SKF6018-ZDeep Groove Ball Bearing 90 x 140 x 24 mm, Single Steel Shield One Side, Normal Clearance, 1 Pc

Product Description

What this part is

A single-row deep groove ball bearing, 90 mm bore by 140 mm outside diameter by 24 mm wide, with a pressed steel shield on one side and the other side left open. Deep groove ball bearings carry radial load plus axial load in either direction. The one-shield form exists for a specific reason: it lets lubricant reach the bearing from the open face while the shield closes off the side facing the dirty end of the machine.

Decoding the designation

6 – single-row deep groove ball bearing0 – dimension series 60, the light section for this bore18 – bore code, 18 x 5 = 90 mm boreZ – a single pressed steel shield, on ONE side only. Two shields would be 2Z; contact rubber seals both sides would be 2RS1No clearance suffix – normal (CN) radial internal clearance

What these specs mean in practice

The single shield is the whole point of this part number, and it is where substitutions go wrong. A 6018-Z is not interchangeable with a 6018-2Z: the open face means the bearing depends on the housing to hold grease or supply oil on that side, and it will not retain a factory grease fill on its own the way a double-shielded bearing does. Fit a 6018-2Z where a 6018-Z belongs and you cut the bearing off from the gearbox oil that was feeding it. Fit a 6018-Z where a 6018-2Z belongs and the open face admits whatever the housing lets in.

Mount it with the shielded face toward the contamination — the seal, the coupling, the open end of the housing — and the open face toward the lubricant supply. Note too that a shield is not a seal: it runs with a small gap at the inner ring, costs almost no friction and does not limit speed, but it only holds back dry dust and coarse debris, not water or coolant.

Clearance is normal (CN), which suits a shaft and housing at similar temperatures with a standard interference fit. If the original was a C3, fit a C3.

Published specifications

Bore: 90 mmOutside diameter: 140 mmWidth: 24 mmRows: 1Closure: one pressed steel shield, one side open (Z)Internal clearance: normal (CN)Material: through-hardened bearing steelEAN: 7316576621093

Quantity and configuration

Sold as 1 piece. One shield fitted, one face open — that is the design, not a missing part. No snap ring, no housing.

Fitting notes

Check orientation before pressing: shield toward the dirt, open face toward the lubricant. Press or heat-mount on the inner ring only and never let force cross the balls, or the shield will be knocked out of true and rub. At 90 mm bore, heat mounting to about 80 to 100 °C is the easier route.

Interchange guidance

Genuine interchanges are same-envelope single-shielded bearings: FAG 6018-Z, NSK 6018Z, NTN 6018Z and Koyo 6018Z. A 6018-2Z (two shields), a 6018-2RS1 (contact seals both sides), a plain open 6018 and a 6018/C3 (greater clearance) are all related parts that change lubrication, sealing or fit-up — none of them is a drop-in equivalent.