Component: 2011 Avalanche Chubie Rear Shock with independent hi/lo compression damping adjuster
Intended Use: Any and everything on the dirt
Size Tested: 8.5” (eye-to-eye length) x 2.5” (stroke) [216 x 63mm]
Shock weight (w/ 450lb spring): 930g. Shock body: 510g
Bike: 2010 Santa Cruz Nomad Mk II Aluminum Frame
Bike/Shock Weight: 32 lbs.
Rider: 5’8”, 165lbs. I prefer to jump over or around obstacles instead of plowing through them.
Test Locations: New Hampshire, Vermont, Utah, Colorado, British Columbia
Days Ridden: ~220 Days
Avalanche suspension sells shocks that are custom valved for the rider. Their products are designed to provide optimal suspension performance for individual users, instead of the average user. Their products break into two categories: (1) complete forks and rear shocks, and (2) replacement cartridges and shock rebuilds for common forks and shocks.
The Avalanche Chubie is one of four different rear suspension options manufactured by Avalanche. The Woodie, Chubie, and DHS are all comparable shocks, while the Montie is a less expensive option that does not feature externally adjustable high and low speed compression adjustments.
The reason for offering three seemingly similar shocks is to solve the fitment and performance problems that different suspension designs present. All three of the shocks share common components inside their main bodies, but feature different external reservoirs. So let’s talk reservoirs for a minute.
Avalanche has two different reservoir designs for their three reservoir-equipped shocks; the Woodie and DHS share a rubber bladder reservoir design, while the Chubie uses a floating piston.
External reservoirs are used to improve performance by offering a greater oil volume being pushed through more complex valving and providing more liquid mass to absorb heat and delay fading.
As a shock is compressed, the oil volume available in the main body of the shock is displaced by the shock shaft. That oil is pushed into the reservoir, compressing the gas there. In order to prevent foaming and cavitation caused by gas mixing with oil, the two are kept separate in the reservoir by either the floating piston or the flexible rubber bladder.
The bladder design (used on the Avalanche Woodie and DHS) has the best small bump compliance, since it has no seal stiction to overcome. This sensitivity makes it a great choice for riders that prioritize traction and initial stroke suppleness.
The floating piston of the Chubie enables the shock to be easily tuned for pedaling and end-stroke performance by making internal changes to the nitrogen pressure.
Speed Sensitive Damping
Avalanche uses speed sensitive damping (SSD) in all of their shocks. The “speed” being referred to here is the speed of the damping piston or shaft travelling in the oil, as opposed to the speed of the rider. The degree of damping is dependent on the shaft speed only, not its position in the damper at any given time.
This is in contrast to one of the common alternatives, position sensitive damping. In a shock featuring position sensitive damping, the compression damping force increases throughout the stroke of the shock—the damping is dependent on the position of the shaft in the stock, and independent of the speed of the shaft.
While position sensitive damping is great for making a shock resistant to bottoming, it can limit the shock’s effectiveness when the shock is already compressed halfway from small trail features and the rider hits a large rock or root in the trail—the damping force will be too great to allow the shock to reacte sufficiently.
With speed sensitive damping, that larger impact is absorbed in a controlled manner because it creates a high shaft speed and a corresponding response from the high speed compression damping (more on that below).
Position sensitive damping is usually used because of its simplicity, which makes it less expensive to design and manufacture. Speed sensitive damping circuits are typically more complex, and thus more expensive.