Deep Groove Ball Bearings

What it is

A deep groove ball bearing has an inner ring, an outer ring, a single row of balls and a cage. The raceway grooves are deep enough that the bearing carries radial load and a moderate thrust load in both directions. It runs at high speed with low friction. Boundary dimensions (bore, outside diameter and width) are standardized in ISO 15, with the matching American standard in ABMA 20, so a 6205 from any maker has the same dimensions. Closures, clearance and cage are suffix options.

How to identify

The basic number starts with 6. The next digit is the dimension series: 60xx extra light, 62xx light, 63xx medium, 64xx heavy. Thin-section series include 618xx, 619xx and 160xx. The last two digits are the bore code. Codes 00 to 03 mean 10, 12, 15 and 17 mm. From 04 up, multiply by 5 to get the bore in mm. Miniature sizes such as 608 use the last digit as the bore in mm.

Common sizes: bore x OD x width (mm)

The 608 miniature bearing used in skates and small tools is 8 x 22 x 7 mm.

Key points

• For the same bore, the 60, 62 and 63 series get larger in OD and width and carry more load. Do not swap series without checking the housing and the application.
• Load and speed ratings come from the maker's catalog. They vary by brand, cage and closure.
• Inch deep groove bearings (R-series, 1600 series and others) have their own numbering and are not covered by the metric bore code.
• Ask for the full number with suffixes. 6205-2RS C3 and 6205 open are the same size but not the same bearing.
• If the number is worn off, measure bore, OD and width in millimeters and match to the table.

Common mistakes

• Reading the bore code as millimeters (6204 is 20 mm, not 4 mm).
• Replacing a 63xx with a 62xx because the bore matched.
• Ignoring a snap-ring groove (N or NR suffix) on the outer ring.
• Fitting an open bearing where the original was sealed and lubricated for life.

Governing standards: ISO 15 (radial bearing boundary dimensions); ABMA 20 (radial bearings of ball, cylindrical roller and spherical roller types, metric design). Manufacturer catalogs for ratings.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.