Every lubricant starts with a base oil — the raw material that makes up 70-95% of the finished product, before additives are blended in. The American Petroleum Institute (API) classifies base oils into five groups based on how they're refined and what they're made of. Understanding this classification tells you more about real oil quality than the word "synthetic" alone.
Group I — solvent-refined mineral oil
The least processed category, refined from crude oil using solvent extraction. Group I oils have a wider, less uniform mix of molecule types than higher groups, which means more variability in performance — but they remain the most widely available and cost-effective base oil worldwide, and are entirely suitable for standard automotive and industrial applications in moderate operating conditions. A large share of India's own refining capacity, and much of what's exported to price-sensitive markets across Africa and South Asia, is Group I.
Group II — hydroprocessed mineral oil
Refined using hydrogen treatment instead of (or in addition to) solvent extraction, producing a purer, more uniform oil with better oxidation stability and a cleaner appearance than Group I. Group II has become the dominant base oil category in North America and is increasingly available globally as refining technology spreads.
Group III — severely hydrocracked oil
Processed even further, to the point that its performance characteristics rival true synthetics — which is exactly why Group III oils are legally marketed as "synthetic" in most jurisdictions, even though they originate from crude oil like Group I and II. Group III is the base oil behind most "full synthetic" automotive oils on the market today.
Group IV and V — true synthetics
Group IV is PAO (polyalphaolefin), built by chemically synthesizing molecules from scratch rather than refining crude oil. Group V covers everything else — esters and other specialty synthetic fluids, typically used in small amounts blended with other groups rather than as a standalone base oil.
Why this matters when you're sourcing
The base oil group behind a product tells you more about its real performance ceiling than the marketing language on the label. Lukeron can procure across all base oil groups — Group I, II, III, and beyond — per customer requirement, formulated with certified additive packages to match. Tell us what performance tier your market needs, and we'll source and formulate to match it.
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