Red Line's LightWeight 5WT Suspension Fluid (part 91122) is a 16 oz bottle of synthetic damper oil for shock absorbers and motorcycle forks. The manufacturer positions it as a popular, more stable replacement for most 7wt OE suspension fluids, so it suits owners whose stock fluid thins too much when hot or thickens in the cold. It also is very low foaming and provides good seal lubricity and antiwear properties, which helps shock and fork internals last longer. Sprint car, CORR and SCORE off-road, and motocross teams use it for consistent damping under heavy use.
The fluid's viscosity index of 560 means it changes less with temperature than many conventional fluids, which keeps damping more predictable on track or trail. Because it is a damper fluid rather than a vehicle-specific part, fitment depends on your fork or shock design, and the manufacturer notes that matching viscosity at your operating temperature is the best way to choose a weight. Searching for a 5wt fork oil, 5W shock fluid, or Red Line 91122 replacement for stock 7wt suspension oil will bring you to this exact grade.
The manufacturer describes it as a popular direct replacement for most 7wt OE suspension fluids that offers greater stability. Confirm your damper's specified fluid before swapping.
Yes. The manufacturer states that Red Line suspension fluids can be blended in any proportion to reach an intermediate viscosity.
The manufacturer notes there is no clear standard behind the "W" rating, so matching viscosity at your operating temperature is the better method. The manufacturer will help select a viscosity if you contact them.
Difficulty is moderate and depends on the design. Many motorcycle forks need to be removed from the bike to drain and refill, and owners on user forums report that pumping the fork slider several times helps expel oil trapped inside before refilling. Fill height is set by measuring from the top of the fork tube with the forks collapsed and springs removed, so check your service manual's target. Owners also warn that drain bolts can strip if the wrong tool is used. Sealed or cartridge-style dampers are not easily user-serviceable, so fluid changes there are limited.
