The Foundation of Your Sur-Ron’s Rear End
First, the rear swingarm is a critical structural component of your Sur-Ron Light Bee X. It connects the rear wheel, shock absorber, and chassis, transmitting power from the motor to the ground while supporting the rear suspension . Whether you need a direct OEM replacement or are looking to upgrade for high-performance riding, choosing the right swingarm transforms your bike’s stability and handling .
OEM Factory Swingarm (Stock Replacement)
The original equipment manufacturer (OEM) swingarm is a forged aluminium alloy component designed specifically for the Sur-Ron Light Bee X platform . It serves as the baseline for all aftermarket comparisons.
| Specification | OEM Value |
|---|---|
| Material | Forged aluminium alloy |
| Length | Approx. 465mm (stock) |
| Weight | Approx. 2.021 kg (4.456 lb) |
| Application | Light Bee X, LBX, L1E |
The factory cast frame works for light riding but shows limits with harder use . Riders pushing beyond 6kW often experience flex, “ghost steering,” and compromised cornering confidence .
EBMX Extended Swingarm – +60mm Length
The EBMX billet swingarm is the most popular aftermarket upgrade for the Sur-Ron Light Bee X . CNC-machined from aerospace-grade billet aluminium, this swingarm extends the wheelbase by 60mm (2.4 inches) for dramatically improved high-speed stability .
| Feature | EBMX Specification |
|---|---|
| Material | Aerospace-grade billet aluminium |
| Length Extension | +60mm longer than OEM |
| Weight | 3.5 kg (0.6 kg lighter than EBMX V1) |
| Sprocket Compatibility | 54T-58T, and 64T rear sprockets |
Key Benefits:
- Extended Length for Stability: The extended geometry improves rear wheel traction and stability, especially valuable in high-power, off-road conditions . This means better control, smoother landings, and improved handling under acceleration.
- Reinforced CNC-Machined Design: Built from aerospace-grade billet aluminium with tight tolerances and greater durability than the cast OEM part .
- Improved Mud & Debris Clearance: Precision-cut channels actively shed dirt and debris, reducing buildup and minimising maintenance .
- Chain Guide Compatibility: Integrated support for a chain guide system (sold separately) that works with 54T-64T sprockets for torque-focused setups .
Installation Requirements:
- Chain replacement required: Due to the extended design, your existing chain will be too short. You will need a new chain with approximately 12 additional links .
- Recommended shock upgrade: A longer swingarm increases forces transferred into the rear shock. EBMX recommends pairing with the EBMX YSS rear shock and linkage for optimal performance .
KyVex Billet Swing Arm
The KyVex billet swing arm is a premium USA-made option for Sur-Ron Light Bee X owners seeking maximum strength . Fully CNC-machined from billet aluminum, this swingarm was built specifically for riders who have outgrown the limits of the stock cast setup .
| Feature | KyVex Specification |
|---|---|
| Construction | Fully CNC-machined billet aluminum |
| Fitment | Sur-Ron Light Bee X |
| Price | $945.00 |
| Lead Time | 7-8 weeks for first batch |
KyVex is built for harder riding, more power, and less flex. It’s ideal for builders creating a full custom setup or riders pushing their bike beyond stock limits .
Defiant Welded Swingarm – Zero-Flex Design
The Defiant Emoto Swingarm takes a different engineering approach—using aerospace-grade alloys and proprietary welding techniques to achieve a rigidity rating that outperforms CNC-only arms while staying lighter than stock .
Comparison Table:
Length Options:
- OEM Length: For agility and responsive handling
- +1.5″ Extended: For moderate stability improvement
- +2.5″ Extended: For maximum high-speed stability and wheelie control
OEM Replacement Parts: Bearings and Bushings
For maintenance and rebuilds, genuine OEM pivot components are available to restore proper swingarm function.
| Component | Weight | Price | Application |
|---|---|---|---|
| Swingarm Pivot Bearing | 0.001 kg | Varies | OEM replacement, 12-month warranty |
| Frame/Swingarm Bushing | N/A | £2.99 | Light Bee X L1E, reduces play |
These components ensure smooth, responsive suspension movement and accurate alignment under load. Over time, bushings can degrade due to load, dirt ingress, and regular off-road or road use—replacing them restores a solid, controlled feel to the rear end .
