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Precision outer bearing for rear wheel hub applications – The OEM 33115 Outer Bearing (Rear Hub) is a single‑row tapered roller bearing engineered to support radial and axial loads in heavy‑truck wheel ends. Designed for SINOTRUK Homan axles, this bearing ensures smooth rotation and long service life under extreme conditions. For guaranteed compatibility and performance, always choose genuine Sinotruk Homan parts.
The 33115 bearing conforms to the international standard 33115 tapered roller bearing, with dimensions 75 mm inner bore, 120 mm outer diameter, and 29 mm width. It is typically used as the outer bearing paired with a larger inner bearing on rear wheel hubs.
The 33115 bearing is a single‑row tapered roller bearing manufactured to ISO 355 and ISO 492 standards. Its tapered rollers and raceways are precision‑ground to ensure optimal rolling contact and minimal friction. This bearing is typically positioned on the outer side of the rear wheel hub, paired with a larger bearing (e.g., 33216X2) on the inner side. Its compact design allows easy preload adjustment via a spindle nut.
Made from vacuum‑degassed 100Cr6 (AISI 52100) bearing steel, the 33115 is heat‑treated to 60‑64 HRC. The raceways are superfinished to a surface roughness Ra ≤ 0.1 μm, reducing friction and heat generation. A high‑strength steel cage guides the rollers evenly, suppressing noise and vibration. The bearing is open (no integral seal) and relies on the hub seal for contamination protection.
Compared to aftermarket bearings, the genuine SINOTRUK Homan 33115 offers superior dimensional consistency, tighter clearance control, and much higher fatigue life. It is 100% tested for radial runout (≤0.015 mm) and internal clearance (C3 standard). This ensures smooth wheel rotation, even brake pad wear, and extended tire life.
Dynamic load rating (C) 78 kN, static rating (C0) 108 kN. Withstands heavy cornering loads and road shocks.
ISO 492 class P6 (P5 optional). Radial runout ≤ 0.015 mm ensures consistent preload and low hub vibration.
Fully interchangeable with standard 33115 bearings. Direct fit for SINOTRUK Homan and many other heavy‑truck axles.
| OEM Number | 33115 |
| Product Name | 33115 Tapered Roller Bearing (Outer Bearing – Rear Wheel Hub) |
| Brand | SINOTRUK Homan |
| Bore Diameter (d) | 75 mm |
| Outer Diameter (D) | 120 mm |
| Width (T – total) | 29 mm |
| Cone Width (B) | 29 mm |
| Dynamic Load Rating (C) | 78 kN (17,500 lbf) |
| Static Load Rating (C0) | 108 kN (24,300 lbf) |
| Limiting Speed (grease) | 3200 rpm |
| Material (rings & rollers) | 100Cr6 (AISI 52100) vacuum degassed |
| Hardness | 60‑64 HRC (through‑hardened) |
| Cage Material | Pressed steel (stamped) or PA66 glass‑fiber reinforced |
| Tolerance Class | ISO 492 P6 (standard) / P5 upon request |
| Radial Runout (max) | 0.015 mm |
| Internal Clearance | C3 (standard) |
| Lubrication | High‑temp wheel bearing grease (NLGI #2) or oil bath |
| Application | Outer position of rear wheel hub, paired with a larger inner bearing |
| Compatible Axles | SINOTRUK Homan HOWO, A7, T7H, C7H drive axles; many heavy‑truck hubs |
The 33115 bearing is manufactured on high‑speed grinding lines that control every dimension to within microns. The raceways are ground and then honed to a superfinish, reducing friction and operating temperature. The rollers are micro‑blasted to remove surface stress risers, then sorted into grades to ensure uniform diameters for each bearing set.
The internal geometry is optimized to distribute load evenly across each roller, preventing edge loading that can cause spalling. The cage is designed to provide low friction and excellent oil flow. Each bearing is 100% noise‑tested (SQF) and 100% inspected for radial runout and axial play. The result is a bearing that runs quietly and lasts for hundreds of thousands of kilometers.
The 33115 is also known as the outer bearing because it is smaller and fits on the outboard side of the hub, while a larger bearing (such as 33216X2) supports the inboard side. Proper preload between the two bearings is set by a slotted nut and measured by rotational torque. The genuine SINOTRUK Homan bearing ensures that preload remains consistent over the life of the bearing.
The 100Cr6 bearing steel is vacuum‑degassed to remove non‑metallic inclusions, which are the primary cause of fatigue cracking. The heat treatment is a controlled martempering process that produces a fine martensitic structure with retained austenite below 5%. This ensures dimensional stability and resistance to micro‑pitting.
