TRIZONE EXPLAINED
Trizone Technology
WHAT THE GEARBOX NEEDS
Just behind the clutch lies one more high-stress zone that the oil must also protect: the gearbox. The gearbox is a further area of the motorcycle where high precision meets high stress. High precision means compact design, tight tolerances and the use of finely machined components for ultimate engine performance.
Increased stress comes through ever increasing speed, power and narrower gear sets. These narrow gear sets mean huge pressures between the meshing teeth - adding additional stress to the lubricant. Heat uncoils the polymers used in multi-grade oils and makes it more vulnerable to the high shearing action of the gears trying to tear it apart. Four-stroke motorcycle oils demand specially selected components to resist shear and maintain load carrying capacity.
During operation, the faces of the gears scrape against each other under load: this can cause scuffing or scoring of the gears, the teeth can knock and hammer against one-another.
This creates sub surface stresses within the gears that can weaken the hardening on the surface of the teeth making them vulnerable to pitting, the removal of material from the surface.
Castrol four-stroke motorcycle oils incorporate phosphorous-based anti-wear additives; active ingredients help to prevent metal-to-metal contact between the meshing gears. Ultra-low viscosities - such as the 0W-30 commonly used in cars - can impact the protection and performance of the gears.
In motorcycles higher viscosities are needed to provide full gear protection - but without compromising on the flow or friction properties needed for engine and clutch performance.
