By Lukeron Lubricants · Last updated
Quick answer
Grease is oil held in a thickener, with additives for wear, rust and load. It stays where you put it, seals against dust and water and does not drip, which is why bearings, wheel hubs and chassis points use it. Types are named by the thickener: calcium, lithium, lithium complex, calcium sulfonate and others. NLGI 2 is the usual grade, and a higher NLGI number means stiffer, not better. For a bearing, the manual or the bearing maker decides the grease.
Common greases and where they are used
| Grease | Usually used for | Lukeron grease |
|---|---|---|
| Calcium | Wheel bearings, chassis points, universal joints, daily workshop use | SPL Calcium Grease AP-3 / MP-3 |
| Lithium | Wheel bearings, CV joints and ball joints in cars and SUVs | SPL Auto Lithium Grease AP-3 / MP-3 |
| Lithium complex | High-performance bearings, extended-drain use | SPL Lithium Complex Grease 2.5 |
| Calcium sulfonate | High-load industrial bearings, marine, construction | Calcium Sulfonate Grease NLGI 2 |
| High-temperature non-melt | Furnace bearings, ovens and kilns | High-Temp Non-Melt Grease NLGI 0 |
General guidance only. Follow the machine or bearing maker's manual for grease type and NLGI grade.
Grease is one of the most used lubricants in workshops and plants, and one of the least understood. People search for what grease is, how it differs from oil, which grease to use on a bearing and what it should cost. This guide answers those questions in plain words.
What is grease?
Grease is oil held in a thickener. A base oil does the lubricating. A thickener holds the oil in place like a sponge, and additives add protection against wear, rust and heavy load. The result is a soft, buttery lubricant that stays where you put it.
What grease is made of
- Base oil: the part that lubricates. It can be mineral or synthetic.
- Thickener: the part that holds the oil. It is often a soap, such as calcium or lithium, and the type of thickener names the grease, for example calcium grease or lithium grease.
- Additives: extreme pressure and anti-wear additives, rust protection, and in some greases solid lubricants such as moly or graphite.
Grease or oil: what is the difference?
Oil flows. It carries heat away and returns to the surface it lubricates. Grease stays in place. It seals against dust and water, does not drip, and keeps working where oil would leak out or where you cannot keep an oil bath. That is why wheel bearings, chassis points and many industrial bearings use grease, and enclosed gearboxes usually use oil. Our guide on gear oil vs grease explains the choice for gearboxes.
Common types of grease and where they are used
- Calcium grease: wheel bearings, chassis points and universal joints, and daily workshop use.
- Lithium grease: wheel bearings, CV joints and ball joints in cars and SUVs.
- Lithium complex grease: high-performance bearings, including extended-drain use.
- Calcium sulfonate grease: high-load industrial bearings, marine and construction equipment.
- Sodium wheel bearing grease: high-temperature wheel bearings in trucks and buses.
- High-temperature non-melt grease: furnace bearings, ovens and kilns.
- Moly and graphite greases: shock loads, open gears, wire ropes and sliding surfaces.
What NLGI grade means
NLGI is a number from 000 to 6 that shows how stiff a grease is. NLGI 2 is the standard grade for most bearings and general greasing. A higher number means a stiffer grease, not a better one. Our NLGI guide explains each grade.
Bearing grease: how to choose
For a bearing, the maker's manual or the bearing maker decides the grease. They name the NLGI grade, the base oil thickness and the temperature range. As a general guide, a hot, fast bearing needs a grease made for heat and speed, such as a lithium complex or a high-temperature grease. A slow bearing under heavy load needs an extreme pressure grease, sometimes with moly. A wheel bearing needs a grease made for wheel bearings. If you are not sure, send us the machine, the bearing and the working temperature.
Grease price: why it differs
Two greases can cost very different amounts. The price depends on the type of thickener, the base oil, the additives such as moly or extreme pressure additive, the NLGI grade and the pack size. Greases come in packs from small tubs to 180 kg drums, and a larger pack costs less per kilogram. GST is added on top. Because raw material costs move, we quote the current price for your grease, pack and quantity. Send us those three details and we reply within 1 to 2 business days.
Mistakes to avoid
- Mixing greases with different thickeners. Some thickeners do not mix and the grease can soften or run.
- Using the wrong NLGI grade. A stiff grease can leave a gearbox or a centralised system starved, and a soft one can run out of a bearing.
- Adding too much grease. Overfilling a bearing can make it run hot.
- Using grease where the maker names oil.
- Using a dirty grease gun or nipple, which pushes dirt into the bearing.
How to choose in four steps
- Read the manual or bearing data for the NLGI grade and the temperature.
- Choose the grease type that suits the load, the speed and the heat.
- Check that the new grease is compatible with the old one, or clean the old one out first.
- If you are unsure, send us the machine and the working conditions and our team will help you choose.