Full complement cylindrical roller bearings, defined as cage-free constructions packing the maximum number of rollers into the cross-section, deliver a static and dynamic radial capacity gain of roughly 20% to 40% over a same-bore caged design, with the trade-off being a sharply reduced limiting speed and higher operating friction [S7].
The mechanism is straightforward: removing the cage removes the inter-roller spacing, so the same boundary dimensions can hold more rolling elements; the Schaeffler INA single-row full complement range (series SL1818, SL1829, SL1830, SL1822 and SL1923) and equivalents from SLF (NCF18..V, NCF29..V, NCF30..V) are built around this principle [S1][S3]. Where a caged cylindrical roller bearing will run at its catalogue limiting speed, the same bore in full complement geometry will typically be derated by a factor of three to five.
Where the 20% to 40% radial gain comes from
The radial load gain in a full complement cylindrical bearing is mechanical, not metallurgical: more rolling elements share the applied load, and the inner/outer ring geometry is unchanged, so each roller still carries line contact stress on the same raceway profile [S1]. Schaeffler documents the consequence as a basic dynamic load rating C<sub>r</sub> increase that, on its single-row full complement family, is the headline reason the series exists at all [S1]. The same principle shows up in full complement deep groove ball bearings: a 6203 caged deep groove ball bearing rated C = 9550 N and C<sub>0</sub> = 4800 N becomes a 6203 full complement rated C = 14000 N and C<sub>0</sub> = 7000 N, a 46% dynamic and 46% static gain, at the cost of the limiting speed collapsing from 17,100 r/min (grease) to 2,000 r/min [S2].
The capacity bonus is identical in concept for full complement tapered roller bearing variants and for needle roller complements, where the absence of a cage allows a near-solid sleeve of rollers to fill the radial space. Across families, vendors and engineering sources converge on the 20% to 40% radial-capacity uplift as a working figure for first-pass sizing [S7].
Speed derating: the cost you pay for the extra rollers
The same removal of the cage that adds load also removes the only thing separating adjacent rollers, so they slide against each other at the pitch-line velocity. That sliding is the dominant friction source and the dominant heat source, which is why catalogue limiting speeds for full complement cylindrical roller bearings sit at roughly 20% to 33% of the equivalent caged bearing's speed [S3][S5]. TFL Bearings' guide places the full complement family in slow, heavily loaded applications (crane sheaves, bucket wheels, excavator swing bearings, heavy-duty gearboxes) precisely because of this thermal ceiling [S5].
The 6203 example quantifies the gap: caged deep groove at 17,100 r/min (grease) versus full complement at 2,000 r/min (grease), an 8.5x derate [S2]. For a hot-end gearbox or any application expected to run above ~25% of the caged bearing's limiting speed, the full complement geometry will either overheat or demand an oil-flow rate the housing cannot supply. The Schaeffler INA documentation explicitly lists "very high radial loads at lower speeds" as the use case where the geometry wins [S1].
Design variants and their real-world fit
Within the single-row full complement family there are three sub-variants a buyer has to choose between, and the right pick depends on whether the bearing also has to locate the shaft axially. The NCF design (NCF18..V, NCF29..V, NCF30..V) carries axial force in one direction only, with a retaining ring on the outer ring that does not carry load [S2][S3]. The NJG design (heavy 23 series) is intended for highly loaded, low-speed service and is self-retaining, so the outer ring plus roller set stay together when the inner ring is removed, easing mount and dismount [S2]. Matched sets (suffix DR/TR/QR) bundle two, three or four bearings to a tight cross-section tolerance for even load sharing where a single bearing is too small for the load [S2].
For general industrial gearboxes and electric motors, a caged single-row cylindrical roller bearing (NU, NJ, NUP, N) is still the right default: separable, low friction, separable mounting, and the full limiting speed band of the housing [S5]. Full complement is the right pick for slow, heavy radial service such as rolling mill back-up rolls, crane sheaves, bucket-wheel excavators, and gearboxes where the pinion speed is below roughly 200 r/min and the radial load is the limiting design factor [S5]. Tapered roller applications follow the same logic: caged for speed and combined radial+axial loading, full complement where the radial component dominates and the speed is low.
Geometry, standards, and clearances to specify
Single-row full complement cylindrical roller bearings are dimensionally interchangeable with caged equivalents of the same bore: the boundary dimensions follow ISO 15, with DIN 616 and DIN 5412-1 as the older national references, and tolerances are held to PN (standard) per DIN 620-2 / ISO 492 [S3]. Radial clearance is supplied to CN as default per DIN 620-4 / ISO 5753-1, with C2, C3, C4 and special clearances available on request [S3]. Working temperature is set by the heat-treatment stabilisation: S0 to 150 °C for outer diameters up to 120 mm, S1 to 200 °C for larger sizes, with the lubricant usually the real ceiling, not the steel [S3].
Because the bearings ship without seals and without grease, the housing has to provide both, and the lubricant choice is the main speed lever. A full complement bearing run on oil bath or oil-mist can usually take 30% to 50% higher speed than the same bearing on grease, and a high-viscosity PAO or EP grease with a thickener rated to the S0/S1 limit closes the gap further [S3]. The rollers in the SL series are profile-end ground, with a slight lateral curvature at the roller tip, to suppress damaging edge stresses under the heavier line contact that the full complement geometry loads onto the raceway [S1].
Common failure modes if you specify the wrong one
Specify full complement where the duty cycle demands speed and you will see lubricant starvation, raceway glazing, and a rapid drop in C<sub>r</sub> well before the catalogue L10 life. The Schaeffler INA documentation is explicit on the cause: no cage means the rollers touch each other, the contact area is the rolling-element OD, and the resulting friction term dominates the heat balance at speed [S1]. SLF and downstream sources document the same mechanism, with the practical consequence that full complement bearings are usually the wrong pick for anything above roughly 1,000 r/min continuous unless the housing can supply forced oil at the rate the bearing needs to dump the extra heat [S3].
Specify caged where the radial load is the actual limit, and you will oversize the bearing to reach C<sub>r</sub>, paying for a larger bore, a larger housing, and a stiffer shaft than the duty actually needs. The 20% to 40% radial uplift of the full complement geometry is, in those cases, a real cost and weight saving, particularly on slow gearboxes where the bearing envelope is set by the bending moment on the shaft rather than the speed [S7]. The right answer is to derate the full complement bearing to its real operating speed in the L10 calculation rather than read its catalogue limiting speed as a hard wall, because grease starvation and oil flow limit the bearing long before its mechanical strength does.
Decision map: when to pick which
Use caged cylindrical (NU/NJ/NUP/N) as the default for gearboxes, electric motors, pumps, and any continuous duty above roughly 1,000 r/min where the radial load fits within the caged C<sub>r</sub> at the chosen bore [S5]. Use full complement (NCF, NJG, SL series) when the duty is slow (typically below ~600 r/min continuous), the radial load is the binding constraint, and the housing can supply adequate lubricant and cooling; expect a 20% to 40% radial uplift at the cost of a 3x to 8x speed derate [S1][S2][S5][S7]. Use full complement deep groove ball bearings only for narrow special cases where the duty is shock-loaded and intermittent, never for continuous high-speed shaft support, and always re-rate the limiting speed to the real operating point [S2].
Neither is on the public 2026-Q3 catalogue sheet, but both would shift the trade-off lines in this map.
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