It's fair to say that the average 4WD takes far more punishment than most other road vehicles, and one part of a 4WD that is most susceptible to wear and tear while off-roading is its shock absorbers. As such, many 4WD owners choose to have their vehicle's stock shocks replaced with nitrogen gas shock absorbers, and these heavy duty pieces of equipment can provide many advantages to the dedicated offroad driver. However, replacing your shock absorbers in this manner also comes with a few inherent disadvantages, so you should fully take stock of your needs before deciding whether or not to invest in them.
What are the advantages of installing nitrogen shocks?
- Eliminates aeration problems: Nitrogen shock absorbers are essentially similar to regular hydraulic shocks in form and function — however, unlike regular hydraulic shocks, they do not suffer from problems with aeration. This dangerous phenomenon occurs when air leaks into a hydraulic shock absorber's internal fluid and can dramatically undermine its ability to absorb shocks. However, because nitrogen shocks are filled with highly pressurised nitrogen, any leaks that do occur eject nitrogen rather than take in air, giving you safe and reliable shock absorption even with a damaged shock.
- Faster rebound: Because the nitrogen in a nitrogen shock is so highly pressurised, it also forces the shock to return to its resting state more quickly than other types of shock. As such, a 4WD with nitrogen shocks will return to an even keel when traversing uneven ground far more quickly, giving you more control and vastly increasing your ride comfort.
- Counteracts brake dive: This highly pressurised nitrogen also helps to counteract the phenomenon known as 'brake dive', which occurs when heavier vehicles (such as your average 4WD) brake quickly and the nose of the vehicle dips severely as a result. Faster rebound times bring your nose back to a level position more quickly, preventing excessive lurching during hard braking maneuvers and minimising the chances of your 4WD's nose taking damage.
What about the disadvantages of installing nitrogen shocks?
- Price: It goes without saying that nitrogen shocks are generally much expensive than conventional hydraulic or stock shocks, but can also be more expensive than other types of high performance shock, such as foam cell shocks.
- Leaking over time: Even the toughest and most infrequently used nitrogen shock will lose internal pressure over time and an aged nitrogen shock will need to be refilled professionally before it can be used safely.
- Overheating issues: Nitrogen gas is not a particularly good conductor of heat, and nitrogen shocks that receive particularly heavy use over long periods can overheat, reducing their service life and increasing chances of mechanical failure.