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BMW non M Gear ratio Swap set - Essential for Differential Gear ratio change
RD3049
191,00€ - 344,00€
BMW Gear Ratio Swap Set — Complete Installation Kit (168 / 188 / 210 mm)
Thinking of changing the gear ratio of your BMW differential? The RacingDiffs Gear Ratio Swap Set includes all essential components to complete a precise, reliable swap and unlock better acceleration, drivability, and overall performance.
Key Features
- Complete kit: Everything required for a seamless gear ratio change with factory-level precision.
- Performance gains: Tailor acceleration, top speed and gear spacing to your driving style and tracks.
- OEM-grade quality: Components meet or exceed OEM specs for durability and long service life.
What’s in the Box
- Adjustment Shim Set / C-Clip Set — ensures proper alignment and backlash adjustment.
- Pinion Oil Seal — maintains lubrication and prevents leaks.
- Large Pinion Bearing — to press onto the new pinion gear.
- Crush Sleeve Shim — for setting correct pinion preload.
- Pinion Depth Shim Set (3.3–3.7 mm) — precise pinion depth positioning.
Performance Benefits
- Stronger acceleration with shorter final drives; or reduced cruising RPM with taller ratios.
- Improved drivability by matching ratio to engine power band and tire diameter.
- Long-term reliability when preload/backlash are set correctly during assembly.
- Expert support — guides and resources to help you complete the swap confidently.
Fitment Confirmation
- Use the BMWFans.info database: Follow this guide video to identify your differential type and parts: How to check diff type.
- VIN check: Send us the last 7 digits of your VIN and we’ll confirm the correct set for your car: Contact RacingDiffs.
Works with common BMW differential sizes: 168 mm, 188 mm, and 210 mm. Verify exact application before ordering.
Technical Specs / Installation Tips
| Pinion depth | Set using the Pinion Depth Shim Set (3.3–3.7 mm). Verify with contact pattern. |
| Pinion preload | Establish with the Crush Sleeve Shim per BMW specs (feel for smooth rotation, no end play). |
| Backlash | Adjust via Adjustment Shim / C-Clip Set until within spec; measure at ring gear with a dial indicator. |
| Sealing | Install the new Pinion Oil Seal; lightly oil lips; inspect yoke surface for grooves. |
| Fasteners | Clean threads, apply medium-strength threadlocker to ring-gear bolts, torque in a star pattern to BMW spec. |
Re-check preload and backlash after the first heat cycle or track session.
OEM Cross-References (Backlash Adjustment Shims)
| Diff Size | OEM Part Numbers |
|---|---|
| 168 mm | 33139065731 / 33-13-9-065-731 / 33 13 9 065 731 / 33.13.9.065.731 33139065732 / 33-13-9-065-732 / 33 13 9 065 732 / 33.13.9.065.732 33139065733 / 33-13-9-065-733 / 33 13 9 065 733 / 33.13.9.065.733 |
| 188 mm | 33139065734 / 33-13-9-065-734 / 33 13 9 065 734 / 33.13.9.065.734 33139065735 / 33-13-9-065-735 / 33 13 9 065 735 / 33.13.9.065.735 |
| 210 mm | 33139065736 / 33-13-9-065-736 / 33 13 9 065 736 / 33.13.9.065.736 33139065737 / 33-13-9-065-737 / 33 13 9 065 737 / 33.13.9.065.737 |
How-To Video
Step-by-step guide to changing your gear ratio correctly.
If you’re unsure about compatibility, send us the last 7 digits of your VIN and we’ll confirm the correct set for your build.
