Developments in Shocks

Understanding shocks and chassis tuning with shocks has become a very important setup tool in modern short track racing. Before you even install the shocks on your Late Model or Street Stock, you must first choose the brand and the type of shocks that are best for you.

Obviously, the rules of each division will limit the choices of shocks. Some tracks have placed limits on the sale price of the piece while others have limited the number of adjustments (such as external rebound adjustments) a shock can have.

Aside from the rules, another choice for selecting shocks has developed only a few years ago as a new generation of shocks began to be produced. These are the user-rebuildable shocks. Up until that point, all of the shocks available had been of the sealed variety.

It is rather easy to tell the difference between the shocks. The user-rebuildable shock has a wrench surface on the threaded bearing end on one side of the main body. The nonuser-rebuildable type shocks are welded or require a special tool to remove the end bearing. These shocks are either non-serviceable or need to go back to the factory for rebuilding.

Penske Racing Shocks offers a short track shock, the 7100 series for a steel non-coilover and a 7500 series for an aluminum coilover. Penske shocks achieve their damping with fluid being forced through a series of spring steel washers. Changing the thickness of these washers produces different valvings. The racers themselves can change the valving at the track! It makes Penske shocks both rebuildable and revalvable. Not only can the racers change the oil themselves, but they can change the valving stack to achieve a different value. To illustrate how easy it is, both the compression and rebound damping can be changed in less than 10 minutes with no special tools (except an inflation valve to pressurize the shock with nitrogen).

Another feature that makes these products unique is that since they are rebuildable by the user, they can also be repaired by the user. If you bend the shaft on a Penske shock, you can fix it for about $40. With some sealed shock companies, you would have to buy another new shock. Penske sells complete replacement parts for the entire shock.

In their research and development, Penske engineers found shock consistency to be a problem in two separate areas. First, shocks would not stay consistent after extended usage (over 30 to 40 hours of race time). The oil inside the shocks tended to break down and thus lose its viscous properties. After finding this out, Penske engineers started investigating different oils for use in the shocks. They also investigated oil change intervals to keep the shocks as consistent as possible. The end result points to changing the shock oil after 30 hours of use, which translates into about a third to a half of a short track racer's season.

Penske officials believe a set of shocks, with proper maintenance and rebuilds, will last a racer five years or more. Shocks can also be sent back to Penske for rebuilding and revalving, for a small fee.

A relatively new player in the shock market came about from work done by Winston Cup driver Derrike Cope. CV Products has introduced their new 2-Qwik racing shock that is a rebuildable shock with some very unique features. The 2-Qwik shock is built on four basic concepts--simplicity, performance, adjustability, and repeatability. The 2-Qwik shock allows a racer to purchase one set of shocks and tune to almost any racetrack or situation. It may appear the 2-Qwik shock is no different from others, but there is one more interesting feature. These shocks require no pressurizing process. Due to their unique design, these shocks are self-pressurizing. Consequently, anyone can revalve and adjust their shocks in minutes.

The shock body is built from fully CNC-machined billet aluminum. All shafts are high quality steel with a premium hard chrome finish. Pistons feature a solid wear band for lower friction and longer service life. Depending upon the racing application, linear or digressive pistons and shaft options are available.

CV Products' Mike Gross has been involved in researching this shock design to bring it to where it is today. By listening to racers and shock specialists, the company has worked to make a very versatile yet easy-to-use shock for many divisions in racing. The 2-Qwik shock follows the same "larger shims require more force" valving philosophy. These shocks are approved for Winston Racing Series competition and CV has begun seeking Winston Cup, Busch, and Truck Series approval. The lighter weight of the unit is another attractive feature. With fewer parts and the lightweight design, the shock package can result in a savings of up to 15 pounds in some cases.

CV also states these shocks, with proper maintenance and rebuilds, will last a racer five years or more. CV also offers a service to rebuild a racer's shock for a small charge.

AFCO began their shock division to complement a very successful line of springs and chassis components. The decision to make this jump has been very beneficial to AFCO. They have more varieties of short track shocks in their line than most companies. They offer both sealed and rebuildable shocks.

Their sealed shock line consists of three basic types. The entry level is the street-type shocks with passenger car ends on them. Next is the fixed bearing shock with bearing ends. And the top of the sealed line at AFCO is the 10 series with upgraded bearing ends.

Bill Workman of AFCO, who is an active dirt Late Model racer, admits the sealed shocks are less expensive to get into, but have a limited lifetime because they cannot be rebuilt. Workman feels sealed shocks have a main use in budget classes or in series that experience high levels of front suspension damage, such as open wheel Modifieds.

"The advantage to rebuildable shocks is that you only have to buy them once," says Workman. The rebuildable shock line takes over where the sealed line leaves off. The entry level rebuildable is a smooth steel-body shock. There is also an aluminum coilover version. The top of the rebuildable line is a double adjustable shock. The AFCO shocks are not owner rebuildable or revalveable. The racer can send the shock back to AFCO and have the company rebuild or revalve the shock. This service includes a dyno test on each shock. AFCO will not return a shock to the racer unless it meets the "like-new" standards.

The gas in the shocks is contained in a bladder to prevent the mixture of the gas and the shock oil, which is different from shocks where the oil is stored in a separate chamber or stored in the oil chamber. Workman also stressed that shock mounting is critical to any manufacturer's product. If a tire were to rub against a shock even for just a short duration, the intense heat generated would cause extreme damage.

Another major player in the short track shock field is Pro Shocks. They have been associated with hundreds of champions since coming into operation in 1983. Pro Shocks prides itself on the quality of its product and the performance it can deliver.

A popular choice of shocks among racers is Pro's Rebound Adjustable shock that was introduced a few seasons ago. This shock served as a time-saving tuning device because it eliminated the need for shock changes in cases where a rebound change became necessary. These lightweight aluminum bodied shocks are made of 6061 T6 aluminum. Yet another innovation in the shock field came with the introduction of the SS Series for Street Stocks. These shocks adjust to positions of stiff rebound, soft rebound, or 50/50 (rebound versus compression).

Pro Shocks offers a skilled tech service staff who make certain the new parts and repaired customer parts meet exacting standards before shipping. Feeling that the customer couldn't reach the same level without the benefit of high tech equipment like a shock dyno, the company does not offer user rebuildable shocks as part of its line of products.

Your choice of manufacturer for short track shocks will require you to ask a lot of questions. Cost, life, and options should all be considered. In addition, the number of different tracks and shock tuning choices should all factor into the final purchase. Shocks for racing programs should be looked at as an investment. The initial cost may be quite high, but the years of usage you will get out of a quality shock will certainly pay off.