Porsche Wheel Bearing - NTN 99905909800

Product Information

Wheel bearings support the vehicle's weight and reduce rotational friction, located within the wheel hub/spindle. European car manufacturers typically use three types of wheel bearings: unsealed, sealed press-in, and wheel bearing/hub assemblies.

Unsealed bearings, common in pre-1990 cars, require regular greasing, while sealed bearings, used from the 1990s onward, are maintenance-free and must be replaced when worn. The most modern approach integrates the wheel bearing into the hub assembly, simplifying replacement by bolting in a new unit.

Signs of failure include a grinding noise, which worsens over time. Diagnosing involves lifting the car to check for wheel play and noise. Replacement processes differ: unsealed bearings need cleaning and proper alignment, sealed bearings require pressing out, and hub assemblies are straightforward to unbolt and replace. Correct torque application is vital for all types to prevent premature failure.

• Grinding or growling: A bad wheel bearing will first reveal itself by making a growling or grinding noise when unloaded, IE if turning right, the right side will make noise. Eventually, as it gets worse, so will the sound until it’s replaced
• Play in the wheel: With the wheel off the ground, you will detect play from a worn wheel bearing. This is because the internal bearings have worn away and are no longer perfectly tight.
• Vibration or wobble: While much less frequent, if a wheel bearing is very bad or has an excessive amount of play in it, it will cause issues with the vehicle's handling, including vibration or wobble noticeably through the steering wheel.
• Uneven Tire Wear: A faulty Wheel Bearing can adversely affect tire wear and cause uneven wear across the tire contact patch.
• ABS warning light: If you are chasing an ABS issue and you have sorted out the sensors, it’s not impossible that damage has occurred to the ABS tone ring inside of the wheel bearing. If you have a single corner fault but the ABS sensor checks out, replace the wheel bearing and in turn the tone ring.

About NTN

The NTN Company started when backer, Noboru Niwa, sales company, Tomoe Trading Co., and engineer Jiro Nishizono joined together in designing and manufacturing the first NTN ball bearings, in 1918. Many years later the new head of NTN insisted that manufacturing be located within the same market as it was sold, thus NTN Bearing Corporation of America was created in 1963. Today NTN is proficient in the production of ball bearings, spherical, tapered, cylindrical, needle roller bearings, and automotive constant velocity joints. In fact NTN has the largest share of the global market for axle bearings and is a trusted supplier of OEM (original equipment manufacturer) bearings to many of today’s car manufacturers. NTN’s devotion to high standards has earned the company numerous awards for quality from clients, such as, Caterpillar, Ford Motor Company, Detroit Diesel, Navistar International Corporation, Twin Disc, and Clark-Hurth. Presently, NTN is operating in over 50 facilities globally and is the third largest bearing producer, in the world.