Deep groove ball bearing 638-8-ZZ-SKF

What does the suffix ... mean?
RS, 2RS, 2RSH, 2RS1, RSR, 2RSR, E, EE, LLU, LLB, DU, DDU
These suffixes mean "with 1 or 2 rubber seals". At 123Roulement, we use the number "2" to specify when the bearing is sealed on both sides.
C3, C4
Means "increased internal clearance". Often referred to as high-speed, this means that the bearing is designed for high rotational speeds and moderately high temperatures. CAUTION: a bearing with increased internal clearance will not operate optimally at low speeds. Please refer to the data sheet for the bearing you are looking for to find out its rotation speed limit.
ZZ, 2Z, ZR, Z
These suffixes mean "with 1 or 2 sheet metal deflectors", for dust-tightness. At 123Roulement, we specify whether the bearing is sealed on 2 sides with "ZZ".
TN9, TVH, TVP, G15
These suffixes indicate that the cage (the part of the bearing that holds the balls apart) is made of polymer material. Usually made of glass-fiber-reinforced polyamide.
ABEC
The ABEC standard is used to classify bearings according to their machining tolerance. This standard is regularly called into question because it does not include certain technologies that are important for guaranteeing proper operation, both in terms of efficiency and bearing life.
123Roulement therefore makes little use of this standard.
BHT / VT
This suffix indicates that the bearing is designed for very high operating temperatures. In general, the temperature is indicated after this suffix.
Beware, these bearings are not suitable for all applications, and will require a high temperature for optimum service life.
How do I know if my bearing is stainless steel?
A stainless steel bearing is generally magnetizable, as it is made from AISI 420 stainless steel, which is harder and more shock-resistant than standard stainless steel (AISI 304).
To check whether your bearing is made of stainless steel, simply read the reference engraved on the side of the bearing. This reference should begin with the prefix "S" meaning "Stainless Steel".
What's the difference between all the choices I have for my part number (e.g. 6205-2RS)?
Some bearings are available with more or less important variants (high or low internal clearance, special grease, very high temperature, etc.). These variants are systematically indicated by prefixes and suffixes in the part number.
For example, the suffix "2RS" means that the bearing is splash-proof, thanks to a sealing flange on both sides of the bearing.
The suffix "C3" means that the bearing has increased internal clearance, and will require a higher operating temperature, or a higher rotation speed.