Shipping Estimate
USA
- USA
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- USA
- CAN
Ships within 48 hours · Estimated delivery Jul 7 - Jul 12
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Description
diff gear ratio BMW M Gear Ratio Swap Set | M3, M5, M6, Z4M Differential UpgradeBMW M Gear Ratio Swap Set Complete Installation Kit Enhance the performance and driving experience of your BMW M3, M5, M6, and Z4 M with the RacingDiffs Gear Ratio Swap Set. The kit includes all essential components to change your differentials gear ratio with factory level precision and reliability. Key Features Complete kit: All parts required for a precise, repeatable gear ratio swapno guesswork. Performance gains: Tailor acceleration and
BMW M Gear Ratio Swap Set — Complete Installation Kit
Enhance the performance and driving experience of your BMW M3, M5, M6, and Z4 M with the RacingDiffs Gear Ratio Swap Set. The kit includes all essential components to change your differential’s gear ratio with factory-level precision and reliability.
Key Features
- Complete kit: All parts required for a precise, repeatable gear-ratio swap—no guesswork.
- Performance gains: Tailor acceleration and drivability to your use case (street, track, time attack).
- OEM-level precision: Components manufactured to meet or exceed OEM specifications.
- Guided install: Step-by-step tutorial + video walkthrough linked below.
What’s in the Box
- Adjustment Shim Set — aligns and positions internal components correctly.
- Pinion Oil Seal — prevents leaks and maintains optimal lubrication.
- Large Pinion Bearing — required to install onto the new pinion from your new gear set.
- Crush Sleeve Shim — sets the correct pinion bearing preload.
- Pinion Position Shim Set (2.5–3.5 mm) — precise pinion depth adjustment.
Performance Benefits
- Stronger acceleration with the right final drive for your build and tracks.
- Optimized top-end and gear spacing for your engine’s power band.
- Long-term reliability when backlash and preload are set correctly.
- Expert support from RacingDiffs if you need guidance selecting shims or ratios.
Technical Specs / Installation Tips
| Use case | Gear ratio change on BMW M differentials (see fitment variants below). |
| Pinion setup | Set pinion depth using the Pinion Position Shim Set (2.5–3.5 mm) and establish correct preload with the Crush Sleeve Shim. |
| Backlash | Adjust with the Adjustment Shim Set until backlash is within spec; verify gear contact pattern with marking compound. |
| Sealing | Install the new Pinion Oil Seal; lightly oil lips; ensure no nicks on yoke surface. |
| Torque notes | Clean threads; apply medium-strength threadlocker on ring-gear bolts; torque in a star pattern per BMW spec. |
| OEM references | Backlash adjustment shims: 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) |
Tip: Always re-check preload/backlash after first heat cycle or track day.
Fitment (Variants)
Variant 1 (V1):
- E36 M3 (3.2 S52)
- E46 M3
- E28 M5, M535
- E34 M5
- E39 M5
- E24 M6
- E60 M5
- E63 / E64 M6
- Z4 M
Variant 2 (V2):
- E90 / E92 / E93 M3
If you’re unsure about compatibility, send us the last 7 digits of your VIN and we’ll confirm the right set for your car.
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy