6204 2RS Bearing: The 20x47x14 Workhorse Explained

The 6204-2RS is one of the most common mid-size deep groove ball bearings you'll find in motors, pumps, and gearboxes - at the 20mm shaft tier, it's the part quietly spinning inside countless small pumps and fractional-horsepower motors. The front of the part number, 6204, fixes the dimensions. The suffix, 2RS, tells you how it lives: double rubber seals, factory-greased, maintenance-free once installed. This article walks through the specs, load ratings, applications, and replacement details of the 6204 2RS bearing in one pass.
Dimensions first. The 6204 2RS bearing measures 20×47×14mm - 20mm bore, 47mm outside diameter, 14mm width - defined by ISO 15 and identical worldwide. Its place in the 6200 series is easy to picture: one step up from the 6203 (17×40×12), one step down from the 6205 (25×52×15). Measure the shaft and the housing bore, and you'll know in seconds whether this is the size you need.
Load rating is where selection actually happens. The 6204 2RS bearing carries a basic dynamic load rating Cr of about 13.5kN and a static rating C0r of about 6.55kN per the SKF specification table - other brands publish slightly different numbers, and that's normal. What does 13.5kN mean in practice? Under ordinary duty, it carries the rotor load of a several-kilowatt motor with plenty of margin. The rating isn't a peak value you can exceed occasionally; it's the load corresponding to a reference life of one million revolutions, so real selection derates it with service factors for the actual duty cycle.
Speed is next. The 6204 2RS bearing has a reference limiting speed around 10,000 rpm with grease lubrication, again per SKF's data. That's a reference, not a wall - the practical ceiling depends on clearance, grease, load, and how well the housing sheds heat. As operating speed approaches that line, the C3 clearance variant usually becomes the safer call, because thermal expansion needs room. If your machine runs above 10,000 rpm day in and day out, it's time to talk about open bearings with forced lubrication or a higher precision grade.
The 2RS sealing is exactly why this bearing is maintenance-free. Double rubber seals, typically NBR, keep dust and moisture out while trapping the factory grease inside - fit it and forget it. The trade-offs are slightly higher friction and a temperature ceiling: NBR seals are usually rated to about 100°C, and hot applications can step up to FKM fluoro-rubber seals rated near 150°C. Compare that with ZZ metal shields, which suit high-speed, low-contamination spots, or open bearings for externally lubricated systems. The 6204 2RS bearing belongs to the class of parts you install when you don't want to touch them again.
Clearance and precision finish the code. CN, the normal clearance, covers most jobs; motor builders often specify C3 instead, leaving room for heat at speed. Precision is P0 for general equipment, P6 for tighter machinery. These suffixes ride along in the same part number - so order a 6204 2RS bearing with the full designation written out, never just "6204".
Applications for this size are broad. BLH Bearing's automotive application reference lists the 6204-ZZ/2RS among its small deep groove ball bearings, and beyond vehicles the 6204 2RS bearing shows up in domestic and commercial pumps, small motors, gear reducers, power tools, agricultural machinery, and conveyor equipment. If the shaft is 20mm and the load is primarily radial, 6204 is usually the standard answer.
Interchangeability deserves one honest note. The 6204 is an ISO-standard size, so a 6204-2RS from SKF, NSK, FAG, or NTN fits the same seat - but dimensional interchangeability is not performance interchangeability. Load ratings, seal materials, noise, and service life differ between brands. When sourcing a replacement 6204 2RS bearing, verify three things: dimensions, the Cr rating, and the seal type, then buy from a channel that can prove what it ships.
On the supply side, BLH Bearing - Dongguan Lihao Bearing Co., Ltd - carries the 6204-ZZ/2RS in its 6200 series production, factory-direct with metric and imperial capability and OEM/ODM welcome. For volume buyers, sending the duty - speed, load, environment - to the factory engineer beats reordering from an old part number, because they can confirm whether CN or C3, NBR or FKM, P0 or P6 fits the machine that actually runs the bearing.
One line to remember: the 6204 2RS bearing is the 20×47×14 maintenance-free workhorse - the dimensions are fixed by ISO, but clearance, precision, and seal material are decisions you get to make. Don't let the suffix be the thing you forgot.