MRC203SZZ1Deep Groove Ball Bearing 17x40x12 mm, Two Contact Rubber Seals, 6203-2RS Envelope, 9,560 N Dynamic Rating

Product Description

What this part is

An MRC 203SZZ1 single-row deep groove ball bearing — 17 mm bore, 40 mm outside diameter, 12 mm width — with contact rubber seals on both faces. It arrives grease filled and sealed for life, so it is fitted and run without an external lubrication supply. This is the 6203 envelope, one of the most widely used small bearing sizes in industrial equipment.

Decoding the designation

203S – MRC single-row deep groove ball bearing, 17 mm bore; the same envelope as the ISO 6203
ZZ – in the MRC scheme this means two contact RUBBER seals, not shields. The MRC reading is the opposite of the NSK, SKF and FAG convention, where ZZ denotes steel shields
Trailing 1 – MRC internal variant code
No clearance suffix, so internal clearance is normal (CN / C0)
No snap ring groove and no snap ring

What these specs mean in practice

Contact rubber seals rub lightly on the inner ring land. That keeps water, dust and washdown spray out far more effectively than a non-contact steel shield, at the cost of a little running torque and a lower top speed. On a dirty or damp machine the seal is what determines bearing life, which is why the sealed version outlasts an open or shielded one in the same position. The 9,560 N dynamic rating governs fatigue life under rotating load; the 4,750 N static rating governs permissible load when the shaft is stopped or shock loaded.

Published ratings and mounting data

Bore: 17 mm (0.6693 in)
Outside diameter: 40 mm (1.5748 in)
Width: 12 mm (0.4724 in)
Rows: 1
Closure: two contact rubber seals
Dynamic load rating (Cr): 9,560 N
Static load rating (C0r): 4,750 N
Internal clearance: CN / C0 (normal)
Snap ring: not fitted
Lubrication: grease filled, sealed for life

Quantity and configuration

Sold as 1 Pc, a single complete bearing sealed on both faces. No snap ring, spacer or lock washer is included.

Fitting notes

Mounting force is applied to the ring being fitted so that no load passes through the balls. The seals are not a press surface. The bearing needs no grease charge on installation and no relubrication path in the housing.

Interchange guidance

The direct equivalent is a 6203-2RS class bearing from another maker in the 17 x 40 x 12 mm envelope with two contact seals: SKF 6203-2RSH, FAG 6203-2RSR, NSK 6203DDU, NTN 6203LLU, Koyo 6203-2RS, Timken 6203-2RS. Legacy metric-scheme numbers 87503 and 8503 refer to the same sealed 6203 size. A 6203ZZ or 6203-2Z with steel shields shares the envelope but is non-contact and less well sealed, so it is a related version rather than an equivalent. An open 6203 or MRC 203S is likewise not a substitute where sealing matters.