shock absorbers 101
•The suspension system controls movements of the chassis when the wheels hit bumps or during natural weight transfer when the chassis is accelerating, decelerating, or negotiating a turn. Shocks and springs work together to control how the chassis moves. The springs absorb the bumps and control body roll. Shocks control the speed of extension and compression of the spring during weight transfer. A stiffer shock will slow down a spring's action; a softer shock will allow the spring to act faster.
•The primary purpose of the shocks and springs is to make the chassis stable and predictable while driving over bumps or ruts. If the shock/spring combination is too stiff, the tire can be pulled off the track surface for a period of time, eliminating that tire's traction ability. If the shock/spring combination is too soft, the chassis can bottom out on the track, again hindering traction ability. This loss of traction in both scenarios can cause the chassis to skate and make the chassis unpredictable and difficult to drive. Also, it can make it impossible for the driver to tell if the chassis is tight or loose.
•The secondary purpose of shocks and springs is to control weight transfer while executing a turn. Once again, springs control how much weight and shocks control how fast. The faster the weight is transferred to the rear, the tighter the car will be under acceleration. The faster the weight transfers to the right rear, the tighter the car is going into the turn. Softer rear and stiffer front springs will transfer more weight to the rear. Stiffer left side and softer right side springs will tighten the chassis in the middle of the turn.
recommended ARS shocks | | DRY/SLICK TRACKS | | | Left Front | | Right Front | | 1060.5/2 | (Twin tube shocks) | 1060.5/2 | | E1065-0.5/2 | (E-series Adjustable Fronts) | E1065-0.5/2 | | | or | | | 3260.5/2 | (Monotube shock) | 3260.5/2 | | E3264-0.5/2 | (E-series Adjustable Fronts) | E3264-0.5/2 |
Left Rear
| |
Right Rear | | 1065/2 | (Twin tube shocks) | 1063 | | B1068-2/2 | (Cockpit Adjustable) | BRC1065-1 | | B10610-3/2 | (Option for tracks with
fast corner speed) | B1068-2/3 | | E1068-2/2 | (Eye Adjustable) | ERC1066-1 | | | or | | | 3265/2 | (Monotube shock) | 3263 | | B3268-2/2 | (Cockpit Adjustable) | BRC3266-2 | | *B32610-5/2 | (Option for tracks with
fast corner speed) | B3266-2/3 | | E3268-2/2 | (Eye Adjustable) | ERC3265-2 | | |
WET TRACKS
| | | Left Front | | Right Front | | 1063/2 | (Twin tube shocks) | 1062 | | E1065-0.5/2 | (E-series Adjustable Fronts) | E1065-0.5/2 | | | or | | | 3263/2 | (Monotube shock) | 3262 | | E3264-0.5/2 | (E-series Adjustable Fronts) | E3264-0.5/2 |
Left Rear
| |
Right Rear | | 1066/2 | (Twin tube shocks) | 1064RT | | B1068-2/2 | (Cockpit Adjustable) | BRC1066-1 | | *B10610-3/2 | (Option for tracks with
fast corner speed) | *B1068-2/3 | | E1068-2/2 | (Eye Adjustable) | ERC1066-1 | | | or | | | 3266/2 | (Monotube shock) | 3264 | | B3266-2/2 | (Cockpit Adjustable) | BRC3266-2 | | *B32610-5/2 | (Option for tracks with
fast corner speed) | B3268-2/3 | | E3266-2/2 | (Eye Adjustable) | ERC3266-2 |
*special order
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shock and bar terminology
“Dampening” or “damping” is a term used in shock technology meaning “to check, depress, reduce or lessen.” These terms can be used interchangeably.
