Shock absorber springs

Springs are a key component of coil shocks, used primarily in downhill (DH), enduro and freeride bikes. Their job is to absorb shocks and provide consistent support when riding over rough terrain. Unlike air shocks, coil spring systems use a steel or titanium coil spring, which offers consistent performance without significant overheating or changing characteristics.

What is the main characteristic of the spring used in spring shock absorbers?

The main characteristics of the spring in the shock absorber are:

Linear characteristic: equal resistance throughout the entire stroke (ideal for aggressive riding)
High sensitivity: excellent ground following at the beginning of the stroke
Easy maintenance: the spring does not need regular pressurization
Greater weight compared to air systems (especially steel versions)

How to choose the right spring?

Selecting the right spring is essential for the function of the entire bicycle. Two main values are important:

Stiffness/Rate – spring stiffness
- It is given in units of lb/in (or N/mm)
- Indicates how much force is required to compress the spring by 1 inch (or mm)
- For example, a spring with a value of 400 lb/in requires 400 pounds of force to compress 1 inch.
- Typical values: 300 – 550 lb/in (depends on rider weight and riding type)
- 60–70 kg: 350–400 lb/in
- 70–85 kg: 400–450 lb/in
- 85–100 kg 450–500 lb/in
- 100+ kg: 500–600 lb/in
Spring length and diameter
- Must match the specific shock absorber (e.g. 216x63 mm, 230x65 mm, etc.)
- Diameters are commonly: 36 mm (RockShox, Fox) or 38 mm+ (some DVO, Öhlins)
- Spring length (free length) – the spring must fit the shock absorber, but not be too long (so that it can be installed)

Other tips when choosing a spring

Progressive coil: Some springs have a progressive characteristic, suitable for frames without their own progression.
Titanium springs: Lighter than steel, but significantly more expensive
Preload: The spring should only be set to a slight preload – if you have to turn the screw more than 2-3 turns, your spring is too soft.

Can I use different brands of springs on a shock absorber from another manufacturer?

Yes, but only if they have the same dimensions and a compatible diameter. For example, Fox, RockShox and Cane Creek often use different diameters.

How do I find out what travel my shock absorber has?

The shock travel is stated in millimetres (e.g. 65 mm) or inches (e.g. 2.5”). You can find it on the shock's label or in the bike's technical specifications.