– Wheel bearing: definition
– Wheel bearing characteristics
– Wheel bearing maintenance
– Wheel bearings: prices and points of sale
Do you hear a dull humming noise in the cabin when you drive? It could be a defective wheel bearing. In this article, we give you all our advice on how to detect it, maintain it and, if necessary, have it replaced!
Wheel bearing: definition
The wheel bearing is a high-tech part that is part of the wheel axle and allows the wheel to rotate smoothly with the hub.
It has a circular shape made of treated steel and consists of 3 main parts:
– The outer ring :
It is a metal ring mounted tightly on the hub, the inner part of which is a raceway allowing balls to move. This raceway is in the shape of an inverted V, forming two oblique slopes opposing each other from the center to the outside of the ring.
– The inner ring:
These are two rings, the inner diameter of which accommodates the spindle (= wheel axle) and the outer diameter of which consists of a raceway accommodating the balls.
– The balls of rolling:
As their name indicates, the rolling balls are spherical and are inserted in two rows between the outer ring and the two inner rings. They allow the circular rotation of the inner rings with the fixed outer ring.
They are held together by a plastic cage that allows them to rotate; they are immersed in grease, and their water tightness is ensured by steel or plastic side guards.
Please note: The inner rings are held in place by the locking of the bearing in the hub and stub axle and the raceways opposing the two rows of balls and thus helping to eliminate play.
Wheel bearing characteristics
The wheel bearing must withstand various stresses:
– It must be durable and of high quality to withstand rotational speeds.
– It must resist thermal stresses, hence the quality of the steel and its treatments.
– It must withstand mechanical shocks (sidewalks, obstacles…)
– It must generate a minimum of operating noise; the raceways’ surface and the balls must be flawless.
A wheel bearing is defined by its inside diameter, outside diameter and width.
For example, a 25x47x12 bearing has an inner diameter of 25mm, an outer diameter of 47mm and a thickness of 12mm.
Wheel bearing maintenance
On modern vehicles, the wheel bearing does not require any special maintenance; however, it should be replaced if it makes an abnormal noise.
Note: If this is the case, the hub may heat up and, in the worst case, destroy the hub or the spindle, which may lead to an accident.
The wheel bearings are designed for a minimum life cycle of 100,000 km under normal conditions.
Violent shocks (accidents, sidewalks…) can cut the bearing, causing a dull whirring sound). In this case, the only solution is an immediate replacement.
Good to know: Contrary to what some professionals claim, it is unnecessary to replace bearings in pairs.
Wheel bearings: prices and points of sale
Costs vary greatly depending on the brand and type of vehicle (between $60 and $150).
Good to know: Rear-wheel bearings, which are smaller in size, are often less expensive than front-wheel bearings (20 to 30% lower prices).
Although many suppliers (manufacturers, independent distributors of car parts, car centres, specialized websites), your supplier can be your car mechanic, who will necessarily replace your vehicle’s wheel bearing.
Count on $50 to $80 of labour for an operation that will last at most one hour and a half. Indeed, it is a technical and delicate operation requiring specific equipment.
Caution: the high pressure required to mount the bearing can lead to its deterioration or that of the wheel hub. Indeed, a very fragile magnetic strip from the bearing can be exposed during the replacements or damaged during the assembly, which systematically leads to the anti-lock wheel system’s malfunctioning.