Staburags NBU 12 vs Staburags NBU 8 EP: Heavy-duty bearing grease selection
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Staburags NBU 12 or Staburags NBU 8 EP?
Same thickener, different jobs. Both are barium complex greases on mineral oil, but Klüber documents Staburags NBU 12 (017052) for medium-speed rolling bearings exposed to humidity or ambient media, such as water pumps, wheel bearings, motors and wet textile processing equipment, from -15 to +130 °C with a high-viscosity base oil of about 220 mm²/s. Staburags NBU 8 EP (017105) is a rolling bearing and high-pressure grease with EP wear protection, used in traction motors, journal bearings, electric motors, pumps and tapered roller bearings, from -20 to +140 °C with a base oil of about 97 mm²/s and a speed factor of about 500,000 mm/min. The machine builder's specification decides; where none exists, speed and the dominant stress (media exposure versus high surface pressure) separate them.
The two greases side by side
| Property | Staburags NBU 12 | Staburags NBU 8 EP |
|---|---|---|
| Base oil | Mineral oil | Mineral oil |
| Thickener | Barium complex soap | Barium complex soap |
| Service temperature | -15 to +130 °C (+130 °C with continuous lubrication) | -20 to +140 °C |
| Worked penetration, DIN ISO 2137, 25 °C | 245 to 275 (0.1 mm) | 265 to 295 (0.1 mm), NLGI 2 |
| Base oil kinematic viscosity at 40 °C | approx. 220 mm²/s (approx. 19 at 100 °C) | approx. 97 mm²/s (approx. 11.5 at 100 °C) |
| Shear viscosity, 25 °C at 300 s⁻¹ | 9,000 to 15,000 mPas | 5,500 to 9,500 mPas |
| Dropping point, DIN ISO 2176 | 220 °C | 220 °C |
| Four-ball test, DIN 51350 | welding load 3,000 N | wear scar 1.8 mm at 1,000 N |
| Speed factor (n × dm) | approx. 350,000 mm/min | approx. 500,000 mm/min |
| FAG FE9 test, DIN 51821-2 | not published for this product | service life F50 100 h (1,500 N, 3,000 min⁻¹, 140 °C) |
| NSF H2 registration | 135 689 | 135 684 |
| Density at 20 °C | approx. 0.99 g/cm³ | approx. 0.96 g/cm³ |
| Colour | Brown | Beige |
| Minimum shelf life, unopened, dry and frost-free | approx. 60 months | approx. 60 months |
Scroll the table horizontally to view all columns.
Source: Klüber product information sheets STABURAGS NBU 4, 12 (article number 017052) and STABURAGS NBU 8 EP (article number 017105), plus the Klüber product page for STABURAGS NBU 8 EP. Klüber publishes these values as guide values; confirm against the datasheet supplied with your delivery.
Note the worked penetration: NBU 12 at 245 to 275 sits at the firm end of NLGI 2 and into NLGI 3 territory, while NBU 8 EP is a published NLGI 2. Klüber does not publish an NLGI class for NBU 12, so match the penetration range and the machine list rather than the class label.
Corrections to common descriptions
Comparison pages around the web describe NBU 12 as containing solid lubricants. The published product information for STABURAGS NBU 12 lists mineral oil and barium complex soap and no solid lubricant content; Klüber's solid-lubricant variant in this family carries a different name (STABURAGS NBU 12 ALTEMP). If your standard calls for a documented solid-lubricant grease, check the current product information before ordering.
Both products carry NSF H2 registrations. H2 means the lubricant may be used only where no contact with food is possible. For points where incidental food contact cannot be ruled out, neither product is the right category; specify an H1 registered lubricant instead.
Where each is documented in use
Klüber positions NBU 12 on medium-speed rolling bearings subject to humidity or ambient media, and states that the product resists very high specific surface pressure, corrosion, water, and many diluted alkaline and acid solutions. Documented applications: water pumps, wheel bearings, motors, and wet textile processing such as washing, mercerising and dyeing machines. NBU 12 is also offered in the Klübermatic automatic dispenser for automatic lubrication points.
NBU 8 EP is documented as a long-term grease for bearings subject to high specific loads, with good wear protection enhanced by the barium complex thickener, reliable corrosion protection and resistance to water. Documented applications: traction motors, journal bearings, electric motors, pumps, and tapered roller bearings. Its FE9 result documents 100 hours F50 at 140 °C, which supports the higher upper service temperature in long-term service.
Example: two bearings in one dyeing plant
A washing compartment bearing runs at moderate speed, constantly wet, with diluted alkali in the air: this is the documented NBU 12 profile, media resistance first. The drive-side spherical roller bearing of the same line sees shock loads through a gearbox and runs warm near 140 °C at a speed factor above 350,000 mm/min: the documented NBU 8 EP territory, EP wear protection and the higher speed factor matter more there. Same plant, both barium complex greases, chosen by stress factor rather than brand habit.
Speed and film thickness
The speed factors put numbers on the split. NBU 12's higher base oil viscosity builds a thicker film at low to medium speed, which is why it suits slower, wet, media-exposed points; pushed past about 350,000 mm/min it churns and runs hot. NBU 8 EP's lighter oil raises the practical speed factor to about 500,000 mm/min, and its EP wear protection covers the contact stress that comes with higher loads at those speeds. For a specific bearing, compute the speed factor from speed and pitch diameter and compare it with the table before deciding.
Both products are applied by brush, spatula or conventional metering systems, and both are barium complex greases: purge old grease thoroughly when changing over and do not mix them with sodium or lithium soap products without a compatibility check.
Common questions
Which one handles water and chemicals better?
Water resistance is documented for both. NBU 12's documentation goes further on media: resistance to corrosion, water and many diluted alkaline and acid solutions is part of its published profile, and its documented applications are wet textile processing equipment. If the dominant threat is washwater, humidity or chemical vapour, that is the documented match.
Which one is the extreme pressure grease?
NBU 8 EP. Its name and documentation say so: high-pressure grease, good wear protection with EP properties, and a published four-ball wear scar of 1.8 mm at 1,000 N. NBU 12's published four-ball figure is a welding load of 3,000 N, but Klüber documents it as a wear-resistant grease for media-exposed bearings rather than an EP grease for shock loads.
Are either of them suitable for food machinery?
Both carry NSF H2 registrations, which means use only where contact with food is impossible. Where incidental food contact can occur, move to an H1 registered product, for example the Klüberfood NH1 or Klübersynth UH1 lines, and verify the registration in the current NSF White Book.
Can I top up one with the other?
They share a thickener family, so a small crossover will not instantly gel, but the base oil viscosities differ by a factor of more than two and a mix gives you an undefined product. Purge the housing with the new grease and confirm the fill quantity the machine builder specifies.
Order the grease the machine list calls for
Send the product name, pack size (400 g cartridge or 1 kg can are the common sizes) and quantity. If you are choosing between the two for a specific bearing, include speed, temperature and the media the bearing sees, and we will check the fit against the current product information.
Manufacturer references
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