In a cylindrical roller bearing (CRB), the rollers sit between the inner and outer raceways and carry radial load. How many rollers you can fit, and how you keep them apart, decides almost the entire behaviour of the bearing. Remove the cage and you can pack in the maximum number of rollers. That one change trades speed for load in a way that is easy to predict and easy to specify.
1. What is an RSL full-complement bearing
An RSL bearing is a single-row, full-complement (cage-free) cylindrical roller bearing. The space between the bore and the outer ring is filled with the largest possible count of rollers, and there is no cage (separator) holding them apart. Because every millimetre of space is occupied by a roller:
- Highest radial load capacity — for a given bore and outside diameter, it carries more radial load than any caged equivalent.
- Very high stiffness — elastic deflection under load is minimal.
- Compact radial section — more rollers in the same envelope save axial mounting space.
- The cost: without a cage, adjacent rollers touch and slide as they pass through the load zone, creating heat. So the allowable speed is far lower than a caged bearing of the same size.
2. RSL vs. caged cylindrical roller bearings
A caged CRB uses a separator to space and guide each roller. It fits fewer rollers than the full-complement type, but every roller runs in its own pocket:
- Lower friction, higher allowable speed — rollers do not collide.
- Better for high speed — spindles, gearboxes and electric motors.
- Lower radial capacity than the same-size full-complement type (fewer rollers share the load).
| Factor | RSL full-complement | Caged (separator) |
|---|---|---|
| Radial load (same size) | Highest | Lower (fewer rollers) |
| Axial load | None (radial only)* | None, except limited in NJ/NUP* |
| Allowable speed | Low (about 30-50% of caged) | High |
| Stiffness | Very high | High |
| Radial section / envelope | Smaller (space-saving) | Larger |
| Heat at speed | Higher (rollers rub) | Lower |
| Typical duty | Slow, heavy, shock | Fast, steady |
*A cylindrical roller bearing is fundamentally radial. For combined radial + axial load, use a locating variant (NJ/NUP, limited axial) or switch type (tapered, spherical, angular-contact).
3. RSL vs. NNF double-row full-complement
Both are full-complement, but they are not the same bearing. RSL is single-row; NNF is double-row.
The double-row NNF is common in wind-gearbox and planetary-reduction duty, where stiffness and shock resistance matter more than speed. The single-row RSL is the lighter option for simpler heavy-radial positions such asæ…¢-turning shafts, rollers and low-speed gearbox supports. For a deeper look at the double-row design, see our NNF guide.
4. Where RSL bearings earn their keep
Good fits: crushers, ball mills, rolling stands, hoists, conveyors, winches, heavy/low-speed gearboxes, slewing supports and port machinery, plus some slow fan shafts. Slow, heavy, shock is the RSL's home ground. For the cage-vs-full-complement trade-off in full, see the comparison guide.
5. How to select an RSL bearing (checklist)
- Load: define radial load — both dynamic (running) and static. For crusher/shock duty apply an impact factor (often 1.5-2.5×).
- Speed: calculate actual rpm. The full-complement type is viable only below roughly 40-50% of a caged bearing's limiting speed.
- Envelope: measure shaft diameter (bore) and available radial space. The smaller section is an advantage in tight housings.
- Locating vs. non-locating: choose the series — N/NU (non-locating, free axially), NJ/NUP (limited axial location) or full-complement RSL/NCF/NJG.
- Accuracy & clearance: specify P0/P6 and the right internal clearance for your temperature and fit.
- Lubrication: at low speed the full-complement type needs ample grease (or oil bath); confirm the housing supports it.
6. Mounting & lubrication notes
- Fit: use an interference fit on the rotating ring; the stationary ring should be a sliding fit so the bearing can self-align radially.
- Alignment: full-complement rows are unforgiving of misalignment — keep shafts and housings within the bearing's tolerance.
- Lubrication: fill to the recommended grease volume; do not over-pack, which traps heat. Re-grease on the machine's schedule.
- Speed discipline: the limiting speed printed for the caged type does not apply — stay within the full-complement limit or the rollers will overheat.
7. RAYSDE RSL product line
The full-complement cylindrical roller bearing is the series we are asked about most and know best — we would rather engineer around your drawing than flip through a catalogue. Standard sizes: minimum order 300 sets, lead time 15-20 days; non-standard: minimum order 50 sets, 30-45 days. Full specifications are on the full-complement landing page. RAYSDE supplies these as a Supplier & OEM.
8. Frequently asked questions
What does RSL mean in a cylindrical roller bearing code?
RSL denotes a single-row, full-complement (cage-free) cylindrical roller bearing. The rollers are packed to the maximum count the bore and outer ring allow, with no cage separating them. Exact boundary dimensions and capacity depend on the specific size and series and should be confirmed against the product page or a quotation.
Can an RSL bearing take axial load?
No. A full-complement cylindrical roller bearing is a radial bearing; it carries radial load only. For light axial location use a locating variant such as NJ/NUP, or move to a type that handles combined load (tapered, spherical, or angular-contact) when axial force is significant.
Why is the allowable speed lower than a caged bearing?
Without a cage, adjacent rollers touch and slide as they pass through the load zone, generating extra friction and heat. A caged bearing keeps each roller in its own pocket, so it runs cooler and can be turned much faster. If your machine runs below roughly 40-50% of a caged bearing's limiting speed, the full-complement design usually pays off.
How is an RSL different from an NNF double-row full-complement bearing?
RSL is single-row; NNF is double-row. The double-row packs two roller sets for even higher radial stiffness and load in a compact axial envelope, common in wind-gearbox and planetary-reduction duty. RSL is the lighter, single-row option for straightforward heavy-radial, low-speed positions. Pick by space, load direction, and stiffness need; exact figures come from the product page or a quotation.
Do you supply RSL bearings as a Supplier & OEM?
Yes. RAYSDE supplies RSL and other full-complement cylindrical roller bearings as a Supplier & OEM. Standard and customized designs are available; exact dimensions, load ratings and price are provided on request through the product page or a direct inquiry.
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