Open Gear Lubrication- Are you using the right open gear lubricant?

Wherever Open Gears are used, usually, they are directly exposed to the atmosphere. As described above, if we consider the equipment working in mining areas, we can imagine the continuous presence of dust, dirt, high-temperature conditions, etc.


Before going into details of Open Gear lubrication, let’s introduce some machines in which Open Gear Lubricants are used. This would give an idea about what we are going to see further.


It is also worth mentioning that, due to the low speeds, the exceptionally high torques to be transmitted, and barely attainable hydrodynamic conditions, the tooth flanks of gear drives are at serious risk of damage.


Furthermore, surface deformations tied to severe temperatures and loads, inaccuracies in the adjustment of pieces within the mechanism, insufficient lubricant supply, or even a poor selection of the lubricant can often lead to the same results. The choice of a proper lubricant is thus capital. 


Lubrication reliability best practices for open gears include selecting the proper lubricant and the correct application method to combat these challenges. Choosing wisely will help protect the gears from wear, increase uptime, and – in most cases – dramatically reduce gear set operating temperatures, lubricant consumption, energy consumption, and waste disposal.


This will lead to a cleaner, safer working environment. The right choice for open gears is a heavy-duty, high-viscosity lubricant with extreme pressure, anti-wear additive package. A lubricant with a Timken rating of 70 pounds or more reduces wear and extends gear life.


What Properties Are Required In An Open Gear Lubricant?

Industrial Lubricants are used in various applications, such as bearings, gearboxes, wire ropes, etc. But the properties required in lubricant change as per the application. In some applications, low viscosity & less tacky lubricant is preferred, while others may demand high viscosity and more tacky lubricant.

Lubricants should thus be selected based on operational parameters, surrounding atmospheric conditions, life expectancy, etc.


Following are the properties that an open gear lubricant should possess.

  • Tackiness- The applied lubricant should stick firmly to the Gears
  • Resistance to water washout and spray off.
  • Excellent load-carrying capability This should offer opposition against friction and model.
  • Cushioning ability – Vibration should be lowered. Open gear lubrication oil should not build up in the hearts of the gear tooth.


What parameters are essential when choosing a good lubricant?  

Gear applications heavily engage the lubricant used. Generally, these mechanisms operate at low-pitch line velocities and under heavy loads. However, the most current designs on industrial equipment need gears to transmit increasingly higher gears. As such, the following points are some of the most sought characteristics in a gear lubricant: 

  • Excellent adhesion properties
  • High resistance to water washout and spray-off 
  • High load-carrying capability, protecting against wear and variance  
  • Wear and corrosion protection  
  • Noise and vibration reduction properties  
  • Sprayability and ease of dispensability 
  • Additional properties, such as trainability or resistance to fling-off 

Open Gear Lubricant Standards

Several Industry specifications and standards are developed for Open Gear lubricants by American Gear Manufacturing Association (AGMA) and Many OEMs. The most widely used are AGMA 251.02 and US Steel 226 and 336.

Types Of Open Gear Lubricants

  • Asphaltic Type
  • Semi – Fluid Grease
  • Semi Fluid Grease Cut Backs
  • Gel Polymer Thickened Types
  • High Viscosity Synthetics

Asphaltic Type

They are formulated using high-viscosity residual compounds such as asphalt, bitumen, and a volatile solvent. Typically, these residual compounds have a viscosity of 643 CST or higher @ 100 deg C. After application, the solvent evaporates, leaving behind a dense lubricant coating. They are relatively cheap, perform well, and have an adhesive film. But has environmental concerns.


  • Potential to cause ozone layer depletion and cancer.
  • At lower temperatures, they tend to harden and peel off, whereas at a high temperature, they tend to be less dense.

Semi-Fluid Grease And Semi-Fluid Grease Cut Backs

They are formulated using medium-high base oil viscosity with some bitumen and asphalt. It also consists of Thickener and Additives and has NLGI 0 – 1. However, some products are manufactured using a solvent to improve their spray ability.

Gel Polymer Thickened Type

It has a polymeric thickener and solid lubricants. The film is thixotropic, which reduces friction to a minimum, and thus can be applied by standard intermittent spray systems, splash, and idler immersion systems.

These Open gear lubricants have excellent pump ability. Hence pumps and metering devices are subjected to less stress. Also, they perform well in dusty and dirty surroundings.


We have seen various types of lubricants for Open Gear applications. However, the selection of lubricant depends on the actual operating conditions of equipment and environmental factors.


Alpha bull lubricant has 7 years of excellence in lubrication for various industries. Our Technical team recommends the best suitable product by studying the applications and several factors.


We invite you to write to us to discuss your application and the most appropriate lubrication solution that Alphabull lubricant may offer.

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