The surface hardness of 60‑64 HRC provides excellent wear resistance, while the core retains toughness to absorb impacts. The bearing is coated with a light rust preventive oil; before installation, it should be cleaned and packed with high‑quality NLGI #2 wheel bearing grease.
The 33115 is a direct replacement for the original outer bearing on SINOTRUK Homan rear hubs. The bearing is installed by pressing the cone onto the spindle and the cup into the hub bore. Never apply force through the rollers. After installation, the preload nut is tightened to a specific torque (typically 200 Nm) then backed off and retorqued to a final value of 30‑50 Nm, followed by a 45‑60° angle, depending on the axle type.
Always replace both the inner and outer bearings as a set, and always use a new hub seal. Grease the bearing cavity to 30‑50% fill. Excessive grease causes overheating; too little causes starvation.
1) Raise the vehicle, remove the wheel, brake caliper, and hub cap. 2) Remove the spindle nut and washer, then slide the hub off the spindle. 3) Drive out the old outer bearing cup from the hub using a brass drift and hammer; remove the cone from the spindle.
4) Clean the spindle and hub bore thoroughly; inspect for wear or scoring. 5) Press the new cup into the hub using a press or a bearing driver that contacts only the cup’s outer ring. 6) Press the new cone onto the spindle, again using a press sleeve that contacts the inner ring face.
7) Grease the bearing (both cone and cup) with high‑quality wheel bearing grease. 8) Install the hub onto the spindle, then install the outer bearing, washer, and nut. 9) Tighten the nut to 200 Nm while rotating the hub, then back off one full turn. Re‑tighten to 50 Nm, then add 45‑60° final angle. Measure rotational torque (should be 0.5‑1.5 Nm). 10) Install a new hub seal and reassemble.
The 33115 bearing requires periodic inspection of wheel bearing end‑play or rotational torque. Excessive end‑play (more than 0.05 mm) indicates that the bearing is worn or the preload has loosened. Grumbling or rough rotation suggests roller or raceway damage.
Common causes of premature bearing failure: water ingress (failed hub seal), over‑greasing (overheating), under‑greasing (metal‑to‑metal contact), or incorrect preload. Always replace the hub seal when the bearing is serviced. For heavy‑duty off‑highway operation, repack bearings every 50,000 km or 12 months.
Never mix bearing components from different manufacturers – always use a complete 33115 set from one source. A mismatched cone and cup will have incorrect internal clearances and will fail quickly.
The 33115 bearing is manufactured in an IATF 16949 and ISO 14001 certified facility. Each bearing is 100% inspected for bore, OD, width, runout, and internal clearance using automated CMM and laser gauges. Random samples are tested for hardness, microstructure, and fatigue life (L10 > 3000 hours at rated load). Additional validation includes a 500‑hour debris test, a 200‑hour salt spray (corrosion) test, and a 1,000‑hour thermal cycling test (-40°C to +120°C).
The bearing meets or exceeds ISO 355 (metric tapered roller bearing dimensions) and ISO 492 (tolerances). A laser‑etched batch number on the outer ring (cup) provides full traceability. Counterfeit bearings often have mismatched markings, rough surfaces, or missing brand stamps. Always purchase from authorized SINOTRUK Homan distributors and scan the QR code on the packaging.
A fleet of 650 SINOTRUK HOWO dump trucks in Canadian oil sands replaced outer wheel bearings with the 33115 genuine bearing. Over 2 years, wheel‑end failures dropped by 85% and bearing life increased from 8,000 hours to over 18,000 hours. The sealed, clean bearings eliminated contamination‑related spalling.
Another user – a long‑haul carrier in Europe – reported that after switching to genuine 33115 bearings, the average distance between hub overhauls increased from 300,000 km to 550,000 km. Additionally, brake pad wear became more even due to reduced hub wobble.
Each genuine 33115 bearing is packed in a greaseproof paper wrapper, then placed in a heavy‑duty carton with foam inserts. The box includes a holographic sticker and a QR code for authenticity verification. The bearing itself has the SINOTRUK Homan logo and the OEM number laser‑etched on the cup (outer ring).
Counterfeit bearings often have a rough finish, no laser marking, or a rusty appearance. The genuine bearing rotates smoothly with no detectable roughness. Always scan the QR code before installation. Using a fake bearing can cause overheating, wheel wobble, and even wheel detachment – a major safety hazard.
Summary: The SINOTRUK Homan 33115 Outer Bearing (Rear Hub) delivers high load capacity, precision tolerances, and exceptional durability for heavy‑duty wheel ends. Ensure safe and reliable wheel rotation – choose this genuine component trusted by fleets and mechanics worldwide.
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