Everything You Need to Know About the Undertail

A Comprehensive Guide

Motorcycle customization is a popular hobby for enthusiasts, and one particular mod that stands out in the world of biking is the undertail modification. This sleek enhancement not only upgrades the aesthetic appeal of a bike but also has functional benefits. In this guide, we will explore everything you need to know about the undertail: what it is, why it’s so popular, how to install it, and more.

What Is an Undertail?

An undertail refers to a piece of custom bodywork installed underneath the rear seat or tail section of a motorcycle. Typically made of plastic or carbon fiber, it covers the area where the rear fender and other components are located. The primary function of the undertail is to provide a cleaner and sleeker look by concealing wires, exhaust pipes, and other hardware that would otherwise be visible.

Modern motorcycles often come with bulky stock fenders and license plate holders, which may not appeal to all riders. Installing an undertail can transform the rear end of a motorcycle, giving it a sportier and more aerodynamic look. Undertails are particularly popular on sportbikes and street bikes.

Why Is the Undertail Popular Among Bikers?

Motorcycle enthusiasts invest in undertail modifications for various reasons. Below are the key factors driving its popularity:

Aesthetic Appeal

One of the most significant reasons bikers opt for an undertail is its visual impact. Many stock rear fenders are large and cumbersome, detracting from the overall sleek design of sportbikes. The undertail tidies up the bike’s profile, offering a minimalist and aggressive look. It complements the bike’s lines and gives it a professional, custom appearance.

Weight Reduction

Although the weight savings from an undertail installation might be minimal, every gram counts in the world of high-performance motorcycling. Many stock rear fenders are made from heavy materials, while aftermarket undertails are usually constructed from lightweight plastic or carbon fiber. This minor weight reduction can slightly improve the bike’s overall performance, especially in racing scenarios.

Improved Aerodynamics

By smoothing out the rear section of the bike, the undertail can contribute to better aerodynamics. Reducing drag is especially beneficial for riders who prioritize speed, such as those involved in racing or track days.

Enhanced Lighting and Customization

Undertail kits often come with integrated lighting setups that include LED taillights, turn signals, and brake lights. These lights are usually smaller, brighter, and more efficient than stock versions. Many bikers enjoy the customization options that come with undertail kits, allowing them to choose different colors and styles that reflect their personal taste.

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Types of Undertail Kits

There are different types of undertail kits available on the market, catering to various styles of bikes and rider preferences. Below are some of the most common types:

Basic Undertail Kit

A basic undertail kit simply replaces the stock fender, cleaning up the look of the rear end. These kits may not come with additional lighting and are often paired with aftermarket turn signals and brake lights.

Integrated Undertail Kit

An integrated undertail kit includes both the rear fender replacement and custom lighting solutions, such as built-in taillights, brake lights, and turn signals. These are popular among riders who want a comprehensive modification in one package.

Carbon Fiber Undertail

For those seeking a premium, lightweight option, carbon fiber undertails are a popular choice. These kits are typically more expensive but offer the advantage of being both lightweight and extremely durable.

Race Undertail

Designed specifically for track use, race undertails prioritize weight reduction and aerodynamics. They usually eliminate any unnecessary features such as turn signals or license plate holders, focusing purely on performance.

How to Install an Undertail on Your Motorcycle

Installing an undertail is a relatively straightforward process, though it may require some technical knowledge, depending on the bike and kit. Below is a general step-by-step guide to help you understand the process:

Gather Tools and Materials

To install an undertail, you will need basic tools such as screwdrivers, wrenches, and pliers. Depending on the kit, you may also require wire cutters and electrical tape for handling the lighting installation.

Remove the Rear Fenders and Stock Components

Start by removing the rear fender, stock turn signals, license plate holder, and any other components that will be replaced by the undertail. This step usually involves unscrewing bolts and disconnecting any electrical connections for the lights.

Install the Undertail

Once the stock components are removed, fit the undertail into place. Depending on the design of your bike and the kit, you may need to make some adjustments to get the undertail to fit correctly. Ensure that it is securely fastened to the bike frame using the provided screws and hardware.

Reconnect the Lights

If your undertail kit comes with integrated lights, you will need to wire them into the bike’s electrical system. Follow the instructions provided with the kit to ensure proper installation of the taillights, brake lights, and turn signals. Use wire connectors and electrical tape to secure the connections and prevent any shorts.

Reattach the License Plate

Many undertail kits come with a designated area for the license plate. Once the installation is complete, attach your license plate to the specified holder.

Test the Installation

Before hitting the road, double-check all connections and components to ensure everything is working correctly. Test the lights, brake signals, and overall fitment to make sure the undertail is securely attached.

Things to Consider Before Installing an Undertail

While an undertail can greatly enhance the look and performance of your bike, there are some important considerations to keep in mind before committing to the modification.

Legal Implications

In some regions, removing or altering the stock fender and lights may not be road-legal. Make sure to check your local laws regarding motorcycle modifications, particularly if your undertail removes or replaces essential components like turn signals or license plate holders.

Compatibility

Not all undertail kits are compatible with every motorcycle model. Before purchasing an undertail, double-check to ensure that the kit is designed specifically for your bike. Some universal kits may require more extensive modifications to fit correctly.

Skill Level

While many bikers can install an undertail on their own, the process can become complicated if electrical work is involved. If you are not confident in your abilities to install the undertail, consider having it professionally installed to avoid any potential issues.

FAQs

Does an undertail affect a motorcycle’s performance?

While the performance changes may be subtle, an undertail can improve a bike’s aerodynamics and slightly reduce weight, making it more suitable for speed-focused riding.

Can I install an undertail myself, or do I need professional help?

Many bikers can install an undertail themselves with the right tools and a basic understanding of motorcycle mechanics. However, if electrical work or significant adjustments are required, professional installation is recommended.

Is an undertail modification legal?

In some areas, altering the stock fender, lights, or license plate placement may be illegal. Check your local laws to ensure the modification is street-legal in your region.

How much does an undertail kit cost?

The cost of an undertail kit varies widely depending on the brand, materials, and whether it includes integrated lighting. Basic kits can start at around $100, while high-end carbon fiber kits may cost upwards of $300.

Conclusion

The undertail is a popular motorcycle modification that offers a blend of aesthetic improvement, lightweight performance, and aerodynamic efficiency. Whether you’re looking to give your bike a sleeker look or enhance its track performance, an undertail can be a great addition to your motorcycle. Just be sure to check compatibility with your bike, follow the installation instructions carefully, and confirm that the modification complies with local laws before making the switch.

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