MTB steel springs for shocks and forks

MTB Springs: Steel springs for shocks and coil forks

MTB springs are the steel coils found in coil shocks and coil forks. Their spring rate determines how much force is required to compress the spring—and therefore how deep your bike sags under your weight. At MTB-Raceshop, you will find springs from WPS, PUSH, Öhlins, and Vorsprung.

Unlike an air spring, you cannot change the stiffness with a pump: if the spring rate is not right, you need a different spring. That is why it is worth calculating the spring rate before purchasing.

Which spring do you need?

Shock springs

For coil shocks: WPS SiCrmade of silicon-chrome steel in 25 lb/in increments with ±2% tolerance, PUSH Hypercoilalso in 25 lb/in increments, and Öhlins springsin 4 N/mm increments for the TTX22M.

Fork springs

For coil forks and conversions: Öhlins springsfor RXF36, RXF38, and DH38, the Spring Assemblyfor the PUSH Nine.One (30–60 lbs), and Smashpot springsfrom Vorsprung (25–80 lbs).

Adapters and extenders

The WPS Spring Adaptersfit 38 mm springs onto 35 or 36 mm spring seats. Spring Extenderslengthen the spring by 21 or 28 mm for the correct preload range.

Understanding spring rate: lb/in, N/mm, stroke, and inner diameter

The spring rate indicates how much force the spring requires per distance. lb/in (pounds per inch) is standard; Öhlins also specifies N/mm. A 450 lb/in spring requires 450 pounds of force to compress one inch (25.4 mm).

• Conversion: 1 lb/in equals 0.175 N/mm. Thus, 450 lb/in is about 79 N/mm, and 100 N/mm is about 571 lb/in.
• Stroke: The spring must be designed for the stroke of your shock. WPS SiCr springs are available for 47.5–65 mm and 65–75 mm strokes, and the Öhlins spring with 115 mm length is for up to 57 mm stroke.
• Inner diameter: The spring must fit the spring seat. The WPS SiCr has a 38 mm diameter; adapters are available for smaller seats.
• Fork springs have significantly lower values: for example, Öhlins assigns 50 lb/in for the RXF36 to a rider weight of approximately 73 kg.

Calculating spring stiffness with the Spring Calculator

The appropriate spring rate depends on rider weight with gear, bike weight, desired SAG, travel, stroke, and rear suspension kinematics. The kinematics are contained in the leverage ratio: travel divided by stroke—for 160 mm of travel and 65 mm of stroke, that is about 2.5.

Our Spring Calculator computes a starting value in lb/in and N/mm from this—with presets for enduro and downhill bikes and, if requested, a ratio curve per millimetre of stroke. You confirm the final value with a SAG measurement and a test ride.

To the MTB spring rate calculator

When installing, remember: preload only ensures that the spring sits without play; you adjust the SAG via the spring rate. Permissible preload is stated in your shock's manual. Need assistance? During Setup Coachingin Dällikon, we will adjust the spring and SAG with you.

Frequently asked questions about MTB springs

How do I calculate the spring stiffness for my MTB shock?

You need your rider weight with gear, bike weight, travel, shock stroke, and the desired SAG. Our Spring Calculatoruses this to calculate a starting value in lb/in and N/mm. If the result falls between two springs, a SAG measurement on the bike will help you decide.

What does a spring rate of 450 lb/in mean?

lb/in stands for pounds per inch: a 450 lb/in spring requires 450 pounds of force to compress one inch (25.4 mm). In metric terms, that is about 79 N/mm. The higher the number, the stiffer the spring.

Which spring fits my shock?

In addition to the spring rate, the stroke and inner diameter must match: the spring must be designed for the full stroke and fit on the spring seat. Manufacturer springs fit their own shocks; for 38 mm springs like the WPS SiCr, there are adapters for smaller spring seats.

Is a titanium spring worth it?

A titanium spring is lighter than a steel spring with the same spring rate, but costs significantly more. A lightweight steel alternative is a spring made of silicon-chrome steel, such as the WPS SiCr.

What are suspension components on a mountain bike?

Suspension components refer to the suspension fork and shock, i.e., the parts with the spring and damping. The spring supports the weight, and the damping controls the movement. You can find forks and shocks in the Suspensioncategory.