Ultimate Guide to the Fourstroke AMP LT Drive Unit Small Part Kit – No 1 AS: Essential Upgrades for Your BMC eMTB

If you’re an avid mountain biker who loves tackling rugged trails with the added boost of electric assistance, then maintaining your ride is crucial for peak performance. One essential accessory that often flies under the radar but can make a significant difference is the Fourstroke AMP LT Drive Unit Small Part Kit – No 1 AS. This kit is designed specifically for the BMC Fourstroke AMP LT series, ensuring your drive unit stays protected and functional during intense rides. In this comprehensive guide, we’ll dive deep into what this kit offers, how it fits into your eMTB setup, and why it’s a must-have for enthusiasts. Whether you’re a seasoned rider or new to electric mountain bikes, understanding these components can help extend the life of your bike and enhance your overall experience on the trails.

The BMC Fourstroke AMP LT is a standout in the world of lightweight eMTBs, known for its whisper-quiet TQ-HPR50 motor that delivers 50Nm of torque while keeping the total weight under 35 pounds. This down-country bike features 120mm of front and rear suspension travel, making it ideal for cross-country adventures and technical descents. With its integrated 360Wh battery and advanced APS dual-link suspension, it’s engineered for efficiency and agility. But like any high-performance machine, it requires regular maintenance, especially around the drive unit, which is the heart of the e-assist system.

Introducing the 2023 BMC Fourstroke AMP LT – All the details about the new light eMTB and its TQ HPR 50 motor | E-MOUNTAINBIKE Magazine

Understanding the BMC Fourstroke AMP LT: A Quick Overview

Before we delve into the specifics of the Four stroke AMP LT Drive Unit Small Part Kit – No 1 AS, it’s worth exploring the bike it’s made for. The Fourstroke AMP LT is part of BMC’s amplified trail lineup, blending the agility of a traditional XC bike with the power of electric assistance. Released in 2022, this model uses the innovative TQ-HPR50 drive system, which is compact, lightweight (just 1.85kg for the motor), and nearly silent, allowing riders to focus on the trail without distracting noise.

Key features of the Fourstroke AMP LT include:

• Frame and Suspension: A full carbon frame with 120mm travel via RockShox or Fox components, optimized for climbing and descending.
• Drivetrain: Often equipped with SRAM GX Eagle or higher, providing smooth shifting across varied terrain.
• Wheels and Tires: 29-inch wheels with up to 2.4-inch tires for excellent grip and rollover capability.
• Battery and Range: The 360Wh internal battery offers ample range for long rides, with options for a range extender.
• Weight: Starting around 15.8kg (34.8 lbs), it’s one of the lighter eMTBs in its class, making it feel more like a non-assisted bike on flats and climbs.

This bike is perfect for riders who want to amplify their progress without sacrificing the natural feel of mountain biking. It’s been praised for its geometry, which shares 95% with the non-electric Four stroke LT, ensuring predictable handling. If you’re pushing your Four stroke AMP LT to its limits on rocky paths or muddy trails, wear and tear on the drive unit is inevitable. That’s where specialized kits come in to keep everything running smoothly.

First Look: BMC Fourstroke AMP LT – Downcountry Motorized – Pinkbike

What Is the Fourstroke AMP LT Drive Unit Small Part Kit – No 1 AS?

The Fourstroke AMP LT Drive Unit Small Part Kit – No 1 AS is a genuine BMC spare parts set tailored for the drive unit of the Fourstroke AMP LT eMTB. Priced around $59, this kit includes essential small components that help secure, protect, and maintain the TQ-HPR50 motor and related systems. It’s particularly useful for replacements during routine maintenance, after impacts, or when upgrading your setup for better durability.

This kit isn’t just a random assortment of bolts; it’s precision-engineered to fit the 2023 model year (MY23) Fourstroke AMP LT perfectly. BMC, a Swiss brand renowned for high-quality cycling innovations, ensures these parts are made from durable materials like Alloy 6061-T6 for spacers and EPDM rubber for plugs, providing resistance to weather, vibrations, and trail debris.

Why might you need it? The drive unit is exposed to elements like mud, rocks, and water splashes during off-road rides. Over time, screws can loosen, covers can crack, and spacers can wear out. Replacing them with this official kit prevents bigger issues, such as motor misalignment or battery instability, which could lead to costly repairs.

Breaking Down the Components: What’s Inside the Kit?

Let’s take a closer look at what you get in the Fourstroke AMP LT Drive Unit Small Part Kit – No 1 AS. Based on official listings, this comprehensive set includes:

• 2x Motor Screws: Hex socket head cap screws, M8x80. These are crucial for securely mounting the motor to the frame, ensuring stability during high-torque outputs.
• 1x Motor Spacer Right: Made from Alloy 6061-T6, a lightweight yet strong aluminum alloy that provides precise spacing on the right side of the drive unit.
• 1x Motor Spacer Left: Similarly constructed from Alloy 6061-T6, this spacer balances the left side for even alignment and vibration reduction.
• 1x Motor Cover for HPR50: A protective bash guard or cover designed specifically for the TQ-HPR50 motor. It shields the unit from impacts and debris, featuring hexagonal cutouts for ventilation and weight savings.
• 2x Battery Screws: Hex socket head cap screws with a special low head, M5x8. These secure the battery in place, preventing rattles or shifts during bumpy rides.
• 2x Motor Cover & LL Mud Protector Screws: Hex socket head cap screws with low head, M3x6. Ideal for attaching the motor cover and lower linkage mud protector.
• 2x Range Extender Cable Clips: These clips organize and secure cables for any range extender setup, reducing clutter and potential snags.
• 2x Rubber Plug Speed Sensor / AXS Cable: Made from EPDM 70 rubber, these plugs seal openings for speed sensors or SRAM AXS wireless cables, keeping out moisture and dirt.

