Description
Ultimate Guide to Dropout – No 78 – RD Black: Essential Spare Part for Your BMC Bike
If you’re a passionate cyclist who owns a BMC bike, you’ve likely encountered the need for reliable spare parts to keep your ride smooth and efficient. One such crucial component is the Dropout – No 78 – RD Black, a rear derailleur hanger designed specifically for certain BMC models. This guide dives deep into everything you need to know about the Dropout – No 78 – RD Black, from its features and compatibility to installation tips and maintenance advice. Whether you’re dealing with a bent hanger from a trail mishap or simply upgrading your setup, understanding this part can save you time, money, and frustration on the road or path.
What Is the Dropout – No 78 – RD Black?
The Dropout – No 78 – RD Black is a precision-engineered rear derailleur hanger produced by BMC Switzerland. It’s essentially the small but vital piece that connects your bike’s rear derailleur to the frame’s dropout. Made from durable aluminum with a sleek black finish, this hanger ensures proper alignment of your shifting system, preventing chain slips and maintaining optimal gear performance. Unlike generic hangers, the Dropout – No 78 – RD Black is tailored for BMC’s high-performance bikes, offering a perfect fit that enhances overall ride quality.
This part is often overlooked until something goes wrong—like a crash or impact that bends it out of shape. A damaged hanger can lead to poor shifting, increased wear on your drivetrain, or even complete failure during a ride. That’s why having a spare Dropout – No 78 – RD Black on hand is a smart move for any serious rider. Priced at around $59, it’s an affordable investment in your bike’s longevity.

As you can see in the image above, the Dropout – No 78 – RD Black comes as a pair of fixed dropouts, complete with four M6x16mm bolts for easy installation. Its black anodized coating not only matches the aesthetic of many BMC frames but also provides resistance to corrosion and wear.
Compatibility: Which Bikes Does the Dropout – No 78 – RD Black Fit?
Compatibility is key when selecting bike parts, and the Dropout – No 78 – RD Black is no exception. This hanger is specifically designed for BMC models like the 257 AMP and Alpenchallenge AL series, particularly those from 2022 onward. It’s optimized for bikes with rear derailleurs (RD) and is not suitable for models with internal gear hubs. If your bike features stealth cable routing or disc brakes, this hanger integrates seamlessly without compromising the frame’s design.
To confirm if the Dropout – No 78 – RD Black is right for your setup, check your bike’s model year and specifications. For instance, the 257 AMP AMP (2022+) is a perfect match, ensuring that your shifting remains crisp and reliable even on urban commutes or light off-road adventures. If you’re unsure, consult BMC’s official compatibility charts or reach out to a local bike shop. Using the wrong hanger can lead to misalignment, so always double-check.
Here’s a quick compatibility checklist:
- BMC 257 AMP (2022+)
- Alpenchallenge AL models (non-internal gear hub)
- Frames with rear derailleur mounts
- Not compatible with internal gear systems or non-BMC bikes
If your bike is from an earlier year or a different brand, consider alternatives like Wheels Manufacturing’s Derailleur Hanger 78, which offers similar functionality but may require adjustments.
Key Features and Specifications of the Dropout – No 78 – RD Black
What sets the Dropout – No 78 – RD Black apart from standard hangers? Let’s break down its features. Weighing in at approximately 220 grams, it’s lightweight yet robust, minimizing any added bulk to your bike. The black finish isn’t just for looks—it’s anodized for enhanced durability against scratches and environmental elements.
Technical specs include:
- SKU: 30001763
- Material: High-quality aluminum
- Color: Black
- Included Items: 1 pair of fixed dropouts, 4x M6x16mm bolts
- GTIN: 7630027875379
- Activity Suitability: Cycling, urban riding, light touring
This hanger supports flat mount disc brakes and thru-axle systems, making it ideal for modern BMC frames. Its design prioritizes easy replacement, which is crucial since derailleur hangers are intentionally the “weak link” in your bike—they bend or break to protect more expensive components like the frame or derailleur itself.

