Lubrication of bearings is always an important issue. In Racing where bearings tend to run closely to their operational limits the lubrication can become critical. SKF has chosen many special greases and tested and proven these for different motorsport applications. Below are some examples of bearing applications requiring particular greases. SKF can supply suitable greased and sealed bearings for each of these applications. For more information about SKF greases, follow this link
In Racing wheel bearings tend to run close to their load limits while exposed to high temperatures from the braking systems and drive shaft. Rally and off-road cars may also expose the bearings to dirty or moist environments. Therefore the grease must tolerate high contact pressures and temperatures and have some capability to exclude dirt and water. One good example of a racing wheel bearing grease is the SKF LGHP2 or the SKF LGWA2.
Clutch release bearings
Clutch release bearings are often exposed to high temperatures, however mostly the loads are low. Only when the clutch is opened is the bearing carrying a significant load. Therefore the bearing requires grease which can withstand high temperatures, protect the rolling elements from sliding under low load conditions and high speed gradients. PTFE based greases are commonly used in these circumstances. One such grease is the SKF LGET2.
Sometimes the clutch will work in the opposite way loading the bearing to keep the clutch open and unloading when the clutch closes. In this case as the bearing is carrying load most of the time a PTFE grease is no longer suitable. Please contact SKF Racing for advice in this case.
Pilot bearings, typically sitting between engine and gearbox, have no net speed across the bearing when engine and gearbox are coupled (clutch closed) but can have high speeds when the clutch is closed. Also the speed gradients can be very high. The bearing will normally carry little or no load. Therefore the grease must protect the surfaces when they are running with no load, but must also be able to withstand high speed gradients. Grease such as the SKF LGHB2 may be suitable.
Kart axle unit bearings run at relatively low speed, low loads and low temperatures. However as the Kart is normally power limited it is important to reduce the friction losses from the grease as much as possible. Therefore SKF recommends thin grease such as SKF LGLT2 grease.
Motor Generator Unit Greases
MGU's are being adopted increasingly in Racing as Hybrid race cars are developed. Greases for these applications must be able to withstand high speed gradients and high temperatures however the loads are normally low. Please contact SKF Racing for advice in this case.
As an alternative to electrical KERS devices flywheel based devices are also being developed. As issue in this application is how to lubricate the bearings, particularly if placed in a vacuum. Lubrication in a vacuum at extreme speeds, with moderate loads and the potential of high temperatures from surrounding components is a difficult environment. Please contact SKF Racing for advice in this case.