Since I posted on another thread on bearings, I thought the following would be helpful for wheel bearing life.
In use the wheel breaths and this can affect bearing life particularly if parked for a couple of weeks or more.
So how does the wheel breathe, it breathes due changes in temperature. When applying the brakes the hub heats up, the air inside the hub expands and breathes out through the seal and when it cools down it breathes in.
The air coming in brings in a certain amount of moisture and this moisture will condense on the inner walls of the wheel.
When the wheel is heated up again it is not hot enough to vaporise all of the water and on cooling more water is added until over a few cycles small droplets form and it is these droplets when they get into the bearing which will form small rust lines if left sitting. Commonly visible as dark staining at roller spacing. This rust etching forms a stress point which dramatically lowers the fatigue life and is most common with a rough running bearing.
There are a couple of simple actions that can reduce the build up of water droplets on the inner walls of the wheels.
1. Fly lots then the water does not have sufficient time to etch the bearing tracks before it is wiped away by the bearing rollers turning. (Best solution)
2. By applying a thin layer of grease to all of the exposed inner surfaces of the wheel this will reduce water droplets forming on the surface keeping the moisture suspended in the air.
Hope this helps
Rob
In use the wheel breaths and this can affect bearing life particularly if parked for a couple of weeks or more.
So how does the wheel breathe, it breathes due changes in temperature. When applying the brakes the hub heats up, the air inside the hub expands and breathes out through the seal and when it cools down it breathes in.
The air coming in brings in a certain amount of moisture and this moisture will condense on the inner walls of the wheel.
When the wheel is heated up again it is not hot enough to vaporise all of the water and on cooling more water is added until over a few cycles small droplets form and it is these droplets when they get into the bearing which will form small rust lines if left sitting. Commonly visible as dark staining at roller spacing. This rust etching forms a stress point which dramatically lowers the fatigue life and is most common with a rough running bearing.
There are a couple of simple actions that can reduce the build up of water droplets on the inner walls of the wheels.
1. Fly lots then the water does not have sufficient time to etch the bearing tracks before it is wiped away by the bearing rollers turning. (Best solution)
2. By applying a thin layer of grease to all of the exposed inner surfaces of the wheel this will reduce water droplets forming on the surface keeping the moisture suspended in the air.
Hope this helps
Rob