Some skaters use the WD-40 as a lubricant for the bearings of their roller skates. Is it a right choice?
WHAT IS WD-40?
WD-40 is a well-known product and used in many areas, from the home to the workshop, from outdoor to indoor activities. But what exactly is WD-40? WD-40 is a multipurpose water repellent and protective spray that is used to protect and lubricate metal parts, such as bolts, hinges, electric chains, locks, and more. But that's not all: WD-40 is also used as a rust inhibitor, cleaner, unlocker and lubricant for plastic and rubber parts.
The name "WD-40" comes from "Water Displacement, 40th formula". It was developed as a multipurpose water repellent by Norm Larsen of the Rocket Chemical Company of San Diego (CA, USA), in 1953. The number 40 derives from the fact that it is the fortieth formula tested by the inventor. Larsen was trying to find an applicable formula as an anticorrosion and water repellent product for the protection of nuclear missiles. The initial use was in fact the protection of some parts of the Atlas missiles from the possible formation of rust and corrosion. WD-40 was marketed for civilian uses starting in 1958 in San Diego, enjoying great success in home and hobby applications.
Today, the product formula has been slightly modified and contains less ingredients, but the name remained the same. It is sold in spray cans and is easy to apply to any surface. In summary, WD-40 is a versatile and useful product in many areas, but it is important to use it correctly and understand its limits. With its ability to protect and lubricate metal, plastic and rubber parts, WD-40 is a highly regarded and indispensable product for many DIY, mechanical and outdoor enthusiasts.
USE OF WD-40 IN SKATING
Some skaters use WD-40 as a lubricant for the bearings of their skates, as it is a product that is comfortable to carry and use, very penetrating, given the low viscosity and low surface tension that characterize it, it is immediately effective and able to reduce the resistance to rotation of the bearings. Furthermore, the product is used to "wash" the bearings themselves, spraying it inside them and thus facilitating the escape of dirt particles.
IS WD-40 EFFECTIVE AS A LUBRICANT IN SKATING?
In summary, our answer is: no.
WD-40 it is not the most suitable product for lubricating skating bearings. While it can be used as an all-purpose water repellent/lubricant, WD-40 was not specifically developed to lubricate ball bearings, such as those used in roller skates or inline skates.
Specifically, the reasons , both mechanical and chemical, are as follows:
- A lubricant possess a viscosity suited to the specific application for which it is used. In fact, viscosity is the parameter that most influences the so-called Stribeck curve of a mechanical system in motion in the presence of a lubricant. The Stribeck curve is a relationship between the coefficient of friction and the sliding speed in a tribological system, i.e. a system involving contact between two surfaces in relative motion. The Stribeck curve shows that the coefficient of friction between two surfaces depends on the speed of sliding between them. In particular, the curve shows that the coefficient of friction decreases with increasing sliding speed until it reaches a minimum value, after which the coefficient of friction increases again with increasing sliding speed. In the following figure, the area A, with a high coefficient of friction, is called the "zone of mixed friction": the surfaces are in direct contact and the friction is due to forces of adhesion and deformation of the surfaces. Zone B, where the friction coefficient is lower, is called the "elastohydrodynamic lubrication zone" (ZLE): in this condition, the lubricant forms a film which minimizes the friction forces present. The rise of the curve in this area can be attributed to the viscous dissipation effects acting in the lubricant itself.
The objective is therefore to make the bearings work at the minimum point of the curve, a condition which allows optimizing the efficiency of the system. To obtain this result, since the rotational speed range of bearings in skating is known, a lubricant with the right viscosity must be chosen. For example, the figure below shows how the choice of a lubricant with too low, correct and too high viscosity affects the frictional force developed by a bearing in roller skating.
The lubricant with the right characteristics, in the previous figure, is the one with an intermediate viscosity, represented by the blue curve. The green colored curve represents the behavior of a lubricant that is too viscous for the expected working conditions (e.g. a grease): at the average rotation speed of a skating bearing, the friction present will be greater, mainly due to dissipation viscose in the lubricant. Conversely, the red curve represents the behavior of the system considered in the case of a lubricant with too low viscosity: the friction present will be greater than in the ideal condition, this time due to the lack of formation of a continuous film of lubricant able to isolate the parts in motion. The conclusion is that WD-40 does not necessarily have an optimal viscosity value, simply because it was not designed on the basis of this criterion. Therefore, in general, it is better to opt for a lubricant whose viscosity has been specifically chosen for the application of interest to us.
- A reason of a chemical nature that suggests opting for lubricants developed specifically for use with steel ball bearings is that these lubricants contain components capable of guaranteeing chemical anchoring of the lubricating and protective substances present in the their composition, guaranteeing optimal conditions as regards resistance to oxidation and better maintenance of the lubrication characteristics over time.
SO, WHICH OIL SHOULD YOU USE?
There are many oils on the market that can guarantee excellent performance as regards the specific use in the skating sector. Among these, there are our oils Speed Oil or Speed Oil Nano, high quality products, developed on the based on the theoretical background set out above, based on our experience and feedback from our customers.
CONCLUSIONS
In summary, if you want to keep the bearings of your skates in top condition, it is best to avoid using WD-40 as a lubricant and instead choose a specific lubricant for bearings. This makes it possible to minimize the friction forces present, to improve the duration of the lubricating effect and to protect the bearings from corrosion phenomena.