i am setting my z28 up to start bracket racing and am looking at the difference in front struts and rear shocks. what is the difference between 90/10, 70/30, & 50/50? What do the numbers stand for? any help is welcome.

 

The numbers relate to the directional dampening, or resistance to movement, of the shock/strut.

A typical shock is 50/50, where the dampening is the same in each direction (extension & compression). The dampening on a typical front drag only shock is 90/10 to allow the front to rise quickly on launch and transfer weight to the rear wheels.

Of course, you may not want that to happen at every traffic light on a car driven on the street. Valving internal to the shock/strut controls the dampening.

Some manufacturers offer adjustable shocks/struts to allowing you to tune the action for your needs. Some can even be adjusted w/o removing the shock/strut.

Hope this helps.


Remember: Keep the shiny side up!

 

thanks for the info that makes sense. if a good drag shock for the front is a 90/10 what would be good for the rear.

 

50/50 is typically used for the rear.

The front is where the different valving usually comes into play. In general:

Front Rear
Street/stock: 50/50 50/50
Street/Strip: 70/30 50/50
Strip: 90/10 50/50

Of course, there are always exceptions.

Keep in mind the primary purpose of a shock/strut is to keep suspension travel under control and tires in contact w/ the pavement.

If the spring & shock/strut combination is too stiff, cornering might be great, but the ride will be harsh, the rest of the suspension will take a beating, and the tire may leave the pavement on bumps. If the combination is too soft, handling will suffer and, on a bumpy road, the tire may spend more time off the pavement than on. Not a good situation.

 

thank you