Each piece is black-finished for a seamless match with the bike’s aesthetics, and the materials are chosen for longevity in harsh conditions. This kit weighs minimally, adding no noticeable bulk to your lightweight eMTB.

Fourstroke AMP LT Drive Unit Small Part Kit – No 1 Black – BMC Switzerland AG

Step-by-Step Installation Guide for the Kit

Installing the Fourstroke AMP LT Drive Unit Small Part Kit – No 1 AS is straightforward for those with basic mechanical skills, but if you’re unsure, consult a professional bike mechanic. Here’s a general guide to get you started:

1. Prepare Your Workspace: Lay out all kit components and gather tools like hex keys (Allen wrenches) in sizes 3mm, 5mm, and 6mm, plus torque wrenches for precise tightening.
2. Remove Old Parts: If replacing existing screws or spacers, carefully unscrew them from the drive unit. Inspect the motor area for any damage or dirt buildup.
3. Install Spacers: Position the left and right motor spacers (Alloy 6061-T6) on either side of the TQ-HPR50 unit. Ensure they align with the frame mounts.
4. Secure with Motor Screws: Insert the M8x80 hex screws and tighten to the recommended torque (typically 10-15Nm; check BMC’s manual for exact specs).
5. Attach Motor Cover: Place the HPR50 motor cover over the unit and use the M3x6 screws to fasten it, along with any mud protector.
6. Battery and Cable Management: Use the M5x8 battery screws to secure the battery. Clip in the range extender cables and insert the EPDM rubber plugs into any unused ports.
7. Test and Ride: Power on the bike, check for unusual noises, and take a short test ride to ensure everything feels solid.

Always refer to the official BMC spare parts list or user manual for model-specific torque values to avoid over-tightening, which could strip threads. Proper installation can take 30-60 minutes and significantly improves the drive unit’s protection.

Benefits of Using the Fourstroke AMP LT Drive Unit Small Part Kit – No 1 AS

Investing in this kit offers numerous advantages for eMTB owners:

• Enhanced Protection: The motor cover and mud protector screws safeguard the TQ-HPR50 from rocks and splashes, reducing the risk of expensive motor repairs.
• Improved Durability: High-quality materials like Alloy 6061-T6 ensure spacers withstand vibrations and impacts, prolonging the life of your drive system.
• Better Cable Management: Clips and plugs keep everything tidy, preventing cable damage and maintaining a clean, professional look.
• Weight Efficiency: Adding minimal weight, it aligns with the Fourstroke AMP LT’s lightweight ethos, keeping your bike agile.
• Cost-Effective Maintenance: At around $59, it’s an affordable way to prevent larger issues, especially compared to replacing the entire drive unit.

Riders report that such kits help maintain the bike’s near-silent operation and responsive assistance, making climbs feel effortless and descents more controlled.

Compatibility and Model Considerations

This kit is primarily compatible with the MY23 Fourstroke AMP LT models, including variants like the ONE, TWO, and LTD. It fits bikes equipped with the TQ-HPR50 motor, but double-check your frame’s part number (e.g., 30004287 from BMC’s spare list). If you have an earlier model or a different drive system (like the TQ-HPR60 shown in some comparisons), consult BMC’s compatibility chart.

For owners of other BMC eMTBs, such as the Fourstroke AMP or Twostroke AMP, similar kits exist but may differ in components. Always verify with official sources to ensure a perfect fit.

The BMC Fourstroke LT AMP | Contender Bicycles

Customer Reviews and Real-World Feedback

While specific reviews for the Fourstroke AMP LT Drive Unit Small Part Kit – No 1 AS are limited (as it’s a niche spare part), users of BMC spares generally praise their quality and fit. On forums and retailer sites, riders note that these kits are “essential for trail warriors” and “easy to install with noticeable improvements in protection.” One user mentioned, “After a rocky ride, the motor cover saved my drive unit from a big hit – worth every penny.”

If you’re looking for more insights, check BMC’s official site or cycling communities like Pinkbike or Singletrack World for discussions on eMTB maintenance.

Exploring Alternatives: Other Options for Drive Unit Maintenance

If the Fourstroke AMP LT Drive Unit Small Part Kit – No 1 AS isn’t available or doesn’t suit your needs, consider these alternatives:

• BMC Fourstroke 01 Small Part Kit: For non-AMP models, offering similar screws and spacers but without e-specific components.
• Aftermarket Motor Guards: Brands like OneUp or RRP offer universal bash plates, though they may not fit as precisely.
• TQ Official Spares: Direct from TQ for motor-specific parts, but compatibility with BMC frames varies.
• Full Service Kits: BMC’s broader spare lists include chainguides or thru-axle kits for comprehensive upkeep.

Always prioritize OEM parts for the best integration and warranty compliance.

Conclusion: Elevate Your Ride with Proper Maintenance

In the world of electric mountain biking, small details make a big difference. The Fourstroke AMP LT Drive Unit Small Part Kit – No 1 AS is more than just a collection of screws and spacers – it’s your ticket to reliable, protected performance on every trail. By incorporating this kit into your maintenance routine, you’ll ensure your BMC Fourstroke AMP LT continues to deliver that amplified progress with minimal downtime. Whether you’re replacing worn parts or prepping for a big adventure, this SEO-optimized guide has covered everything from components to installation. Head to your local BMC dealer or online retailer to grab yours today and keep charging those trails!