Neither is inherently better; it depends entirely on your application. Ball bearings can be either "open" (unsealed) or "sealed." Sealed bearings are best for dirty, wet environments and low-maintenance needs, while open/shielded ball bearings are better for high-speed, precision applications needing low friction.
While sealed bearings excel at keeping out dirt and moisture, their main drawbacks are higher rotational friction, slower speed limits, heat generation, and the inability to be easily re-lubricated once the factory grease breaks down.
Top Bearing Manufacturers Ranked
Even so, average bearing life can range from 80,000 to 120,000 miles depending on how a vehicle is driven and what the bearings are exposed to. Wheel bearing cartridges and hubs are sealed and lubed for life so no maintenance is required.
Hub seals are critical for preventing lubricant leaks and keeping contaminants like dirt and water out of the wheel bearings. A failed seal can lead to seized wheel bearings, which can cause a wheel to come apart while driving, leading to an accident and extensive damage.
The sealed bearing does not require relubrication, while the external seal is only occasionally relubricated. In practice, this means that use of grease is reduced to a few tonnes per year.
Humming: A humming noise while driving can be caused by several issues, but a wheel bearing or CV joint is one of the more likely (and problematic) issues. Squealing & Growling: The classic sounds of a bad wheel bearing are cyclic chirping, squealing, and growling noises.
Spraying WD40 will remove the old grease, but it won't clean your bearings, and it won't regrase them afterwards. Filling your bearings with WD40 and skating them without regreasing will result in destroyed bearings.
Very gently remove the rubber seals by prising out the seal from the inner lip. You can use a penknife or small screwdriver but do not push it too far into the bearing or you may damage the retainer (cage). Use a degreaser and some paper cloth to make sure you fully clean away all old grease before relubricating.
Design Considerations for Plain Bearings
The 2:1 Bearing Ratio is officially defined as the maximum ratio of moment arm distance to bearing length which will not cause binding or prevent motion. The Binding Ratio is often displayed numerically as “2:1,” where “2” is the moment arm distance and “1” is bearing length.
1. SKF:Svenska Kullager-Fabriken (Sweden) SKF is the world's largest bearing manufacturer, founded in Gothenburg, Sweden, in 1907.
Timken bearings are widely considered a premium, industry-leading choice. They are renowned for their strict quality control, proprietary steel, and precision heat-treating, which result in exceptional durability and tighter tolerances. While they come at a higher price, they consistently outperform cheaper, generic alternatives.
The best ball bearing brands depend highly on your specific application. For industrial, automotive, and heavy-duty use, premium global manufacturers like SKF, NSK, and Timken are the gold standards for precision and durability. For niche or specialized hobbies, specific leaders dominate the market.
Skill 1: Bearings – 3 Rules
Problems with lubrication are the major cause of premature bearing wear and failure, but it's not just an issue of insufficient lubrication. Over or under filling can also cause problems, as can using an incorrect or incompatible lubricant or mixing products inappropriately.
A: Use a sealed bearing when your environment is dirty, dusty, or exposed to moisture, or if you want a maintenance-free solution (no re-lubrication). In contrast, use a shielded bearing in relatively clean, dry conditions or high-speed applications where low friction is more important than maximum sealing.
The 6203 is a 17 mm Ball Bearing that can be used in many rotary and factory automation applications. The 6203 Deep Groove Ball Bearings is an open style bearing. The 6203Z ball bearing is a single row raceway and single shielded. The 6203ZZ ball bearing has a single row raceway and it is shielded on each side.
Common ball bearing sizes are dictated by standardized ISO and ABEC metrics, focusing on Inner Diameter (ID), Outer Diameter (OD), and Width. These numbers dictate both industrial machines and everyday consumer goods.
0031” max.). For normal passenger car application,. 0031” of bearing clearance would generally be too much. However, if we take the same engine, let's say a small V-8, and put it in a truck used to pull a camping trailer and use a heavier weight oil, the larger clearance would be more acceptable.
For standard steel sealed bearings, a high-quality Lithium Complex or Polyurea grease with a low-to-medium viscosity is best. These provide excellent moisture resistance and long-term durability. If you are servicing ceramic bearings, use a dedicated ceramic grease (like Kluber Isoflex NB-52) to prevent the balls from sliding instead of rolling.
Yes, you can clean bearings (such as those for skateboards, roller skates, or fidget spinners) with isopropyl alcohol. It is a highly recommended solvent because it effectively breaks down old grease, removes grime, and dries without leaving a residue.
Mistake #2: Over-Greasing or Under-Greasing
Under-greasing causes metal-on-metal contact, while over-greasing can rupture seals and draw dust. Your bearing size and operating environment determine the ideal balance.
The best bearing cleaners depend on your setup, but the ultimate industry standard is a dedicated unit like the Bones Bearings Cleaning Unit paired with a heavy-duty solvent like pure acetone or 95% isopropyl alcohol. For a fast, all-in-one approach, electric or mechanical scrubbers and citrus-based washes are top-tier choices.
WD-40 White Lithium Grease is a great lubricant for bearings.
What Should You Avoid When Cleaning Bearings?