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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
4.7 ★★★★★
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Product Reviews
★★★★★ 5
Lovely sandals!
I highly recommend!
These are so comfortable! Right out of the box, they can be worn all day. The velcro-adjustable straps are great for making for a perfect fit. The aren't clunky to wear, even though they appear to be. They're super cute, in my opinion. The sock liner is textile, so feet feel good all day, not slimy, like leather and suede can sometimes make feet feel if socks aren't worn.
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Reviewed in the United States on March 17, 2026
★★★★★ 5
Cute and Comfortable
Size: 10, Color: Black
This is my second pair. I bought the sand color at my local Macy's. I got their last pair. I have issues with back pain and ankle swelling and pain. These are so comfortable I had to get them in Black. The adjustable straps are great. My feet are a little bit wider because of the swelling issues. So if you have very narrow feet these might be a little big. You might want to go down a half a size. But otherwise I wear a size 10 and they fit perfectly. I don't think the picture does the color justice. The black almost looks like velvet, it's very deep and rich. I wore them out today for the first time and got lots of compliments. The footbed is very comfortable with the memory foam. Lots of support. I noticed my back and ankle pain is much better wearing these. I've never owned UGG before. If these hold up really well and continue to stay comfortable, I will be purchasing other styles for fall and winter.
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Reviewed in the United States on May 1, 2026
★★★★★ 5
Great fitting sandals
Size: 7.5, Color: Sand
Great fitting. Beautiful. Fit like a glove. Great to walk in. Great quality. Lightweight. All in one gorgeous sandals.
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Reviewed in the United States on May 11, 2026
★★★★★ 5
My new favorite summer sandal!
Size: 8.5, Color: Bay Fog
I am loving these shoes so far this summer! The color is so cute, perfect for a light summer palette. It's the perfect light purple that doesn't make me look pale or washed out. For reference, I have fair to light neutral skin tone. They are SO comfortable - a little too comfortable for a shoe, it's more comfortable than my ugg slippers! They do take a second to put on as you have to either force your ankle in without unstrapping the back - don't judge me - or undo them. Thankfully they have a strap to help get them on easily. I love these shoes. I am a medium width, but I think these have some wiggle room since both the straps are velcro and adjustable somewhat. They are easy to walk in, hold onto the foot, have been more balanced than some others I have had in this platform style, and are very cushioned to walk in. Slight arch support to me but I have somewhat high arches so if you are more flat footed or standard arch these will give you even better support. Really impressed with these. They are more casual but work with many different outfits from sundresses to jeans. For me, these were a great buy and I will be wearing them all summer.
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Reviewed in the United States on June 7, 2026
★★★★★ 5
Comfort and style
Size: 8.5, Color: Chestnut
Like walking on clouds with support.
Thank you Ugg’s. Perfect size 8.5
Will buy again.
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Reviewed in the United States on June 11, 2026