Learn about lubes
Viscosity classifications
Viscosity is the single most important property in selecting a lubricant. Three scales cover the products we make: SAE J300 for engine oils, the SAE gear scale for axles and transmissions, and ISO VG for industrial oils.
Engine oils — SAE J300
The most widely used system for engine oil viscosity classification is the one established by the Society of Automotive Engineers in the USA. SAE has established that twelve viscosity grades are suitable for engine lubricating oils. The physical requirements are described in SAE J300, which engine manufacturers use to determine the grades suitable for their engines.
Grades carrying the letter W are intended for use at lower temperatures and are based on maximum low-temperature viscosity limits as well as a minimum viscosity at 100 °C. Grades without a W are based on viscosity at 100 °C and a minimum high-shear-rate viscosity at 150 °C. A multigrade oil such as 15W-40 satisfies a W grade at low temperature and a non-W grade at high temperature.
| SAE grade | Cranking (cP) max at °C | Pumping (cP) max, no yield stress, at °C | Kinematic (cSt) at 100°C min | Kinematic (cSt) at 100°C max | High shear (cP) at 150°C min |
|---|---|---|---|---|---|
| 0W | 6 200 at −35 | 60 000 at −40 | 3.8 | — | — |
| 5W | 6 600 at −30 | 60 000 at −35 | 3.8 | — | — |
| 10W | 7 000 at −25 | 60 000 at −30 | 4.1 | — | — |
| 15W | 7 000 at −20 | 60 000 at −25 | 5.6 | — | — |
| 20W | 9 500 at −15 | 60 000 at −20 | 5.6 | — | — |
| 25W | 13 000 at −10 | 60 000 at −15 | 9.3 | — | — |
| 20 | — | — | 5.6 | <9.3 | 2.6 |
| 30 | — | — | 9.3 | <12.5 | 2.9 |
| 40 | — | — | 12.5 | <16.3 | 2.9 (0W-40, 5W-40, 10W-40) |
| 40 | — | — | 12.5 | <16.3 | 3.7 (15W-40, 20W-40, 25W-40, 40) |
| 50 | — | — | 16.3 | <21.9 | 3.7 |
| 60 | — | — | 21.9 | <26.1 | 3.7 |
Test methods: cranking ASTM D5293; pumping ASTM D4684 (any detectable yield stress is a failure regardless of viscosity); kinematic ASTM D445; high shear rate ASTM D4683, ASTM D4741 or CEC-L-36-A-90. All values are critical specifications as defined by ASTM D3244.
Automotive gear lubricants — SAE
Gear lubricant classification is based on viscosity measured at low and high temperatures. High-temperature values are determined by ASTM D445; low-temperature values by ASTM D2983, the Brookfield viscometer method for apparent viscosity at low temperature, measured in mPa·s.
| SAE grade | Max temperature (°C) for viscosity of 150 000 mPa·s | Viscosity at 100°C min | Viscosity at 100°C max |
|---|---|---|---|
| 70W | −55 | 4.1 | — |
| 75W | −40 | 4.1 | — |
| 80W | −26 | 7.0 | — |
| 85W | −12 | 11.0 | — |
| 90 | — | 13.5 | 24 |
| 140 | — | 24.0 | 41 |
| 250 | — | 41.0 | — |
Low temperature values by ASTM D2983 (Brookfield viscometer, mPa·s); high temperature values by ASTM D445. A multigrade gear oil meets a W grade at low temperature and a non-W grade at high temperature.
Industrial lubricants — ISO VG
The ISO viscosity classification uses mm²/s (cSt) and relates to viscosity at 40 °C. It consists of a series of 18 viscosity brackets between 1.98 and 1650 mm²/s, each defined by a number that is the mid-point of the bracket.
| ISO VG | Minimum (mm²/s at 40°C) | Mid-point | Maximum |
|---|---|---|---|
| 2 | 1.98 | 2.20 | 2.42 |
| 3 | 2.88 | 3.20 | 3.52 |
| 5 | 4.14 | 4.60 | 5.06 |
| 7 | 6.12 | 6.80 | 7.48 |
| 10 | 9.00 | 10.0 | 11.0 |
| 15 | 13.5 | 15.0 | 16.5 |
| 22 | 19.8 | 22.0 | 24.2 |
| 32 | 28.8 | 32.0 | 35.2 |
| 46 | 41.4 | 46.0 | 50.6 |
| 68 | 61.2 | 68.0 | 74.8 |
| 100 | 90.0 | 100 | 110 |
| 150 | 135 | 150 | 165 |
| 220 | 198 | 220 | 242 |
| 320 | 288 | 320 | 352 |
| 460 | 414 | 460 | 506 |
| 680 | 612 | 680 | 748 |
| 1000 | 900 | 1000 | 1100 |
| 1500 | 1350 | 1500 | 1650 |
The ISO scale is a series of 18 brackets between 1.98 and 1650 mm²/s, measured at 40°C.
Need a specific grade?
Our range covers 0W-40 through to SAE 250 and ISO VG 32 to 460.
More technical guides
Reference material for choosing and handling lubricants.