The 12.31 has a 22 [mm] strut shaft.
The 12.32 has a larger strut shaft.
The 12.33 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.
Improve your McPherson damper by upgrading to our UPSIDE DOWN McPherson struts. This is our strongest and stiffest strut construction.
The upside down McPherson strut applications are being used when extreme conditions are being expected. These conditions can occur for example during Rally racing. The upside down struts are designed to work with very high side loads and peak forces which are seen when the car makes jumps.
Control of the unsprung mass is achieved with our blow off valve. Steering balance and weight transfer rates are tuned with the low speed adjustment. The high speed compression adjustment sets the blow off velocity of the damper, allowing for harshness to be separated from control. Blow off damping settles the car on bumps, curbs, and maximizes grip. Low speed sets the speed at which the blow off valve opens allowing for fine tuning of balance and adjusting for surface conditions.
Above is the high speed compression adjustment range of a typical JRZ 12 series. The blow off system, innovated by JRZ, is seen moving the opening point of the valve up and down. The full range is useable and each step is a fine yet noticeable increment.
Above is the low speed compression adjustment range of a tpical JRZ 12 series. The low speed adjustment, innovated by JRZ, is seen by the changing angle of the force line. The low speed adjustment is usable at every high speed click.
Sprung mass is controlled with rebound damping, delivered smoothly by the 8060 motorsport piston. The 12 series rebound system and 8060 piston provides a linear damping characteristic with smooth pressure development independent of compression forces. This allows the damper to transition between rebound and compression efficiently, maximizing grip and reducing tire wear.
Above is a graph of the rebound adjustment range of a typical JRZ 12 series. It can be seen that the steps are even, the range is large and the curve is smooth. This allows the chassis to be tuned predictably, step by step.
Control is achieved by using compression damping controlling the movement of the unsprung mass. By doing this the car will take kerb stones or road bumps extremely well and the car will not be unsettled with great control for the driver.
Using compression damping to control the unsprung mass will result in less tyre wear and better tyre temps. The unsprung mass will move according the tyre’s natural frequency. Using the compression damping the contact patch of the tyre to the road will be maximized.
Damping is available over a large adjustment range with fine tuning increments. Set up is easy to find and spring rates can be changed without having to revalve the damper.
The combination of the 22 mm shaft and the use of nitrogen pressure results in a lifting force created by the damper. This lifting force is available through the whole stroke of the damper and works together with the spring, The lifting force is not a springrate, but gives the car platform.