Question.
What does the API rating mean and how do you tell what is needed for your application, i.e.; Harley motorcycles, Truck etc.?
Answer By Spectro Performance Oils.
To ensure quality levels and compatibility oils have a “rating” system to help consumers decide what oil is right for their vehicle. There are several organizations that rate oil for specific types of applications, with the key one being JASO (Japanese standards for metric bikes), the SAE and API for everywhere else. The rating system makes sure that particular oil meets certain lubrication criteria (an example would be zddp and phosphorus levels). Having a higher rating such as SM vs SG doesn’t necessarily make that oil better, just a different formula and additive package. The easiest way to decide what oil rating is right for your vehicle is to check the owners manual or with the vehicle manufacturer. Since the 1960’s, they will spec a specific rating for the vehicle such as SG, SL or SM for American vehicles, and JASO MA or MA-2 for metric vehicles.
