Yes. Electro & Company offers a Big Wheel Conversion Kit for the ETM RTR platform, allowing you to upgrade from the stock wheel sizes to a larger off-road setup.

Wheel Sizes

Why do I need different gearing?

Unlike a traditional gas-powered motorcycle, the ETM RTR uses a direct-drive electric powertrain.

When you increase the diameter of the rear wheel, you effectively change the overall gear ratio. A larger rear tire travels farther with each revolution, which makes the gearing "taller."

Without correcting the gearing, the motor has to work significantly harder to produce the same acceleration and climbing power.

This results in:

• Reduced acceleration
• Lower wheel torque
• Increased motor temperatures
• Increased controller temperatures
• Reduced overall performance
• Higher current draw

For these reasons, changing the sprocket ratio is required when installing larger wheels.

Recommended Gear Ratios

2025 ETM RTR & 2025/2026 ETM RTR Lite

Stock wheels / 12" Mag Wheels / 12" Supermoto

• 9 Tooth Front
• 73 Tooth Rear
• #35 Chain - 114 Link

Big Wheel Kit / 14" Street Wheel Kit

• 9 Tooth Front
• 86 Tooth Rear
• #35 Chain - 140 Link Universal

2026 ETM RTR Sport / ETM RTR Alpha

Stock wheels (14"/12")  / 12" Mag Wheels / 12" Supermoto

• 8 Tooth Front
• 55 Tooth Rear
• 420 Chain for 12 inch wheel

Big Wheel Kit / 14" Street Wheel Kit

• 8 Tooth Front
• 63 Tooth Rear
• 420 Chain for 14 inch wheel

2026 ETM RTR XL

Stock wheels (17"/14") / 14" Street Wheel Kit

• 8 Tooth Front
• 63 Tooth Rear
• 420 Chain for 14 inch wheel

12" Mag Wheels / 12" Supermoto

• 8 Tooth Front
• 55 Tooth Rear
• 420 Chain for 12 inch wheel

Will changing the gearing affect performance?

Yes—but when using the recommended gearing with the Big Wheel Kit, the overall performance characteristics remain very similar to the stock configuration.

The recommended sprocket ratios were specifically developed to compensate for the increase in rear wheel diameter. By increasing the rear sprocket size, the overall final drive ratio is brought back in line with the original design, allowing the bike to maintain nearly the same balance of:

• Acceleration
• Top speed
• Low-end torque
• Thermal management
• Overall rideability

In most riding conditions, riders should notice minimal difference in overall performance compared to the stock wheel setup. But you may notice that the bike is smoother over rough technical terrain because of the larger wheels. 

Note: A larger rear sprocket by itself (while retaining the stock wheel size) would increase low-end torque and acceleration while reducing top speed. However, when paired with the larger rear wheel in the Big Wheel Kit, the sprocket increase is intended to offset the change in wheel diameter—not significantly alter the bike's performance characteristics.

This gearing combination has been optimized by Electro & Company to provide the best balance of performance, efficiency, and powertrain reliability with the larger wheel setup.

Can I keep the stock sprocket or install a smaller one?

No. This is not recommended.

Using a larger rear wheel with the stock gearing—or an even smaller rear sprocket—creates an excessively tall final drive ratio.

This can lead to:

• Severe performance loss
• Poor acceleration
• Excessive motor temperatures
• Excessive controller temperatures
• Reduced efficiency
• Increased stress on the entire powertrain

Electro & Company has extensively tested and optimized the ETM RTR gear ratios to provide the best balance of:

• Top speed
• Acceleration
• Torque
• Rideability
• Thermal management
• Overall reliability

Running gearing outside of our recommended specifications can cause the powertrain to operate beyond its intended design limits.

Important: Damage resulting from improper gearing combinations—including using oversized wheels without the recommended sprocket ratio—may void the 6-Month Limited Powertrain Warranty.

Our Recommendation

If you're upgrading to the ETM RTR Big Wheel Kit, always install the recommended sprocket size for your model at the same time.

This ensures your bike maintains the performance, reliability, and thermal management that the ETM RTR platform was engineered to deliver.