V-groove and U-groove guide bearings, wire straightener rollers, and precision guide rollers purpose-built for tire radial (cord) production lines. NLHB manufactures a full range of V-slot and U-slot specialized bearings that combine precise groove-angle control, outstanding wear resistance, and an extended service life — the benchmark components for modern tire and rubber calendering equipment.
What Is a V-Groove / U-Groove Tire Radial Line Bearing?
In a tire radial line, steel or textile cord must be guided, straightened, and tensioned with micron-level repeatability before it is calendered into the rubber sheet. The small bearings that run inside the straightening rollers and guide pulleys are V-groove (angled, typically 90°, 100° or 120°) or U-groove (radius-bottom) bearings. Their job is to keep the cord tracking true, absorb high line speed and side-load, and resist the abrasive rubber dust and continuous vibration of a tire plant. NLHB supplies these bearings as direct, dimension-for-dimension replacements for the OEM reference numbers used on VMI, Mesnac, Safeland, and similar tire-building and calendering machines.
V-Groove vs U-Groove: Which Do You Need?
| Feature | V-Groove Bearing | U-Groove Bearing |
|---|---|---|
| Groove profile | Two angled flanks meeting at a point (90° / 100° / 120°) | Single radius (R) bottom, e.g. R1, R1.25, R2, R0.8 |
| Typical role | Cord / wire alignment and angular guidance | Wire straightening, smooth radius tracking |
| Tracking precision | Very high — angular flanks self-center the cord | High — radius bottom protects delicate cord coating |
| Common reference | 608-ZZ V90°, 624-ZZ V90°, 634X2-ZZ V100° | 608-ZZ U (R1 / R2), 634X2-ZZ U (R1.25) |
As a rule of thumb, choose V-groove bearings where the cord must be held to a precise angle under side-load, and U-groove bearings where the cord runs over a defined radius and you want to avoid nicking or flattening it. Many straightening cassettes mix the two types in the same block — that is why NLHB offers both families in matching 4 mm, 8 mm and 10 mm bore sizes.
Key Features
- Precise groove angles. Every V-groove is ground to the nominal 90°, 100° or 120° called up on the OEM drawing, ensuring perfect alignment of the cord at the calender nip.
- Excellent wear resistance. Races and grooves are produced from high-purity bearing steel with a specialized heat-treatment process that resists the abrasive rubber-dust and continuous-fretting environment of a tire plant.
- Extended service life. Each bearing is 100% dimensionally and noise-inspected before shipment, so it holds its running accuracy over long maintenance intervals on the line.
- Drop-in OEM replacement. NLHB reference numbers map one-to-one to the OEM part numbers used on the cord straightener and guide-roller stations.
Technical Specifications
The complete NLHB range for tire radial lines is listed below. Dimensions are given as bore × outer diameter × width in millimetres; the U-groove radius R is in millimetres.
| NLHB No. | Drawing Group | OEM Reference | Dimensions (mm) | Cross-Reference Model | U-Groove Radius R (mm) |
|---|---|---|---|---|---|
| 1 | Six-in-one drawing | 30.M.13.236-00 | 8×22×7 | 608-ZZ V90° | — |
| 2 | Six-in-one drawing | 30.M.13.236-01 | 10×30×8 | 6000/30-ZZ V90° | |
| 3 | Six-in-one drawing | 30.M.13.236-02 | 10×30×14 | 62200-2RS V90° | |
| 13 | Six-in-one drawing | 30.M.13.236-05 | 8×22×7 | 608-ZZ U | 1 |
| 14 | Six-in-one drawing | 30.M.13.236-06 | 8×22×7 | 608-ZZ U | 2 |
| 4 | Fifteen-in-one drawing | 30.M.14.078-00 | 4×13×5 | 624-ZZ V90° | — |
| 5 | Fifteen-in-one drawing | 30.M.14.078-01 | 4×13×5 | 624-ZZ V90° | |
| 6 | Fifteen-in-one drawing | 30.M.14.078-02 | 4×16×5 | 634X2-ZZ V90° | |
| 15 | Fifteen-in-one drawing | 30.M.14.078-04 | 4×16×5 | 634X2-ZZ U | 1.25 |
| 7 | Fifteen-in-one drawing | 30.M.14.078-07 | 4×16×5 | 634X2-ZZ V100° | — |
| 8 | Fifteen-in-one drawing | 30.M.14.078-08 | 4×16×5 | 634X2-ZZ V90° | |
| 9 | Fifteen-in-one drawing | 30.M.14.078-12 | 8×22×7 | 608-ZZ V90° | |
| 10 | Fifteen-in-one drawing | 30.M.14.078-15 | 8×22×7 | 608-ZZ V120° | |
| 16 | Standalone drawing | 420-M.294.011/1 | 4×13×5 | 624-ZZ elliptical 100° | 0.8 |
| 11 | Three-in-one drawing | 420-M.294.012/1-01 | 4×16×5 | 634X2-ZZ V100° | — |
| 12 | Two-in-one drawing | 420-M.294.019/1 | 8×22×7 | 608-ZZ V120° |
Selection Guide
- Match the bore first. The bearing bore (4 mm, 8 mm or 10 mm) is set by the straightener-roller shaft in your cassette — this dimension cannot be improvised.
