WHICH SHOCK IS RIGHT FOR ME?

There are basically three shock types available from most of the shock manufacturers: emulsion type, internal floating piston type, and reservoir type.

EMULSION SHOCKS:

Emulsion means the nitrogen gas and shock oil are allowed to mingle. There are a few reasons why emulsion designs are common. First, they cost less to build so they generally have a more attractive retail price. Secondly, in very short shock builds there may be no room for a separation piston without significantly reducing stroke so it is built as an emulsion instead. Thirdly, in some applications such as the front shock on a BMW Telelever equipped street bike, the leverage ratio is lower and the spring rate and damping forces are light. Moving the mass of a separation piston in an IFP design requires some energy and this can make the shock less responsive. Plus, with the low spring rates on these front Telelever emulsion shocks, overheating and cavitation is typically not a concern.

The emulsion design can be problematic however when used as a rear shock if shock temperatures climb from riding on roughs roads/dirt roads for extended periods. The oil cannot dissipate the heat to the cylinder wall as effectively when it has gas molecules in it, and the vapor pressure drops as the oil temperature rises. Under these conditions the oil cavitates which means you're pushing foamy oil through the valving which leads to damping fade. If the shock gets hot enough, seal failure can occur.

In conclusion, emulsion shocks work fine on street bikes where high shock temperatures are generally not an issue. They are not recommended for adventure bikes however which might be ridden off road or where riding on rough asphalt or dirt roads for extended periods is common.

Emulsion Example - Front

Emulsion Example - Rear

 
IFP SHOCKS (Internal Floating Piston):

IFP shocks are the next step up. An additional piston is added to the assembly to keep the oil and gas separate. Because the oil is just oil and with no gas molecules in it, the oil can shed the heat to the cylinder wall better which gives better thermal stability. These shocks are usually produced with a 6082 heat treated aluminum cylinder which sheds the heat better than the steel cylinders commonly used with emulsion shocks.

IFP Example - Front  

IFP Example - Rear


RESERVOIR SHOCKS:

Reservoir shocks are at the top of the list in terms of adjustability, performance and heat management. By adding a reservoir, the nitrogen is no longer inside the shock, it is contained in the reservoir. This means that instead of the shock being only half full of oil as is the case with emulsion and IFP designs, the shock is now 100% full of oil.

With this additional oil capacity and the increased surface area of the shock created by the added reservoir, overheating is rare regardless of terrain. In addition, a reservoir shock typically has a more advanced compression circuit.

In the case of the common Dutch high/low speed design, the compression stroke is valved based on the velocity of the oil. Low speeds of compression are handled by the low speed path which has an adjuster, high speeds of compression are handled with an additional circuit that opens when there is high velocity demand, and it also has an adjuster.

These reservoir shocks are ideal for adventure bikes which are ridden off road, and will give any rider best ride quality over the roughest roads. Reservoir shocks also give you ultimate adjustability due to the three damping adjusters (rebound, high and low speed compression) provided. Even if you never touch the compression adjusters, the more advanced design will do a better job of smoothing out the biggest bumps.

Reservoir Example - Rear

IN CONCLUSION:

If all the shocks were all the same price, we would only sell reservoir shocks because they are superior to the other designs. But they are not all the same price and frankly not every rider needs a reservoir shock. You would have to look at your budget and your needs.

Most of our street bike customers are delighted with the improvements that they enjoy from upgrading to something like the Wilbers emulsion shocks; model 630 front and 640 rear, or the TFX IFP shocks model 130 front and 140 rear.

Most will add the hydraulic preload adjuster to the rear shock which is similar to how the stock shock is outfitted. This makes it easy to adjust sag when your loads change. If your loads don't ever change, you could omit the HPA and save your pennies by buying the rear shock with just the threaded preload ring adjuster.

You can also replace one shock at a time which helps some customers with budgeting. The rear shock is the first place to start.

Due to the fact that we carry so many brands, we offer unbiased recommendations based on your budget and riding conditions.

We are available by phone for a more in depth discussion of your shock options at: (831) 438-1100.