The stroke is the maximum length by which the spring can be compressed and must always match the stroke of the shock absorber used.
When the stroke of the spring is smaller than the stroke of the shock, both the spring and the shock can be damaged. When the stroke of the spring is greater than the stroke of the shock, it must be ensured that the spring is not too long. Otherwise installation problems may occur.

The spring rate indicates how much the force per travel/deflection of a spring increases.
The spring rate is usually specified in N/mm (newtons per millimetre) or lbs/inch (pounds per inch).
The spring rate results from several components, such as wire thickness, diameter, untensioned length, number of coils and material properties.
To select the correct spring rate, it is important to consider the spring rate recommendation of the bicycle manufacturer as well as the intended use and the rider’s weight.
Your specialist dealer will be happy to help you make the right choice and advise you on the correct spring rate.

The stroke of the spring is not directly related to the untensioned / free length of the spring. Depending on the material, stroke and spring rate, the length can vary and is therefore not directly relevant.
Appropriate pom spacers can be used and combined to compensate for any required length – ask your specialist dealer about this.

“Sag” is the suspension travel that occurs when the rider’s body weight acts on the bike/suspension elements when stationary.
If there is too little sag, the bike has too little grip; if there is too much sag, the handling becomes wobbly.
Accordingly, the correct sag must be taken into account and adjusted for each spring/shock absorber combination in order to achieve an optimally tuned bike for the respective rider and intended use.