Suspension Fluid

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Controls Friction

Controls friction, heat, wear, foaming and scuffing in suspension components. High viscosity index and shear-stability controls shock fade and inconsistent dampening in temperature extremes.

Formulated for fade-free dampening and smooth rebounds in high-performance applications

AMSOIL Shock Therapy Suspension Fluid is formulated with shear-stable synthetic base stocks with high viscosity indices. Its complete additive package reduces foaming, aeration and wear, while seal conditioners are added to keep seals soft and pliable. AMSOIL Shock Therapy Suspension Fluid has been tested and proven to be a superior, balanced product recommended for a wide range of temperatures and applications.

Controlled Dampening and Rebound

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AMSOIL Shock Therapy Suspension Fluid is formulated to make suspension systems more predictable. Its base oils have inherently high viscosity indices that effectively maintain viscosity, while its anti-foam agents reduce aeration and foam.

Reduces Friction and Wear

The constant friction within a shock body decreases suspension performance. AMSOIL Shock Therapy Suspension Fluid contains friction modifiers to reduce the energy loss caused by friction, while anti-wear agents are added to protect shocks and forks from premature wear.

  • STL #5 Replaces These Lubricants
  • Spectro SPL Ultra Light
  • Ohlins Front Fork #5
  • Race Tech Light
  • Klotz 5W
  • Maxima Shock Fluid
  • RydeFX
  • Silkolene Pro RSF
  • Golden Spectro Very Light
  • Belray Fork 5W
  • Bilstein Bilmst 3030
  • Redline Light
  • SLP Light
  • PJ1 Fork Oil
  • Showa SS05
  • Belray HVI 5W
  • STM #10 Replaces These Lubricants
  • Spectro SK400 Shock & Fork Oil
  • Race Tech Medium
  • Maxima Fork Oil 10
  • Belray HVI 10W
  • Ohlins Front Fork Fluid #15
  • Belray Fork 10W
  • Spectro Fork Oil 10W
  • Klotz 10W
  • Redline Medium
  • Spectro SPL Very Light
  • Harley Davidson Fork Oil Type B
  • Fox Racing Oil
  • Harley Davidson Fork Oil Type E

AMSOIL STL #5 & STM #10 Is Recommended For Applications Specifying The Following:

  • Denison* HF-0, HF-1, HF-2
  • Racine* Variable Vane Pump
  • Lee Norse* 100-1
  • DIN 51524 Part 2
  • Ford* M6C-32
  • Afnor* E 48-603
  • BF Goodrich* 0152 (except PM 500 Series)

*All trademarked images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use. All products advertised here are AMSOIL-engineered for use in the applications shown.


Use AMSOIL Shock Therapy Suspension Fluid in front forks and shocks on snowmobiles, dirt bikes, motorcycles, ATVs and other racing and recreational-use vehicles, as well as cars and trucks that require suspension systems that perform in the most extreme conditions. Agitate the fluid before use. Shock Therapy Suspension Fluid Light #5 is the preferred choice for winter use.

Use AMSOIL Shock Therapy Suspension Fluid Light #5 (STL) in suspension systems where less dampening and quicker rebounds are desired, including those made by Showa*, Kayaba*, Bilstein*, RydeFX*, Penske* and WP* forks; and RACETECH* (US1) and Custom Axis*.

Use Shock Therapy Medium #10 in suspension systems where more dampening control and slower rebounds are desired, including those made by Ohlin*, FOX*, RACETECH (US2), Koni* and WP shocks; and Harley-Davidson* forks that recommend type “E” or “B” fork oil.

Product Availability

AMSOIL Shock Therapy Suspension Fluids are available in quarts and 5-gallon pails.

Amsoil Product Warranty

AMSOIL products are backed by a Limited Liability Warranty. For complete information visit

Health & Safety

This product is not expected to cause health concerns when used for the intended application and according to the recommendations in the Safety Data Sheet (SDS). An SDS is available online at or upon request at 715-392-7101. Keep Out Of Reach Of Children. Recycle used oil and bottle.

Download Data Bulletin For Complete Product Information