What is the difference between a “Mono tube” gas charged shock and a “Twin Tube shock”?

-Mono tube shock also know as a “Gas shock” is designed and operates with the shock oil under pressure. this pressure is housed in a separate chamber sometimes referred to as a Bulb, or an external revivor .The gas chamber is Divided from the oil of the shock often by a floating piston or a rubber bladder. The chamber is charged with nitrogen. The amount of charge pressure is directly dependent on if that shock has an optional base valve and or what compression value the shock is tuned for. (see base valve and charge pressure explanation below ) The shock body you see from the out side of the shock. Internally , it is the surface that the piston sides on. This single tube body if dented or damaged will not allow the internals of the shock to work correctly and often times cause damage to other components inside.

-Twin Tube shock Commonly known as an “oil shock”. Also has a gas chamber , but it is often a proprietary plastic bag wrapped around a secondary tube inside of the shock. This secondary tubes internal surface is the surface that the piston will ride on. Twin tube shocks require a base vale to operate. The base valve creates a controlled transfer of fluid from the internal chamber, to the area between the outer body and the inner tube. This area is the reservoir to the shock to store oil and the gas bag.

What is the job of the shock ?

In circle track the shock has 2 main jobs:

Traction. If the spring and shock combination is to stuff you risk skating across the track surface or bouncing on top of it, Both situations involve lowering the effectiveness of the tire and its grip to the track surface.

Control the amount of understeer and oversteer (tightness and looseness) present in a chassis at particular parts of the track. Also known as timing. While the springs hold the car up and at attitude. The shocks will hold it or release it from a position on the track how ever long or quick that is needed.

What is “Cavitation”?

Vaporous cavitation is an ebullition process that takes place if the bubbles grow explosively in an unbounded manner as the Air and moisture trapped in the shock oil turn to vapor. This situation occurs when the pressure level goes below the vapor pressure of the liquid. This can be happen when there is Low charge pressure or low oil level in the shock. When cavitation occurs you now have air bubbles and vapor traveling through your valving. This will lower your dampening values and change the characteristic of the cars handling.

What is a base valve ?

A base valve provides enough hydraulic back pressure to force the oil through the piston valving during the compression stroke yet allow enough oil to flow into the twin tube reservoir , or to the gas chamber. Rather than relying alone on gas charge pressure to control the oil flow through the piston valving and cavitation. A twin tube shock will always have need a base valve. a Monotube shock a base vale will be optional. In circle track, higher gas pressure is often misunderstood and looked down upon; a base valve will be used to lower the amount of charging pressure needed, wile increasing the feel of the car to the track surface. A base valve will not always make a gigantic positive improvement to your chassis and handling but it will never hinder you.