Torsion Bars achieve suspension properties through twisting of one end of the bar while the other end is held firm. Torsion Bars are simply another form of springs and could be referred to as “springs”. “Compression” is when the shock gets shorter; “rebound” is when the shock gets longer. Example, when you step on the front bumper you are compressing the shocks, when you release your foot off, the shocks rebound.
shock absorbers: monotube vs. twin tube
•Monotube shocks are also incorrectly known as gas shocks. Both monotube and twin tube shocks use gas pressure. Monotube shocks use high pressure gas (nitrogen) on the opposite side of a floating piston to keep a constant volume of oil in the shock body as the shaft adds and subtracts volume when the shock oscillates. Twin tube shocks use a lower pressure gas in a bag to achieve the same result. Monotube shocks would be more accurately called high pressure gas shocks.
•Monotube shocks have been around for many years. Their technology has just recently trickled down from Formula 1 racing through NASCAR to dirt track racing. Many engineers feel that monotube shocks have an advantage, since their larger pistons displace more oil for a given stroke. This is
especially true for the rebound stroke. The greater the amount of oil moving through a shock’s piston, the easier it becomes to regulate the flow and thus control the dampening forces of the shock. Although fading is generally not a problem for micro sprints, monotube shocks also will not fade due to heat. They stay cooler because the piston and oil are in direct contact with the outside wall of the cylinder allowing for better dissipation of heat. Monotube shocks also last longer because they have less moving parts to wear out.
•Twin tube shocks use a rupture-prone gas bag to hold the nitrogen. When this bag breaks the nitrogen mixes with the oil making the shock skip as the gas moves through the piston orifices. Bubbling noise can be heard when the shock is actuated by hand. In contrast, twin tube shocks can sometimes be advantageous: twin tube shocks can still function properly with small dents in the housing because of the use of their inner cylinder.
•Rod pressure is the amount of force that pushes the shaft of the shock out. Rod pressure is undesirable because it essentially increases spring rate. This makes the car feel like it is on top of the race track. Another advantage of Twin tube shocks is that they have less rod pressure due to the smaller piston and the lower gas pressure.
•So whether you choose the high performance monotube or the economical twin tube shock, remember that it is much more important to select the correctly valved shock for your car.  |
setting gas pressures
The pressure in the ARS monotube shocks can be adjusted from 10 psi to 100 psi. To start set the front shocks at 40 psi and the rear shocks at 20 psi. The VRP shocks can be adjusted from 35 psi to 150 psi. To start set all shocks at 65 psi. - Back the wing nut off all the way on the inflation unit before screwing it on the Schrader valve of the shock.
- Tighten the hex nut coupler onto the valve of the shock.
- Screw the wing nut all the way clockwise so it opens up the shock valve.
- Pressurize the shock to the desired pressure using nitrogen gas only.
- Screw the wing nut counter clockwise all the way to seal the shock valve.
- Gas pressure can be heard escaping from the shock as the inflation unit is removed.
- 5 to 7 psi will be lost every time the inflation unit is applied to the shock.
gas pressures
The nitrogen gas pressure in a monotube shock is required at all times for it to function properly. The gas pressure can be adjusted to accommodate various track conditions. More pressure is needed for rougher track conditions, less for smooth track conditions. Less pressure in the rear shocks allows more weight transfer to the back for more forward bite (tighten up the car), more pressure in the rear shocks allows less forward bite (loosen up the car). Increasing the pressure in the front shocks will provide more weight transfer to the rear providing more forward bite, less pressure in the front
will provide less forward bite. shock dynomometry
Stop guessing and start knowing exactly what your shocks are doing. A run
on the shock dyno can:
* Detect malfunctioning shock(s)
* Identify problems with chassis handling
* Plot rebound and compression dampening curves
* Compare your shock to the manufacturer’s specifications
* Find out if your shock is on the stiff side or the soft side of the manufacturer's tolerances |
ARS BRC3266-1
remote adjustable shock for right rear |
VRP Right Front-
threaded body (left) and smooth body shocks |  |  |
Mike Dicely is the President of Hyper Racing, located in Lewisberry, PA. Visit www.hyperracing.com for more information about shock technology and the state-of-the-art Roehrig Shock Dynomometer at the Hyper Racing Shop.
Text and images are the property of Hyper Racing and cannot be used with-
out permission. |
