How Heat and Friction Destroys Bearings

November 23, 2013

Heat and friction destroys bearings and is a common enemy of automobiles and bearings. They affect an automotive system from the inside and lead to problems such as wear and tear and bad fuel economy. Here, we discuss how these two factors work to destroy one of the smallest units of automobiles: the gears and bearings in transmissions and other components.

The most common types of bearings found in manual transmissions are plain, ball, roller, tapered roller, and needle. Learn how heat and friction destroys bearings.A Closer Look at How Heat and Friction Destroys Bearings in Manual Transmissions

There are five common types of bearings found in manual transmissions: plain, ball, roller, tapered roller, and needle. Plain bearings are those used on an engine’s lower end with no moving parts. These bearings are not that commonly used in modern manual transmissions now because they wear quickly and it’s difficult to maintain a pressurized system in a transmission. Here, an oil film usually develops to hold the two bearings together and reduce friction. However, since heat and friction destroys bearings in all types of applications, it bears mentioning.

Ball bearings, on the other hand, are very effective in tolerating radial and axial load combination. A lot of modern heavy-duty transmissions use bearings that can now accommodate heavier axial loads. In this scenario, heat and friction destroys bearings by adding these two forces, or loads at the same time.

Roller bearings are slightly similar to ball bearings except that they have hardened steel pins or rollers instead of balls. They are also better in supporting radial loads of any given size than roller bearings. Tapered roller bearings, on the other hand, are better at coping with severe thrust and radial loads. The way that heat and friction destroys bearings in these bearing types, is tied very closely to how the lubricant performs under these pressures and conditions.

Needle roller or small-diameter bearings are commonly used in manual transmissions between the shaft and the driven gears. They serve a very important role since they can withstand high-speed differences without causing friction and excessive heat transfer.

Unnecessary, heat and friction destroys bearings of manual transmissions.Role of Friction on Bearing Wear and Overall Car Performance

Friction’s most basic definition is the force that prevents smooth and easy movement of two moving surfaces in contact with each other. With friction comes wear and tear and thus the need for lubrication. In automobiles, the gears and bearings in manual transmissions are units that do a great amount of movement. Since redesigning the shaft and bearing of an already existing unit is not always an option, lubricants are used instead to reduce friction. Once you grasp an idea on how heat and friction destroys bearings, one can see how proper lubrication is the only option to add reliability.

Eliminating the heat and overcoming friction on moving parts, like the valves, pistons, and gears cut the lost energy that are a result of unnecessary friction. Due to friction, the power produced by an engine’s manual transmission is consumed in gear friction, brake friction, wind friction, and rolling friction of tires instead. Gear wear and bearing wear, moreover, is the cause behind the majority of most maintenance and repair demands for clutches, gear boxes, brakes, and even the whole automobile itself.

Bearings also play very big roles in other functions of a car. The differential, for example, is the part that works with the manual transmission to bring power from the engine to the axle responsible for turning the wheels. It generally runs on 2 tapered roller bearings with the differential shaft journals fitted by double sided contact bearings. Improper movement of these causes excessive rubbing of these parts and lead to shaft wear and differential failure.

The same also goes for power steering systems. Ball bearings wound their way into the car’s steering worm drive and press a channel inside the nut which forces the nut to move into the worm drive. Worm drives make use of recirculating ball bearings that help in reducing frictional forces. It also allows the force of the steering to be felt in the wheel. These bearings and its mechanism help with vehicle control and wear prevention. When the ball bearings are subjected to too much heat, it can lead to wear and tear in some of the parts and cause difficulties in steering precisely. Today, many power steering systems utilize a rack and pinion setup over the older worm drives. However, heat, friction and fluid loss are the leading causes of failure in these systems as well.

To put it simply, since heat and friction destroys bearings… reducing friction, heat and wear on bearings leads to less downtime, increased service life, and lower operating costs.

The question now is, “What is the best way to reduce heat and friction in these bearings and the parts they move?” Below are some possible options.


The use of oil or lubricants effectively reduces surface contact of bearings in manual transmissions. It is important to note, however, that using too much oil can  cause friction and power loss due to internal fluid friction. This sounds counter intuitive, however this is why you should always follow the manufacturer’s recommended fluid levels.

Since heat and friction destroys bearings... smaller bearings and special coatings are now being developed to reduce friction in manual transmissions.Smaller Bearings and Special Coatings in Manual Transmissions

Lately, engine designers have turned to using smaller bearings in order to cut surface area in manual transmissions. Together with this comes the introduction of special coatings that also reduce heat and friction. These products are usually polymer coatings that reduce friction by up to 50 percent. Coated bearings aid the stop-start systems of manual transmissions which is a huge cause of wear and tear on bearings.

At present, more and more types of bearings are continuously being developed to reduce friction as much as possible.

Using a quality metal treatment for your manual transmission can help as well. These products lessen heat and friction and also improves overall vehicle performance. A lubricating grease can also help protect bearings by providing lubricating qualities at wide range of temperatures.

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Tech Guy

Automotive enthusiast, passionate about Jeeps, hot-rods, turbos, performance, efficiency, diesels, fuels, high performance oils, additives and anything with an engine.