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Bel-Ray Specialty Lubricants: Tech Notes, Vol 2, Issue 6

June, 2011


 Bel-Ray Suspension Fluids

Most common dirt bike suspension systems are exposed to harsh conditions.  The Bel-Ray suspension fluid range has some advantages that can be easily overlooked when compared to other brand equivalents. 

Bel-Ray High Performance Fork Oil uses carefully selected high viscosity base oils to reduce stiction and fade, for smoother operation over a wide temperature range. Added into the mix are anti-wear additives that extend the life of the suspension tubes and sliders and an anti-foaming agent which eliminates any build up of air into the fluid for a more consistent dampening feel. Bel-Ray Fork Oil is recommended as a great replacement for OEM and high performance tuning, due to its consistency in staying true to the OEM specifications. In some recent research, other popular manufactures claiming to be a certain weight, have actually been found to be almost twice the viscosity weight of the equivalent Bel-Ray product. In this case, if a racer that had spent a lot of money getting their suspension tuned went and put in this alternative fluid, their suspension feel would be unrecognizable compared to the tuned setup. Bel-Ray Fork

Oil is designed to suit all standard cartridge type forks on street, off-road and ATV bikes; it also has an extensive weight range from 2.5W to 30W that will suit the lightest mini-bike rider, right through to the heaviest Harley Davidson on the road.

Bel-Ray HVI Racing Suspension Fluid is specifically formulated to withstand the excessive heat that a rear shock builds up over the duration of a race. It has very similar additives to the Bel-Ray Performance Fork Oil with anti-foam and anti-wear agents, but the difference lies with its high viscosity capabilities. HVI stands for High Viscosity Index, meaning that it is designed with a very high viscosity index number eliminating fade under the most extreme and demanding race conditions. In 2010, an Australian rider won every major Off-Road event in Australia including the great Finke Desert race, which has a 50 mile long whoop section that is done in both

directions. That race alone has been known to have had shock units collapse during the event due to the extreme conditions and heat. Bel-Ray HVI fixed any fading or failure problems for the rider. Like The Fork Fluid, Bel-Ray HVI Racing suspension fluid is a great replacement for OEM products and comes in 3W, 5W, 10W and 15W.

So when you decide it’s time to make your machine handle the ride a little better, look no further than these two great Bel-Ray products.


Grease Selection–Viscosity of Base Oils & NLG Grades

Base Oil Viscosity

The most important property of any lubricant is viscosity. A common mistake when selecting grease is to confuse the grease consistency with the base oil viscosity. Because the majority of grease-lubricated applications are element bearings, one should consider viscosity selection for those applications. While most would use EP 220 gear oil for an oil-lubricated electric motor bearing, many people will use grease containing that same oil for an identical grease-lubricated bearing. There are several common methods for determining minimum and optimum viscosity requirements for element bearings, most of which use speed factors, commonly denoted as DN or dn value. Speed factors account for the surface speed of the bearing elements and are determined by the following formulas:

DN = (rpm) * ((bearing bore + outside diameter) in mm / 2)

Knowing the speed factor value and estimated operating temperature, the minimum viscosity requirement can be read directly from charts like Figure 1. Figure 1 assumes the base oil’s viscosity index as 100. The minimum viscosity value in Figure 1 is not the viscosity of the oil you select, unless the load is very low. You need to double the minimum viscosity for a normal load or triple the minimum viscosity for a heavy load. The increased viscosity assures you will have good oil film thickness, which will provide maximum bearing life.

The following table is also recommended based on DN value.

Table 1
DN Suggested Viscosity of
Base Oil, cSt @ 40°C
< 100,000 > 460
100,000 220
300,000 150
500,000 100
600,000 68
800,000 32
1,000,000 or higher < 15

Grease Consistency

The consistency of grease is controlled by the thickener concentration, thickener type and the viscosity of the base oil. Even though base oil viscosity affects consistency, it is important to note that grease can have a high consistency and a low base oil viscosity or vice versa. The NLGI has established a scale to indicate grease consistency which ranges from grades 000 (semifluid) to 6 (block grease). The most common NLGI grade is two and is recommended for most applications.

For bearings, speed factor and operating temperature can be used to determine the best consistency or NLGI grade for a given application. It may seem counterintuitive, but higher speed factors require higher consistency greases. Table 2 provides a general guide to selecting NLGI grade based on speed factor and operating temperature.

Table 2
Operating Temperature DN (Speed Factor) NLGI No. *

-30 to 100°F

0 - 75,000 1
75,000 - 150,000 2
150,000 - 300,000 2

0 to 150°F

0 - 75,000 2
75,000 - 150,000 2
150,000 - 300,000 3
100 to 275°F 0 - 75,000 2
75,000 - 150,000 3
150,000 - 300,000 3
* Depends on other factors as well, including bearing type, thickener
type, base oil viscosity and base oil type.


Lubricating at “Zero” Cost

When you take into account the cost of mining equipment, the lubricant to protect these assets could be one of the most important items you include in your maintenance budget. Due to the high values involved and the importance of the equipment uptime the equipment should operate with a “daily diet” of high-performance lubricants.

In general, the maintenance budget of many mining operations consists of a maximum of 3% for acquisition of lubricants. However, the real cost of the lubricants may be much lower if they can reduce energy costs and maintenance costs. You may be lubricating at “Zero” cost.

The annual energy cost for a 250hp motor running 24 hours/day, 7 days/week, 52-weeks/ year is $90,504.96. A 7.6% reduction in energy consumption on a piece of equipment driven by a 250hp motor saves $6,878.38/year; this assumes that the energy cost is $0.05/Kwhr and that the motor efficiency is 0.9 .

It is generally understood in the lubrication community that 60% of all mechanical failures are due to inadequate or improper lubrication practices.

The cost of lubricant(s) used on any rotating piece of equipment is an insignificant fraction of the total maintenance cost. However, the quality of the lubricant impacts the largest costs making up the budget, such as energy consumption, MRO (Maintenance Repair & Overhaul) plus component replacement costs and the cost of downtime associated with such repairs.  What all maintenance managers should pursue is a reduction in the final cost per ton produced. Bel Ray products, with proven efficiency in the field, can provide cost savings and efficiency increases for maintenance operations around the world.  Contact your Bel-Ray representative to determine the optimal lubricant choices for specific equipment and operating conditions.  Maximize efficiency and equipment protection with Bel-Ray lubricants.

Cost Savings Items % of total Budget
Annual Energy Costs 9%
General Maintenance Costs (including
replacement or repair of components)
Cost of Lubricant 0.008%