With all of the different types of shocks on the market and every style with a pro and con, how’s a person to choose which style to buy? The easiest way to determine which style is right for you is to do a general break down with the features and benefits of each style. But first, a little background information about the shock itself.
A shock absorber is a mechanical device designed to smooth out or dampen shock impulse, and dissipate kinetic energy. Shocks dissipate this energy in the form of heat, thus heat control is a primary concern in shock design.
Most shocks use a combination of gas (most commonly nitrogen) and oil separated by a valve to provide their dampening effect. While the gas does provide some positive pressure against the oil affecting the firmness of the shock, its primary purpose is to raise the oil’s boiling point so the heat can be dissipated before it begins to cavitate.
Cavitation happens when the oil becomes so hot and thin that it starts to leak through the valve and mix with the gas. This causes aeration in the oil and makes the shock ineffective. Often this phenomenon is referred to as shock fade. The result is limited damping of the suspension and very poor vehicle control. Excessive heating (as a result of overwork) should be avoided as it accelerates wear dramatically shortening the life of the shock considerably.
Remote Canisters are the hottest style on the market but they are also the most expensive and require the most maintenance. So, why are these shocks selling like hotcakes? Actually, because they’re cool – in temperature, that is – and also because the shocks can be adjusted to the owners ride preference. As mentioned earlier, heat, which causes shock fade is the worst thing for a shock and a remote canister helps prevent excessive heat by putting the gas into a separate canister from the oil filled shock. This complete separation of gas and oil allows for a greater oil volume in the shock housing to dissipate additional heat and less opportunity for cavitations. That’s the good news…
The bad news is that unless you are part of a skilled racing team or are a suspension engineer, you are likely not all that qualified to adjust your adjustable shocks leaving you with substandard ride quality that could adversely affect the vehicle handling and control. There is another dirty little secret about these shocks that you may not be aware of, and that is that the remote canister that holds the gas uses a Schrader valve like your bicycle tire and Schrader valves bleed off over time. So, these shocks need to be recharged and readjusted frequently – as often as every 5-10,000 miles. If you happen to have unlimited resources to compressed Nitrogen this may not be a problem, but for most people, it’s rather hard to come by. And, unreliable shops have been known to charge the canisters with compressed air instead of Nitrogen. This is very bad for a couple of reasons, first, Oxygen is not an inert gas like Nitrogen and second, air contains water and water will rust your shock from the inside out.
Bottom line, ARB only recommends their Old Man Emu brand Remote Canister Shocks for people who are racing because, generally, only people who are truly racing can induce enough heat in their shocks to benefit from this type of shock and tolerate the increased maintenance procedures involved. Basically the cost to benefit ratio simply does not makes sense for the average off-roader.
Unlike the remote canisters, mono tubes carry the oil and gas within the shock housing separated by a valve. This style of shock is called a mono tube because the piston rod assembly runs in a single wall tube. This design has cooling advantages over typical dual tubes as the area producing the heat (piston/shaft assembly) is nearly in direct contact with passing airflow, but is very susceptible to damage from rocks and other road debris as any impact with the shock tubing will render the shock unusable.
Beyond the structural design, there are differences in the performance aspects typically associated with this type of shock when compared with others. Generally monotube shocks use higher gas pressures than dual tube shocks. This has the advantage of making the shock extremely responsive to road conditions, but can easily move towards the harsh end of the ride spectrum if not tuned perfectly to the vehicle they are fitted too. This harshness will typically be most noted at low driving speeds on rough roads.
OME Nitrocharger shocks are a traditional twin tube design. They use a heavy steel outer tube over the more fragile inner piston tube. This has several advantages over a mono tube design. The outer tube allows for dents and dings without altering or affecting the shock operation at all. It also creates a chamber for gas and oil to expand allowing for a greater volume of both. This gives the shock a good combination of heat capacity (what it can absorb prior to fade) and surface area to dissipate heat into passing airflow. They are a low pressure gas shock that has very soft ride characteristics are low speeds with resistance building rapidly (for vehicle control) during higher speed cycles.
Where the OME Nitrocharger differs from the average shock is in the size of the internal components used and the engineering development behind the valving. The piston shafts are constructed of 18mm diameter chromoly steel using a huge 35mm banded piston, high quality oils and other extreme duty parts for a robust, tough shock. Tuning is load and vehicle specific. Our engineers tune the shock to the particular needs of a vehicle, from stock trucks to heavily loaded expedition trucks. As a result OME often has several available part numbers for a single vehicle application allowing the consumer to choose the shock that best meets their specific needs.
Old Man Emu Sport Shocks: Twin Tube with a monotube attitude.
The OME Sport line was developed to give our engineers more options. It’s essentially a hybrid between a traditional twintube structure and monotube ride control. These shocks give us the best of both worlds and allow our engineers to tune the shocks over a much greater range for enhanced ride and handling characteristics. The OME Sport line uses much of the same construction as the Nitrocharger shock with a twin tube body, an additional set of valves were added at the base of the piston rod to greatly enhance low speed control. The result is excellent responsive handling with good ride quality and tremendous durability in an off highway environment.