The next step in the setup of your Topaz Air shock is understanding the bladder. We have implicated the use of a bladder in all of our rear shocks for increased performance in many aspects. Bladders have been widely used in motocross shocks for years but haven’t been seen too often in mtb shocks. Why is that? Bladders can be costly on the production side and take skilled technicians to properly bleed and install. On mass-produced suspension products that isn’t something they’re willing to invest in. At DVO we take pride in making high performance products and cutting corners in production at the cost of performance isn’t what we’re about.
WHY USE A BLADDER?
Bladders are located in the reservoir of the rear shock and take the place of a traditional IFP or internal floating piston. They both have the same purpose but completely different ways of executing it. That purpose is to seperate the air from the oil. A bladder is basically a ballon which is filled with air and seated to the end cap. The bladder is filled with a high PSI to push back against the oil which creates pressure in the system. As the shock is compressed, oil flows through the the system and starts to compress the bladder.
When the shock goes to extend again, the bladder pushes the oil back in the opposite direction. This decreases the chances of what’s called cavitation. Cavitation is when there is a gap in the oil caused from air bubbles and creates a temporary loss of damping. Here’s an example of cavitation. Picture turning on a hose, what happens as the water is pushing the air out of the line? Water intermittently shoots out in between gaps of air. This same situation happens in suspension causing a loss of damping.
The real benefit of using a bladder over an IFP is when the shock is working dynamically or in “riding situations”. As the shock is compressing and rebounding at a high velocity, it can sometimes have a difficult time changing directions. An IFP usually has a moment of hesitation in that situation due to stiction between the outer O-ring and the inside surface of the reservoir. With a bladder that can’t happen and you get unmatched small bump sensitivity with a seamless transition from compression to rebound.
CAN I ADJUST THE PRESSURE OF THE BLADDER ON MY SHOCK?
Absolutely. Changing the bladder pressure is easy and something you should check consistently. Just unscrew the air cap at the end of the reservoir and use a shock pump to adjust or check the pressure. When checking the pressure, the initial reading from the pump will be low. This is because air needs to fill the hose of the pump before the PSI can be determined.
HOW WILL THE PRESSURE AFFECT THE PERFORMANCE?
The pressure within the bladder will have a drastic affect on performance. As we talked about before, the higher the pressure the less chance you have of cavitation. The pressure range of the bladder is 170-200PSI. The bladder pressure also has an effect on the entire stroke of the shock. The higher the bladder pressure the firmer the shock will be. The lower the pressure, the softer. Lighter riders can run a lower bladder pressure and heavier riders should ride a higher pressure.