Pictured here is a BMC bike similar to those compatible with the Dropout – No 78 – RD Black, showcasing how this part fits into a high-performance setup. Riders appreciate its role in maintaining aerodynamic efficiency and smooth power transfer.
Step-by-Step Guide: How to Install the Dropout – No 78 – RD Black
Installing the Dropout – No 78 – RD Black is a straightforward DIY task that most cyclists can handle with basic tools. You’ll need a hex wrench set (typically 5mm), bike grease, and cleaner. Always work in a well-lit area and secure your bike in a stand for safety.
- Prepare Your Bike: Remove the rear wheel by loosening the quick-release or thru-axle. This gives you clear access to the derailleur area.
- Remove the Old Derailleur and Hanger: Use a hex wrench to loosen the mounting bolt on the rear derailleur (turn counterclockwise). Let the derailleur hang from the cable temporarily. Then, unscrew any bolts holding the old hanger in place and gently remove it from the frame’s dropout.
- Clean the Area: Wipe down the dropout area with bike cleaner to remove dirt, grease, or debris. This ensures a secure fit for the new hanger.
- Install the New Hanger: Align the Dropout – No 78 – RD Black with the frame’s mounting points. Insert the provided M6x16mm bolts and tighten them securely (torque to about 8-10 Nm to avoid over-tightening). Apply a bit of grease to the threads for smooth installation and future removal.
- Reattach the Derailleur: Screw the derailleur back onto the new hanger using its mounting bolt. Ensure it’s aligned properly—use a derailleur hanger alignment tool if available for precision.
- Reinstall the Wheel and Test: Put the rear wheel back on, shift through all gears, and take a short test ride. Adjust the derailleur limits if shifting feels off.
If you’re new to bike maintenance, watch tutorial videos for visual guidance. Professional installation at a bike shop costs around $20-30 and is worth it if you’re unsure.
Benefits of Using the Dropout – No 78 – RD Black
Investing in the Dropout – No 78 – RD Black offers several advantages. First, it restores your bike’s shifting precision, which is essential for efficient pedaling and speed control. Cyclists report smoother gear changes and reduced chain noise after replacement.
Durability is another plus—the aluminum construction withstands daily use while being sacrificial in crashes, protecting your frame. For urban commuters on the 257 AMP, this means fewer breakdowns during rush hour rides. Off-road enthusiasts on Alpenchallenge models benefit from its compatibility with disc brakes, ensuring reliable stopping power.
Compared to aftermarket options, the genuine BMC Dropout – No 78 – RD Black guarantees a perfect fit, reducing the risk of compatibility issues. Users on forums praise its ease of installation and value for money, though specific reviews are sparse due to its niche nature.
Maintenance Tips for Your Dropout – No 78 – RD Black
To maximize the lifespan of your Dropout – No 78 – RD Black, regular maintenance is key. Inspect it after every rough ride for bends or cracks. Clean the area with a soft brush and mild soap, avoiding high-pressure washers that could force water into bearings.
Apply lubricant sparingly to moving parts, but keep the hanger itself dry to prevent attracting dirt. If you notice shifting problems, check hanger alignment immediately—a bent one can wear out your cassette prematurely.
Store spare parts like the Dropout – No 78 – RD Black in a dry, cool place. Consider carrying one in your toolkit for long tours.

This close-up of a similar BMC dropout illustrates the precision engineering that goes into parts like the Dropout – No 78 – RD Black.
Where to Buy the Dropout – No 78 – RD Black
You can purchase the Dropout – No 78 – RD Black directly from BMC’s official website or authorized dealers like Bike24 and eBay. Prices hover around $59-$83 depending on the retailer, with free shipping often available. Look for bundles that include related parts, such as kickstand mounts for the 257 AMP.
Online marketplaces offer quick delivery, but verify authenticity to avoid counterfeits. Local bike shops may stock it or order it for you, providing expert advice.
Alternatives and Comparisons
If the Dropout – No 78 – RD Black isn’t available, consider the Wheels Manufacturing DROPOUT-78, compatible with similar frames like Yeti models. It’s priced lower at $27.50 but may require modifications. For internal gear hubs, BMC’s Dropout #79 is a direct alternative.
In comparisons, the Dropout – No 78 – RD Black stands out for its OEM quality and exact fit, outperforming generics in durability tests.

Here’s another variant of a BMC dropout for reference, highlighting design similarities.
Conclusion: Why the Dropout – No 78 – RD Black Is a Must-Have
In summary, the Dropout – No 78 – RD Black is an indispensable spare part for BMC owners seeking reliability and performance. Its precise engineering, easy installation, and compatibility make it a top choice for maintaining your bike’s drivetrain. Whether you’re a daily commuter or weekend warrior, keeping this hanger in top shape ensures every ride is enjoyable and trouble-free.
If you’ve experienced issues with your current setup, upgrading to the Dropout – No 78 – RD Black could be the solution. Share your thoughts or experiences in the comments below—have you installed one yourself?







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