Description
Exploring the Dropout – No 70 Black: Your Ultimate Guide to BMC Bike Maintenance and Upgrades
In the world of cycling, maintaining your bike’s performance is crucial, especially for enthusiasts who ride high-end models like those from BMC. One essential component that often goes unnoticed until it’s needed is the rear derailleur hanger. Today, we’re diving deep into the Dropout – No 70 Black, a specialized part designed to keep your shifting smooth and your rides uninterrupted. Whether you’re a seasoned cyclist or just starting to tinker with your bike, this guide will cover everything you need to know about this key spare part.

Understanding the Role of a Derailleur Hanger in Your Bike
Before we get into the specifics of the Dropout – No 70 Black, let’s take a step back and explain what a derailleur hanger actually does. Also known as a dropout, this small but vital piece attaches the rear derailleur to your bike’s frame. It’s typically made from aluminum or other durable materials to absorb impacts and protect the more expensive frame and derailleur from damage during crashes or rough terrain.
Why is it important? In modern road and gravel bikes, precise shifting is everything. A bent or broken hanger can lead to poor gear changes, chain drops, or even complete drivetrain failure. Replacing it promptly ensures your bike stays in top condition. According to cycling experts, regular inspections of this component can prevent costly repairs down the line. For BMC owners, the Dropout – No 70 Black is a perfect example of a manufacturer-specific part that blends functionality with reliability.
Key Features of the Dropout – No 70 Black
The Dropout – No 70 Black stands out for its robust design tailored to 12-speed systems. Crafted from high-quality materials, it features a sleek black anodized finish that not only looks professional but also resists corrosion and wear. This hanger is engineered for direct attachment, making it compatible with leading derailleur brands.
One notable aspect is its compatibility with SRAM 11 and 12 speeds, Shimano 11 and 12 speeds (with direct attachment), and Campagnolo 12 speeds. It’s particularly recommended for SRAM 12-speed derailleurs, where it excels in providing stable shifting performance. The part includes essential hardware like a screw and adapter, ensuring you have everything needed for a straightforward replacement.
Weighing in at around 14 grams, it’s lightweight yet sturdy, minimizing any added bulk to your bike. The engraving “SR12” on the hanger indicates its optimization for 12-speed setups, a detail that highlights BMC’s attention to precision engineering.

Compatibility: Which BMC Models Does It Fit?
Compatibility is a top concern when shopping for bike parts, and the Dropout – No 70 Black is designed specifically for select 2020 BMC models. Here’s a breakdown:
- Teammachine SLR01 and SLR02 Disc Brake (MY20): Ideal for these high-performance road bikes, ensuring seamless integration with disc brake systems.
- Roadmachine 01 and 02 (MY20): Perfect for endurance road riders who need reliable shifting on long hauls.
- URS (MY20): Suited for gravel adventures, where durability is key.
- Timemachine Road 01 (MY20): Enhances aero performance in time trial setups.
This hanger is optimized for 12-speed derailleurs, but note that for Shimano setups, it requires a B-link adapter. If your bike falls outside these models, consider checking BMC’s full lineup of dropouts, as there are variations like No. 72 or others for different years.
To confirm fit, always cross-reference the manufacturer part number: 302109. This ensures you’re getting the genuine Dropout – No 70 Black and not a generic alternative that might compromise performance.
Step-by-Step Installation Guide for the Dropout – No 70 Black
Installing the Dropout – No 70 Black is a task most cyclists can handle at home with basic tools. Here’s a detailed guide to get you started:
- Gather Tools: You’ll need a 5mm Allen key, torque wrench (set to 8-10 Nm), and possibly chain whip if adjusting the derailleur.
- Remove the Old Hanger: Shift to the smallest cog, remove the rear wheel, and unscrew the old hanger from the frame. Inspect for damage.
- Prepare the New Part: Align the Dropout – No 70 Black with the frame’s mounting points. Insert the provided screw and adapter.
- Attach and Torque: Secure it firmly but avoid over-tightening to prevent stripping threads.
- Reinstall Derailleur and Wheel: Reattach the derailleur, adjust limits if needed, and test shifts across all gears.
- Test Ride: Take a short spin to ensure smooth operation.
Pro tip: If you’re using a SRAM 12-speed system, this hanger provides optimal alignment for crisp shifts. For visual learners, many online tutorials demonstrate similar installations on BMC bikes.
Benefits of Upgrading to the Dropout – No 70 Black
Why choose the Dropout – No 70 Black over aftermarket options? For starters, it’s an OEM part from BMC, guaranteeing perfect fit and longevity. Users report improved shifting precision, especially in demanding conditions like gravel or hilly terrains.
In terms of protection, this hanger acts as a sacrificial component—if you crash, it bends instead of your frame, potentially saving hundreds in repairs. Its black finish also matches most BMC frames aesthetically, maintaining that sleek look.
Compared to generic hangers like those from Wheels Manufacturing (which offer a similar #70 model for $27.50), the BMC version ensures brand-specific compatibility without compromises. Cyclists on forums praise its durability, with some noting it lasts through seasons of intense use.
Maintenance Tips to Extend the Life of Your Dropout – No 70 Black
To get the most out of your Dropout – No 70 Black, regular maintenance is key. Clean it after muddy rides to prevent grime buildup, and inspect for bends every few months. Lubricate the threads lightly during installation to ease future removals.
If you’re into bikepacking or racing, consider carrying a spare Dropout – No 70 Black in your toolkit—it’s compact and could save a trip. Pair it with high-quality chains and cassettes for optimal drivetrain health.
Where to Buy the Dropout – No 70 Black and Pricing Insights
The Dropout – No 70 Black is available from official BMC dealers and online retailers. On the BMC Switzerland site, it’s priced at USD 39.00, with stock readily available for quick shipping. Other sites like Bike24 or eBay offer it around the same range, sometimes with bundles including tools.
Look for authorized sellers to avoid counterfeits. In Europe, prices hover around €35-40, depending on the retailer.
User Reviews and Real-World Performance
While official reviews are sparse, cyclists on platforms like Amazon and cycling forums appreciate the Dropout – No 70 Black for its reliability. One user noted, “It fitted perfectly on my Roadmachine 02 and restored shifting like new.” Another highlighted its value in gravel riding, where impacts are common.
No major complaints surface, though some wish for more color options beyond black. Overall, it’s rated highly for quality and ease of use.
Conclusion: Is the Dropout – No 70 Black Right for You?
If you own a compatible BMC bike and value precision engineering, the Dropout – No 70 Black is an excellent investment. It combines durability, compatibility, and affordability to keep your rides smooth and worry-free. Whether replacing a damaged part or stocking up for emergencies, this hanger exemplifies BMC’s commitment to excellence.






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