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Description
diff gear ratio BMW Differential Gear ratio Swap set - Essential for smooth gear ratio changeBMW 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,
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 |
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.
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
4.4 ★★★★★
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Product Reviews
★★★★★ 5
Addicting
Format: Paperback
Very good! Read the whole thing in the span of 2 days, would read again!!
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Reviewed in the United States on August 31, 2025
★★★★★ 4
so good
Format: Kindle
It’s rare I get a book and literally can’t put it down and in the brief moments I did all I could think about is what Happens next.
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Reviewed in the United States on March 2, 2026
★★★★★ 5
made me homesick in the best way.
Format: Kindle
I’m not good at reviews but this book was a beautiful disaster. I need to know of the story right now. lol.
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Reviewed in the United States on April 13, 2025
★★★★★ 3
cowgirl romance say what
Format: Paperback
When a city girl inherits a horse farm from her estranged late aunt. she never expects to fall head over heels for the grumpy hot farrier who dislikes her. Molly McDaniel's life is not going great, her crushing student loans haunt her, her back to back jobs to just get by take up most of her time, and her dream of starting an event planning business has been put on the backburner. When she gets news that she has inherited her late estranged aunt's run down, struggling horse barn, this could be her chance to finally get her life back in track if she can sell it.... yet when she gets there she meets Shani, the hot cocky farrier who was close to her aunt and who dislikes Molly for being the one to inherit the horse farm. Shani refuses to give up on the barn and dislikes Molly for even thinking about wanting to sell it. Molly knows she can't take care of the horse farm, she has no experience, yet the longer she spends there getting to know all the people who were working on it with her aunt and actually spending more time with Shani, she begins to fall in love with both the farm and Shani. Will Molly risk it all and keep the farm and try and convince Shani that she means to stay, or will she finally chase after her dreams and take the easy way out? This was a really easy to read cowgirl romance, but it just felt like it was missing something for me. I was hoping for some further development in the romance or some actual chemistry, but it just wasn't there for me. I really wanted to like this one but just felt like it was okay at best and that it could have been better. I would say out of all the Jennifer Dugan books I've read, this was the best one. Molly and Shani are opposites and dislike each other from the start but work to overcome their differences and stop fighting their attraction to one another. It's a easy contemporary farm girl x city girl romance and I think anyone who enjoys a sapphic romance should definitely give it a go.
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Reviewed in the United States on June 9, 2024
★★★★★ 4
Betting the farm
Format: Kindle
Shani and Molly meet after Molly unexpectedly inherits the horse farm that Shani expected to be hers. The two butt heads as Molly figures out what she wants to do with the farm. Both women are gun shy due to ghost from theirs past but they can't deny the chemistry between them. Just when it looks like they might get their happily ever after, betrayal from a friend throws a wrench in the works. This was a really good read with well structured characters and an engaging storyline.
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Reviewed in the United States on March 14, 2025