What does the oil grade mean
Posted February 28, 2008 - 06:45 AM
Posted February 28, 2008 - 07:02 AM
Posted February 28, 2008 - 07:03 AM
The API/SAE designation for multi-grade oils includes two grade numbers; for example, 10W-30 designates a common multi-grade oil. Historically, the first number associated with the W (again 'W' is for Winter, not Weight) is not rated at any single temperature. The "10W" means that this oil can be pumped by your engine as well as a single-grade SAE 10 oil can be pumped. "5W" can be pumped at a lower temperature than "10W". "0W" can be pumped at a lower temperature than "5W", and thins less at temperatures above 99°C (210°F). The second number, 30, means that the viscosity of this multi-grade oil at 100°C (212°F) operating temperature corresponds to the viscosity of a single-grade 30 oil at same temperature. The governing SAE standard is called SAE J300. This "classic" method of defining the "W" rating has since been replaced with a more technical test where a "cold crank simulator" is used at increasingly lowered temps. A 0W oil is tested at -35°F, a 5W at -30°F and a 10W is tested at -25°F. The real-world ability of an oil to crank in the cold is diminished soon after put into service. The motor oil grade and viscosity to be used in a given vehicle is specified by the manufacturer of the vehicle (although some modern European cars now make no viscosity requirement), but can vary from country to country when climatic or mpg constraints come into play. Oil circulates through the piston oil rings to cool and lubricate the compression rings. Inside gasoline engines, the top compression ring is exposed to temperatures as high as 500°F.
Many new vehicles are marked to use 5W-20 oil (Honda, Ford, and more recently Toyota) which is not much thinner than a 30 weight oil. Nay-sayers of 20 weight oil's ability to protect engines should note that typically, 30 weight oils shear down into the 20 weight range anyway. Most engine wear is during start-up and warm-up period, where the thinner 20 weight oil's flow is desirable. Overall, lab test results of the wear metals contained in used oil samples show low or lower wear with 20 weight than 30 in applications it is specified for. Some ultra fuel efficient and hybrid vehicles are marked to use 0W-20 oil. For some selective mechanical problems with engines, using a more viscous oil can ameliorate the symptoms, i.e. changing from 5W-20 to 20W-50 may eliminate a knocking noise from the engine but doesn't solve the problem, just "masks" it. Excess amounts of oil consumed by an engine burning it can be addressed by using a thicker oil, a 10W-40 might not burn off as fast compared to a 5W-30. A newer product that also addresses this issue is the "High-Miles" oils now marketed. They tend to be slightly thick for their grades, contain extra additives and seal conditioners. Apparently the formulation of these oils works well in many instances.
Posted February 28, 2008 - 07:14 AM
Ktm recommend 10w50 the dealer 10w60
Theres your answer, pick one...not a lot of difference between the two
Posted February 28, 2008 - 08:49 AM
These are just generalizations, but in most of the US and Europe, 10W40 makes a good summer oil and 5W30 a good winter oil.
In the frozen north, maybe 10W30 in summer and 0W30 in winter.
In very hot climates, maybe a 15 or 20W50.
Posted February 28, 2008 - 08:53 AM