- Match the OEM drawing reference. Use the 30.M.13.236 / 30.M.14.078 / 420-M.294.xxx numbers above to identify the exact station, then pick the corresponding NLHB part.
- Confirm the groove geometry. Read the drawing for V-angle (90°/100°/120°) or U-radius (R0.8 / R1 / R1.25 / R2). A wrong groove angle will mis-track the cord and cause coating defects downstream.
- Choose the seal. -ZZ (metal shield) is standard for the dry, high-speed cord stations; -2RS (contact seal) is preferred where rubber dust or moisture ingress is heavy.
Typical Applications
- Tire radial production lines — steel and textile cord guiding, straightening and tensioning on calender and tire-building machines.
- Rubber calendering lines — fabric and cord let-off and wind-up guide rollers.
- Wire and cable straighteners — U-groove bearings for wire straightener rollers and wire-drawing guide pulleys.
- Conveyor and tracking rollers on rubber-processing and tire-curing auxiliary equipment.
Cross-Reference & Interchangeability
The NLHB V-groove and U-groove bearings in the table above are dimensionally built on standard miniature and thin-section bearing envelopes, so they can be cross-referenced to the catalogues of the major global bearing brands. Use the base envelope number to confirm fitment:
- 608 envelope (8×22×7) — interchangeable with SKF 608-2RS1, NSK 608DD, NTN 608LLB, FAG 608.2RSR and INA 608 base bearings; NLHB applies the V90° / V120° / U-groove modification.
- 6000/30 envelope (10×30×8/9) — cross-references to NSK 6300, NTN 6300, SKF 6300-2RS1 envelopes before grooving.
- 62200 envelope (10×30×14) — thin-section envelope comparable to SKF W 62200 / INA 62200 series wide miniature bearings.
- 624 / 634X2 envelope (4 mm bore) — matches NSK 624, NTN 624, FAG 624 and the wider 634-type envelopes for the 4×16×5 stations.
Note: the groove angle (V90°/V100°/V120°) and the U-groove radius are NLHB custom modifications; the brand-name equivalents listed above refer to the ungrooved base envelope only. Always order by the NLHB reference number to guarantee the correct groove geometry.
Installation
- Press the bearing onto the straightener-roller shaft with the groove facing the cord path; an inverted groove will reverse the tracking angle.
- Use a calibrated arbor press or induction heater — never strike the bearing with a hammer, as the hardened groove edges will chip.
- After installation, rotate the roller by hand and confirm the groove runs concentric to the cord line; re-shim if run-out exceeds 0.02 mm.
- Re-grease or replace on the cord-straightener maintenance schedule; early noise or groove polishing is the first sign that the bearing should be swapped before it affects cord quality.
FAQ
1. Are NLHB V-groove / U-groove bearings true replacements for the OEM parts on my tire line?
Yes. They are manufactured to the same envelope dimensions and groove geometry as the OEM reference numbers in the table (30.M.13.236, 30.M.14.078, 420-M.294.xxx series), so they drop straight into the existing cord-straightener and guide-roller stations.
2. Can I use a standard 608-ZZ bearing instead of the grooved version?
No. A standard 608 has a flat outer race and cannot guide the cord. The V90° / V120° / U-groove geometry is what controls cord tracking — only a purpose-grooved bearing will do the job.
3. What groove angle do I need — 90°, 100° or 120°?
The angle is dictated by the OEM drawing of the specific station. 90° is the most common for general cord guiding, 120° is used where the cord wraps a larger angle, and 100° appears on selected 634X2-size stations. Always order by drawing reference number.
4. Do you supply samples and small-batch quantities?
Yes. NLHB supports sample orders for line qualification and small-batch production runs — contact us with the NLHB reference number or the OEM part number from the table above.