Swingarm Comparison Table
Why Upgrade Your Swingarm?
The stock Surron swingarm was designed for 6kW of power . If you’ve upgraded to a 72V system or are pushing 15kW+, you’ve likely felt the “ghost steering” and rear-end flex that kills confidence in corners .
Signs you need an upgrade:
- Rear-end wobble or instability at high speed
- Vague cornering feel under hard acceleration
- Visible flex in the swingarm during aggressive riding
- Upgraded controller/motor pushing beyond 10kW
Benefits of upgrading:
- Improved high-speed stability – Extended swingarms keep the front wheel planted
- Reduced flex – Billet and welded designs eliminate twist under torque
- Larger sprocket support – Run 54T-64T for maximum torque
- Better cornering confidence – Predictable rear-end behavior
Which Swingarm Should You Choose?
Choose OEM replacement if:
- You have a damaged stock swingarm and want a direct factory replacement
- You ride stock power levels (6kW or less)
- You prefer simple bolt-in installation without chain or shock changes
Choose EBMX Extended if:
- You want the proven industry standard for high-power builds
- You’re running 54T-64T sprockets for maximum torque
- You’re willing to upgrade your chain and consider a shock upgrade
Choose KyVex if:
- You want USA-made billet craftsmanship
- You’re building a custom show-quality bike
- You can wait 7-8 weeks for delivery
Choose Defiant if:
- You’re pushing extreme power (20kW-30kW+)
- You want zero flex with lightweight construction
- You need a welded design proven for 30kW+ verified torque
Installation Considerations
Before purchasing any aftermarket swingarm, consider these requirements:
- Chain length: Extended swingarms require a longer chain (typically +12 links for EBMX)
- Shock compatibility: Extended swingarms increase leverage on the rear shock; OEM shocks may not perform well
- Sprocket selection: Larger sprockets (54T-64T) require compatible chain guide systems
- Tools & expertise: Swingarm replacement requires mechanical knowledge and appropriate tools
Pros and Cons Summary
Pros of Aftermarket Swingarms:
- Massive strength upgrade over OEM cast aluminum
- Extended length improves high-speed stability and cornering
- Dirt-shedding design improves reliability
- Supports larger sprocket setups for torque-focused riding
- CNC-machined tolerances for perfect fitment
Cons of Aftermarket Swingarms:
- Premium pricing (670−945+)
- Requires new chain (additional cost)
- May require upgraded rear shock for optimal performance
- Extended length changes bike geometry and handling character
- Installation takes time and mechanical skill
Who Needs an Upgraded Swingarm?
A Sur-Ron rear swingarm upgrade is perfect for:
- High-power builders pushing 10kW-30kW through upgraded controllers
- Riders experiencing rear-end flex or instability at speed
- Off-road enthusiasts tackling rough terrain and jumps
- Stunt riders needing precise control under hard acceleration
- Racers seeking maximum cornering confidence
Why Choose the Right Swingarm for Your Build?
In conclusion, the Sur-Ron rear swingarm is a critical component that directly impacts your bike’s handling, stability, and power delivery . For stock power levels, the OEM forged swingarm provides adequate performance . For high-performance builds, aftermarket options from EBMX, KyVex, and Defiant offer significant improvements in rigidity and geometry .
The extended 60mm design of the EBMX swingarm dramatically improves high-speed stability and allows for larger sprockets up to 64T . The Defiant swingarm offers zero-flex construction verified for 30kW+ torque, making it the ultimate choice for extreme builds . The KyVex billet option provides USA-made precision for custom builders .
For serious riders pushing their Sur-Ron to the limit, upgrading the rear swingarm is one of the most impactful chassis modifications you can make. Paired with a quality rear shock and proper chain setup, an aftermarket swingarm transforms your Light Bee X into a more stable, confident, and capable machine .
For more Sur-Ron performance parts, browse our Collection of Sur-Ron Upgrades or read our E-Moto Build Guide.
