Radius-Style Trailer Fenders: Advantages, Sizes, and Fitment Requirements

Radius-style trailer fenders are a widely used alternative to teardrop and diamond plate fenders. Known for their clean arch, simple profile, and universal compatibility, radius fenders are popular on both single-axle and tandem-axle trailers across multiple industries.

This guide explains what radius fenders are, the advantages they offer, and how to ensure proper fitment.

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1. What Are Radius-Style Trailer Fenders?

A radius-style trailer fender features a smooth, consistent arch across its entire length—from one end of the fender to the other. Unlike teardrop fenders, radius fenders do not include a center dip or teardrop indentation.

Key Characteristics

• Full-radius curve without flat sections

• No center drop between wheels (for tandem versions)

• Works for single or tandem-axle setups

• Available in steel, aluminum, and diamond plate

• Compatible with bolt-on or weld-on mounting

Radius fenders offer simplicity in design, making them a versatile choice for many trailer types.

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2. Advantages of Radius Trailer Fenders

1. Clean, Simple Design

The uniform curved profile gives a polished look suitable for:

• Utility trailers

• Commercial trailers

• Enclosed cargo trailers

• Boat trailers

• Custom builds

2. Universal Fitment

Radius fenders are easy to size because they follow a predictable curve. This consistency makes them easier to match with many wheel sizes and trailer designs.

3. More Material Options

Because the profile is simpler than teardrop designs, radius fenders are commonly available in:

• Aluminum

• Steel (14G, 16G, 13G)

• Diamond plate

Aluminum radius fenders are especially common on boat trailers.

4. Lightweight Options Available

Aluminum radius fenders provide strong corrosion resistance and reduced weight without sacrificing basic functionality.

5. Less Stress on Weld Points

With a smooth arch, stress is distributed evenly across the fender. This decreases the chance of cracking compared to fenders with sharp angles or flat sections.

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3. Common Radius Fender Sizes

Radius fenders come in a variety of lengths, widths, and heights depending on the axle setup.

Single-Axle Radius Fenders

Common sizes include:

• 28” length

• 30” length

• 32” length

• 9” or 10” width

• 12–15” height

These typically fit 13”–16” wheels.

Tandem-Axle Radius Fenders

Popular options include:

• 69” length

• 72” length

• 9” or 10” width

• 16–18” height

Though teardrop fenders dominate the heavy-duty market, radius fenders remain popular for lighter tandem builds.

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4. Which Wheel Sizes Work Best with Radius Fenders?

Radius fenders are compatible with:

Single-Axle

• 13” wheels

• 14” wheels

• 15” wheels

• 16” wheels

Tandem-Axle

• 15” wheels (most common)

• 16” wheels

• 10-inch widths are ideal for higher-profile tires

While radius fenders can fit 17.5” wheels, teardrop fenders provide stronger structural alignment and are preferred for heavy-duty setups.

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5. Material Choices and Their Implications

Steel Radius Fenders

• Strong, durable

• Available in 14G or 16G

• Easy to weld

• Good for utility and commercial trailers

Aluminum Radius Fenders

• Lightweight

• Rust-proof

• Ideal for boat trailers

• Usually bolt-on

Diamond Plate Radius Fenders

• Added grip

• Extra rigidity

• Strong visual appeal

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6. Fitment Requirements for Radius Fenders

Accurate fitment relies on matching fender dimensions to wheel diameter and axle spacing.

For Single-Axle Trailers

Verify:

• Tire diameter (e.g., 24”–30”)

• Tire width

• Required coverage area

• 2–4 inches of vertical clearance

• Mounting bracket alignment

For Tandem-Axle Trailers

Verify:

• Axle spacing (center-to-center)

• Tire-to-tire clearance

• Required fender length (often 69” or 72”)

• Clearance under full suspension travel

Radius fenders should cover the top arc of both tires without interfering with suspension movement.

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7. Weld-On vs Bolt-On for Radius Fenders

Weld-On

• Best for steel fenders

• Provides strongest mount

• Ideal for heavy or commercial use

Bolt-On

• Best for aluminum fenders

• Easy to replace

• Ideal for saltwater exposure

Radius fenders are extremely compatible with both methods due to their smooth profile.

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8. When to Choose Radius Fenders Over Teardrop

Select radius fenders when:

✔ You want a simpler, more universal design

✔ You are using aluminum (common for boat trailers)

✔ You prefer bolt-on installation

✔ You have non-standard axle spacing

✔ You want a lightweight setup

Choose teardrop fenders if you need maximum rigidity for heavy loads.

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Conclusion

Radius-style trailer fenders offer a clean, simple design with universal fitment options for both single-axle and tandem-axle trailers. Their smooth arch distributes stress evenly, making them a durable and versatile choice across multiple trailer types. Whether made from steel, aluminum, or diamond plate, radius fenders provide reliable protection and long-term performance when sized and installed properly.