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634-ZZ Mini Ball Bearing 4x16x5 Shielded R1640ZZ

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634-ZZ Mini Ball Bearing

Key Features

634-ZZ is a Miniature Ball Bearing manufactured to be Metal Shielded on both sides and is pre-lubricated with grease allowing it to be ready for use upon delivery. Made from Chrome Steel, 634-ZZ is a 630 Series miniature ball bearing meant for light-duty applications but despite its lightweight, can support moderate radial loads. Our 630 Series Mini Ball Bearings have a Larger Outer Diameter to be used in High Speed & Larger Load Capacity Applications.

Match Numbers / Interchange Numbers

MR634-ZZ, 634.2ZJ1, 634ZZ, 634-2Z, L-1640ZZ, R1640ZZ 

Applications / Industries

634-ZZ Miniature ball bearings are widely used in various industries and everyday applications such as Electric Fans, Automotives, RC Cars, RC Planes, RC Helicopters, Wipers, Throttles, Industrial & Medical Hand Pieces, Household Electrical Appliances, Medical Equipment, Robotics, Pulmonary Assist Devices, Cryogenic Coolers, Flow Meters, Fuel Control, Gyros, Syncros, Servos, and many more.

What are Miniature Ball Bearings?

A Miniature ball bearing is a type of small rolling-element bearing that uses roller balls to separate two “races,” or bearing rings. The key difference between these bearings and many others would be their small size, allowing them to be applied in smaller and tighter lightweight applications. The combination of the roller balls and bearing rings help to reduce surface contact and rotational friction across moving planes to accommodate axial loads.

Miniature Ball bearings help to facilitate motion by distributing loads and reducing friction for applications that have a high-speed requirement, ultimately aiding in extending the working life of your equipment while also effectively saving space in tight applications.

What are Rolling-Element Bearings?

Rolling-element bearings, commonly called rolling bearings, are bearings that carry a load by utilizing “rolling elements” between two concentric, grooved rings called races. The motion of the bearing races allows for the rolling elements to move with very little resistance and with little slide variance.

Some common types of rolling elements include ball, cylindrical, spherical, barrel, needle, spindle, or tapered.

What is the Difference Between Open, Shielded, and Sealed Rolling Bearings? 

The main difference between open and sealed/ shielded bearings is the application of lubrication. The main difference between sealed and shielded bearings is the presence of a protective enclosure.

  • Sealed and shielded bearings are lubricated with grease in the bearing factory. However, a rubber sealed bearing protects the bearing by using a seal that contacts the inner and outer race. This provides superior protection at the cost of operating speed and temperature.
  • Open bearings are meant to be lubricated with light oil, with periodic reapplication of lubrication, based on use.
  • Shielded rolling bearings contain an enclosure that helps to protect the working parts of the bearing from environmental debris that may be introduced and would otherwise reduce the ball bearing speed and lifespan. This metal shield is stamped onto the bearing and only contacts the outer ring, this allows for protection without sacrificing operating speed or temperature.
Online Catalog:
Dimensions & Material
Inner Diameter:
Outer Diameter:
Chevron SRI-2 Grease
Chrome Steel SAE-52100
ID: 4mm x OD: 16mm x W: 5mm
Product Details
Closure Type:
ZZ Metal Shielded on Both Sides
Grease RPM Limit:
Oil RPM Limit :
Static Load Rating:
117 lbf
Dynamic Load Rating:
302 lbf
Interchange Numbers:
MR634-ZZ, 634.2ZJ1, 634ZZ, 634-2Z, L-1640ZZ, R1640ZZ
634-ZZ Mini Ball Bearing 4x16x5 Shielded R1640ZZ

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