The 12.51 has a 22 [mm] strut shaft.
The 12.52 has a larger strut shaft.
The 12.53 is an upsidedown strut construction.
This depends on the application, when the car is subjected to high side loads upgrading to a larger shaft is recommended. Contact us or a dealer if you need help choosing.
The 12.5x is featured with our 50-DA shaft, this allows you to fully operate only on the shaft/ only on the reservoir or a combination. With this feature you can adjust the amount of hysteresis.
The 12.3x is featured with our regular motorsport shaft with rebound adjustment on the shaft and compression (high and low) adjustment on the reservoir.
Equipped with the 50 DA shaft and the FA 3030 Piston, combined they can provide almost any damping curve and adjustment style. User desired characteristics are easy to achieve with our valving matrix. The flow paths in the system are designed to produce significant low speed damping forces with low hysteresis. This is used with our proven damping philosophy in compression to give the moest direct JRZ feeling ever.
The FA 3030 piston allows a large range of dyno curces giving the race engineer the possibility to create specific damping characteristics and fine tuning options. The FA 3030 gives a high response system to be combined with the proven JRZ approuach to create compression forces from shaft displacement. This results in much improced chassis and ride height control while maintaining tire wear and compliance over bumps/kerbs.
Valving on the FA 3030 piston can be chosen to create more or les direct damping at the piston, which will effect the amount of hystresis.