Low Speed Size Chart
Check your handpiece model below to find the correct bearing kit. All dimensions in mm (ID x OD x W).
| ISO Code | Dimensions (ID x OD x W) | Material / Shield | Common Application | View Part |
|---|---|---|---|---|
| MR74ZZ | 4.00 x 7.00 x 2.00/2.50 mm | Stainless / Metal Shield | Contra Angle Heads, Air Motors | View Details |
| MR126ZZ | 6.00 x 12.00 x 4.00 mm | Stainless / Metal Shield | Air Motors, Lab Handpieces | View Details |
| MR148ZZ | 8.00 x 14.00 x 4.00 mm | Stainless / Metal Shield | NSK Low Speed Motors | View Details |
| 683ZZ (Open/Shielded) | 3.00 x 7.00 x 2.00/3.00 mm | Stainless / Metal Shield | Latch Type Heads (RA) | View Details |
| 693ZZ | 3.00 x 8.00 x 3.00/4.00 mm | Stainless / Metal Shield | Prophy Angles, Straight HP | View Details |
| R2ZZ / R144 | 3.175 x 6.35 x 2.38 mm | Stainless / Metal Shield | American Low Speed Models | View Details |
← Scroll right to view more sizes
Built for High Torque & Heavy Loads
Focus on Material – Stainless Steel:
“Unlike high-speed turbines that require lightweight ceramic balls, low-speed contra angles and motors need toughness. Our bearings are manufactured from premium 440C Stainless Steel. This material provides the high load-bearing capacity needed for polishing, grinding, and implant procedures, while offering excellent resistance to corrosion during autoclave sterilization.”
Focus on Shielding – ZZ vs Open:
“Contamination is the #1 killer of low-speed bearings. Prophy paste and tooth dust can easily enter the gear mechanism. We utilize tight-fitting Metal Shields (ZZ) or Rubber Seals (2RS) to keep contaminants out and retain the grease inside. This significantly extends the service life of your contra-angle heads and air motor rotors.”
Our Products
Not sure which bearing fits your handpiece?
Don’t guess. Send us a photo of your turbine or the old bearing. Our technicians will identify the correct ISO part number for you within 1 hour.
FAQ for Low Speed Dental Bearings
Can I use high-speed ceramic bearings in a low-speed handpiece?
Generally, no. High-speed bearings (like SR144) utilize retainers designed for speed (400k RPM), not torque. Low-speed applications (20k-40k RPM) require deep-groove steel bearings with robust cages that can handle the axial load of latch-type burs. Using a high-speed bearing here may lead to premature failure under load.
Why do my low-speed bearings rust after autoclaving?
Even stainless steel can corrode if subjected to harsh chemicals or left wet. Our bearings use 440C Stainless Steel, which is highly resistant to oxidation. However, we strongly recommend lubricating the low-speed motor and attachment before and after sterilization to displace moisture and protect the raceways.
Do these bearings fit Dental Laboratory Handpieces (Marathon/Strong)?
Yes. Many dental lab micromotors (like Saeyang Marathon or Strong) use standard deep-groove ball bearings such as 1480, 1260, or 1040. Please check the dimensions of your specific lab handpiece or consult our Cross-Reference Table to find the correct match.
What is the difference between MR74 and MR126?
These are size codes. MR74ZZ (4x7x2.5mm) is typically used in the head of the contra-angle where space is tight. MR126ZZ (6x12x4mm) is larger and typically used in the air motor body to support the main drive shaft. You will often need both types to completely rebuild a low-speed set.