We cannot use a true 50/50 rated shock (where the resistance is the same on both rebound and compression), when installed in combination with a spring. Correct thinking would have us install a shock that has more rebound control than compression resistance. More and more teams are utilizing split-valve shocks which are higher in rebound resistance and the results are faster turn speeds due to a more balanced movement of the front and rear suspension systems.
Maintenance Shock maintenance is a must in racing. The shocks do a lot of work throughout each race and certainly through an entire season. We need to be sure to check our shocks for bent components, sticking mono-balls in the ends, leaking fluids and loss of pressure in the pressurized types of shocks. We should find a shock maintenance facility and have the shocks run through a dyno to make sure they hold their intended rate.
If your shocks are re-buildable, take them apart often to check seals, valve disks, and to replace the oil periodically. Always use nitrogen gas to pressurize your shocks and recheck the pressures often. Make sure the gas bag is intact and holds the gas without leaking. Check for contact between the shock body and the coilover spring or any other part of the chassis. This will have a very negative affect on the setup of the car.
In part two, we will get a little deeper into shock technology and design. We will look at modern day shock graphs, and see how we might improve our performance by using different rate shocks in relation to various types of setups, racetrack designs and track conditions.
 A Digressive-designed shock...  A Digressive-designed shock has a considerable amount of low speed control and builds resistance as the shaft speed increases to a predetermined point where the rate digresses and stays nearly the same as the speed increases. This type of design has good low speed control and does not build ultra-high resistance with the high speeds associated with bumps and holes, as in the case of some rough dirt tracks. |  Shock clearance is an issue...  Shock clearance is an issue with some cars. On stock clip front ends, a portion of the spring bucket must be cut away to make room for the shock. The upper control arm must also be clear in the full range of motion that the wheel will travel on the track as well as in the pits. |  A Linear-design shock has...  A Linear-design shock has a piston that is designed to start out with low resistance and continue to build as the speed of the shaft movement increases in a linear fashion. This type of shock has very little low speed control, but very much high speed control. |