MX Tune is a motocross specific tune with balance, control, and bottoming resistance for the fastest speeds. It's firm suspension for maximum control and support for huge jumps, whoops and fast cornering. If you select the EBMX or MX spec, you’ll compromise a bit of trail plushness for improved bottoming resistance. RIDER WEIGHT SPECS: Sirris offers five weight ranges to choose from when selecting your MX Tune R46 shock. (Listed weight ranges are rider weight without riding gear on. 15 pounds of riding gear is calculated into the weight ranges) 120 lbs - 160 lbs (Light ships with 85 N/mm spring)160 lbs - 200 lbs (Medium ships with 95 N/mm spring)200 lbs - 240 lbs (Heavy ships with 105 N/mm spring)240 lbs - 280 lbs (X Heavy ships with 115 N/mm spring)280 lbs - 320 lbs (XX Heavy ships with 115 N/mm spring) PRODUCT SPECS: ArchitecturePiggyback, steel spring Stroke85 mm Length320 mm Weight3.9 lbs / 1.76 kg without spring Piston High flow Ø46 mm, CNC 6061 billet aluminum, type 3 hard anodized coating Piston bandHard band Shaft Ø16 mm OD chrome-plated, induction hardened steel, hollow, Ø 5.5 mm ID Shock bodySeamless 6061 aluminum, type 3 hard anodized coating, ACME thread Spring retainerSeamless 6061 aluminum, type 3 hard anodized coating, ACME thread, with locking feature, manual adjust Bottom outMCU bumper Top outRubber bumper DampingTunable compression and rebound ReservoirPressurized with floating piston AdjustersExternal compression and rebound adjustment SealsNBR