Rocker arm or also known as cam follower is a piece of metal that follows the cam (SOHC or DOHC) to transfer the lift and close instruction from the cam bump to the valve.
Conventional rocker arm does not have a roller. See picture below.
So, what is the advantage of the roller rocker arm?
The most obvious advantage of using roller rocker arm is that it can minimise the mechanical lost from the crankshaft to the cam to the valve. Roller provides better movement of the cam to the rocker arm and at the same time minimise the friction between that two part (cam and rocker arm).
When mechanical lost is minimised, we can get more power transferred to the wheel. So, in theory, you can get more torque and horsepower by installing this roller rocker arm.
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