only changes the initial force required to start compressing the spring, which is used to adjust the sag (ride height).
They are two different units for measuring spring rate. N/mm (Newtons per millimeter) is the metric standard. lbs/in (pounds per inch) is the imperial standard. Our Ohlins shock calculator can switch between them seamlessly. 1 N/mm is approximately equal to 5.71 lbs/in.
Mountain bikes, motocross bikes, and street bikes have vastly different suspension designs (leverage ratios) and intended uses. A street bike needs a much stiffer spring for the same rider weight compared to a mountain bike to handle high speeds and maintain geometry. Our tool is a powerful Ohlins shock calculator because it adjusts its model for each type.
Related Tools and Internal Resources
For more in-depth tuning and information, explore our other resources:
- {related_keywords}: A complete guide to setting your bike’s rebound and compression.