AMSOIL SHOCK THERAPY® #5 LIGHT SUSPENSION FLUID

AMSOIL Shock Therapy #5 Light Suspension Fluid delivers fade-free damping and predictable rebounds for forks and shocks on motorcycles, dirt bikes, snowmobiles, ATVs, UTVs, and circle-track race cars. Built on high-quality synthetic base oils, it maintains consistent suspension feel across a wide temperature range where conventional shock oils fall flat.

Suspension fluid does one critical job: control the rate at which your shock compresses and rebounds. When that fluid thins out from heat generated during aggressive riding, desert trail runs, or extended laps on a circle track, damping becomes soft and unpredictable. You lose the precise feedback your suspension was tuned to provide. Cold temperatures create the opposite problem, thickening the fluid and making the suspension feel harsh and unresponsive. Either way, you're fighting the bike or vehicle instead of riding it.

HIGH VISCOSITY INDEX PREVENTS FADE
Heat is the enemy of consistent suspension performance. As shock oil temperature climbs during hard use, conventional fluids lose viscosity and damping weakens. AMSOIL Shock Therapy #5 Light is formulated with synthetic base oils that carry a viscosity index of 209 (ASTM D2270), meaning the fluid resists thinning at elevated temperatures far more effectively than lower-VI alternatives. At 100°C, the fluid maintains a kinematic viscosity of 4.4 cSt (ASTM D445), while at 40°C it measures 12.9 cSt. That spread reflects a fluid engineered to stay in its working range from cold morning starts to sustained high-heat conditions. The pour point of -53°C (-63°F) per ASTM D97 also means it flows freely in winter riding and cold-climate snowmobile applications.

ANTI-FOAM AGENTS PROMOTE PREDICTABLE SUSPENSION FEEL
Aeration is a real problem in high-speed suspension cycling. When air gets whipped into the fluid, it becomes compressible, and compressible fluid means inconsistent damping. You feel it as a vague, spongy response mid-stroke. AMSOIL Shock Therapy #5 Light contains anti-foam agents tested per ASTM D892, with foam tendency/stability results of 50/0 (Sequence I), 40/0 (Sequence II), and 50/0 (Sequence III). Zero foam stability across all three sequences means any foam that does form collapses rapidly, keeping the fluid column solid and the damping response sharp.

REDUCES FRICTION AND PROTECTS INTERNAL COMPONENTS
Every stroke of a shock or fork generates friction between the piston, seals, and cylinder walls. That friction robs energy from the suspension system and creates wear on internal surfaces over time. AMSOIL Shock Therapy #5 Light is formulated with friction modifiers that reduce energy loss for more efficient suspension response, along with anti-wear agents that protect shock internals from premature degradation. Four-ball wear testing (ASTM D4172) at 40 kgf, 75°C, 1200 rpm for 1 hour produced a scar diameter of just 0.44 mm, confirming strong wear protection under load.

SEAL CONDITIONERS EXTEND SERVICE LIFE
Dried-out or hardened seals lead to fluid leaks, contamination, and costly rebuilds. Shock Therapy #5 Light includes seal conditioners that help keep O-rings and seals pliable, reducing the likelihood of premature failure and extending time between service intervals.

COMPATIBILITY AND APPLICATIONS
AMSOIL Shock Therapy #5 Light is recommended for suspension systems where less damping and quicker rebounds are desired. It is compatible with forks and shocks made by Bilstein, Custom Axis, Kayaba, Penske, Race Tech, Ryde FX, Showa, and WP. The #5 Light weight is also recommended for winter use where cold-temperature flow is a priority. For applications calling for Afnor E 48-603, BF Goodrich 0152 (except PM 500 Series), Denison HF-0/HF-1/HF-2, DIN 51524 Part 2, Ford M6C-32, Lee Norse 100-1, or Racine Variable Vane Pump specifications, Shock Therapy #5 Light is a direct fit. To cross-reference against your current shock oil or fork oil product, visit the AMSOIL shock fluid cross-reference tool at AMSOIL.com.