Differences in Appearance and Structure between DU and DAC Wheel Hub Bearings
- Visual Appearance (without disassembly)
DAC (ball type): Both ends have flat sealing covers, mostly black/red rubber seals, and a smooth cylindrical outer ring; for example, model name DAC39720037, size format DAC inner diameter × outer diameter × width. Commonly used in front/rear wheels of passenger cars, sedans, and small SUVs.
DU (roller type): Also cylindrical in shape, but with a stronger sealing structure (mostly ACM seals); model name DU25520037. Commonly used in vehicles with higher load capacities: SUVs, pickup trucks, and light trucks, bearing greater loads.
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⚠️ It is difficult to distinguish them by appearance alone; you must check the engraved model number or disassemble to examine the Rolling Elements.
- Internal Core Differences (Most Crucial)
① DAC: Rolling elements are Steel Balls, double-row steel balls, point contact; high speed, low noise; lower load capacity, cannot withstand excessive impact loads.
② DU: Rolling elements are Tapered Rollers, tapered rollers, line contact; large radial and axial loads, strong impact resistance; significantly higher load capacity than DAC for the same size; disadvantage: slightly higher noise at high speeds.
3. Concise Comparison Table
| Item | DAC | DU |
| Rolling element | Steel balls | Tapered rollers |
| Contact form | Point contact | Line contact |
| Load capacity | Medium | High, heavy-duty |
| Rotating speed | High, low noise | Medium, slightly higher noise |
| Applicable vehicles | Sedans, small SUVs | SUVs, pickup trucks, light-duty trucks |
| Sealing | Ordinary rubber seal | Mostly ACM high-performance seal |