MR128ZZ EZO 8x12x3.5 mm - Miniature Deep Groove Ball Bearing

MR128ZZ EZO 8x12x3.5 mm - Miniature Deep Groove Ball Bearing

EZO MR128ZZ is a miniature deep groove ball bearing with dimensions 8x12x3.5 mm, fitted with metal shields on both sides. It belongs to the metric MR miniature bearing series. The ZZ suffix indicates metal shields on both sides, helping protect the bearing interior and retain lubricant while maintaining low running friction.

Technical data

EZO MR128ZZ dimensions

The basic dimensions are:

d: 8 mm
D: 12 mm
B: 3.5 mm

Complete dimensional specification:

8x12x3.5 mm

MR128ZZ has an extremely compact cross-section. With an 8 mm bore, the outside diameter is only 12 mm and the width is 3.5 mm, making it suitable for mechanisms where bearing installation space is severely restricted.

What does MR128ZZ mean?

The complete MR128ZZ designation identifies a specific miniature EZO bearing.

MR - metric miniature deep groove ball bearing series.

128 - size designation corresponding to dimensions 8x12x3.5 mm.

ZZ - metal shields on both sides.

The complete designation should be used when selecting or ordering the bearing because an 8 mm bore alone is not sufficient to identify the correct product.

EZO MR128ZZ construction

MR128ZZ is a single-row miniature deep groove ball bearing. Its basic construction consists of:

• inner ring,
• outer ring,
• balls,
• cage,
• two metal shields.

The bearing is designed primarily to accommodate radial loads. Its deep groove raceway geometry also enables it to accommodate axial loads within the operating limits of the specific bearing arrangement.

What does ZZ mean?

The ZZ suffix indicates metal shields on both sides of the bearing.

The shields help to:

• reduce the ingress of contaminants,
• protect the raceways and rolling elements,
• retain lubricant inside the bearing,
• maintain low running friction.

ZZ metal shields should not be confused with elastomer seals such as 2RS.

MR128ZZ vs MR128

Both versions have the same basic bearing size:

8x12x3.5 mm

MR128ZZ - version with metal shields on both sides.

MR128 - basic open version without ZZ shields.

The correct version should be selected according to operating conditions, contamination protection requirements and the design of the mechanism.

MR128ZZ vs SMR128ZZ

The designations MR128ZZ and SMR128ZZ are similar and share the same basic dimensions of 8x12x3.5 mm, but they should not be treated as identical products.

MR128ZZ - standard MR series.

SMR128ZZ - stainless steel SMR series from EZO.

If stainless steel construction is required, the correctly designated SMR128ZZ version should be selected rather than assuming that standard MR128ZZ has the same material specification.

Compact 8x12x3.5 mm cross-section

EZO MR128ZZ combines:

• 8 mm bore,
• 12 mm outside diameter,
• 3.5 mm width.

The difference between the bore and outside diameter is only 4 mm, providing an exceptionally small radial cross-section.

This compact geometry makes the bearing suitable for precision mechanisms where available installation space is very limited.

Selection and interchangeability

When selecting EZO MR128ZZ, verify:

• complete MR128ZZ designation,
• 8 mm bore diameter,
• 12 mm outside diameter,
• 3.5 mm width,
• ZZ metal shields,
• required load capacity,
• operating speed,
• environmental conditions,
• lubrication requirements,
• shaft and housing tolerances.

Matching dimensions of 8x12x3.5 mm alone do not confirm complete technical interchangeability.

Applications

EZO MR128ZZ is intended for compact and precision mechanisms requiring a miniature deep groove ball bearing with a very small cross-section.

Suitability for a specific application should be determined according to actual loads, operating speed, environmental conditions and the design requirements of the complete bearing arrangement.

Installation

Due to its miniature dimensions and small cross-section, MR128ZZ should be handled carefully during installation.

When fitting the bearing onto a shaft, mounting force should be applied to the inner ring. When pressing it into a housing, force should be applied to the outer ring.

Mounting force should not be transmitted through the balls, and direct pressure on the ZZ metal shields should be avoided.

Alternative designations and search references

• EZO MR128ZZ
• MR128ZZ EZO
• MR 128 ZZ EZO
• EZO MR 128 ZZ
• MR128ZZ 8x12x3.5
• EZO MR128ZZ 8x12x3.5
• MR 128 ZZ 8x12x3.5
• MR128 bearing
• miniature bearing 8x12x3.5
• deep groove ball bearing 8x12x3.5

FAQ - EZO MR128ZZ

What are the dimensions of EZO MR128ZZ?

The bearing measures 8x12x3.5 mm, with an 8 mm bore, 12 mm outside diameter and 3.5 mm width.

What type of bearing is MR128ZZ?

It is a single-row miniature deep groove ball bearing.

What does MR mean?

MR identifies a metric miniature deep groove ball bearing series.

What does ZZ mean?

ZZ indicates metal shields on both sides of the bearing.

Is MR128ZZ an open bearing?

No. It is fitted with metal shields on both sides.

Are MR128ZZ and SMR128ZZ the same bearing?

No. They share the same basic dimensions of 8x12x3.5 mm, but SMR128ZZ is the stainless steel EZO version. The complete designation should therefore be checked when selecting a replacement.

Can any 8x12x3.5 mm bearing replace EZO MR128ZZ?

Not automatically. Bearing design, closure type, material version and required operating characteristics should also be verified.

EZO MR128ZZ - key information

EZO MR128ZZ 8x12x3.5 mm is a miniature metric deep groove ball bearing with ZZ metal shields on both sides. Its 8 mm bore, 12 mm outside diameter and 3.5 mm width provide an exceptionally compact bearing cross-section. MR128ZZ should be distinguished from the stainless steel SMR128ZZ version.

Available from simmering.pl, a specialist supplier of bearings and industrial components. Stock in Poland with worldwide shipping.