How to Choose the Right Fender for Utility Trailers, Enclosed Trailers, and Car Haulers

Selecting the correct trailer fender depends on more than just wheel size. Utility trailers, enclosed trailers, and car haulers each place different demands on fender strength, installation method, and clearance requirements.

This guide explains how to choose the proper fender for each trailer type based on load rating, tire size, material, and usage conditions.

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1. Understanding the Differences Between Trailer Types

Utility Trailers

• Light- to medium-duty hauling

• Common wheel sizes: 13”, 14”, 15”, 16”

• Frequent loading and unloading

• Often stepped on during use

Enclosed Trailers

• Medium- to heavy-duty hauling

• Customers often prefer clean aesthetics

• Fenders sit flush against the outer wall

• Require corrosion resistance for long-term exposure

Car Haulers / Equipment Trailers

• Heavy loads

• Larger wheels: 16” and 17.5”

• Require maximum rigidity

• Often welded directly to frame

• Fender failure risk is higher due to load and vibration

Each trailer type benefits from specific fender sizes and materials.

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2. How to Choose Fenders for Utility Trailers

Utility trailers are highly versatile, but the correct fender choice depends on usage:

Best Fender Size (Single Axle)

• 28”–32” length

• 9”–10” width

• 12–15” height

Best Fender Material

• Steel (14G or 16G) → Durable and weldable

• Diamond plate → Slip-resistant, stronger for stepping

• Aluminum → Lightweight and corrosion-resistant

Best Mounting Method

• Bolt-on or weld-on depending on the trailer

• Bolt-on for DIY or easy replacement

• Weld-on for strength and rigidity

When to Upgrade

• Frequent commercial use

• Hauling heavy lawn equipment

• Stepping on the fender during loading

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3. How to Choose Fenders for Enclosed Trailers

Enclosed trailers require fenders that match the flat outer wall and clean design.

Typical Sizes

• Single axle: 28”–32”, 9”–10” width

• Tandem axle: 72”, 9”–10” width

Material Recommendations

• Aluminum → Most common (corrosion-resistant, clean look)

• Steel → Stronger, but requires coatings

• Diamond plate aluminum → Popular aesthetic upgrade

Why Aluminum Is Preferred

• Does not rust

• Lightweight

• Easy to mount with bolts

• Matches trim and exterior paneling

When Steel Is a Better Choice

• Heavy-duty enclosed trailers

• Car haulers with enclosed sides

• Trailers frequently used off-road

Mounting Notes

Enclosed trailers typically use bolt-on fenders to avoid heat transfer and panel warping when welding.

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4. How to Choose Fenders for Car Haulers & Equipment Trailers

These trailers carry the heaviest loads and require the strongest fenders.

Correct Fender Size

Almost all equipment trailers use:

✔ 72×10×17 teardrop fenders (industry standard)

or

✔ 72×9×17 fenders for narrower 15–16” tires

Material Recommendations

• 14-gauge steel → Standard

• 13-gauge steel → Heavy commercial duty

• Diamond plate steel → Added grip and rigidity

Why Steel Is Mandatory

Car haulers experience:

• High vibration

• Heavy axle loads

• Frequent stepping and tie-down activity

• Exposure to ramps and loading edges

Steel provides the necessary stiffness and resistance to bending.

Mounting Method

Weld-on is strongly recommended for car haulers to avoid:

• Bracket flex

• Bolt shearing

• Fender shift under heavy load

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5. Clearance Requirements for All Trailer Types

Vertical clearance

• 2–4 inches above tire

Horizontal clearance

• 1 inch minimum on each side

Tandem axle tire spacing

• 3–4 inches between tires

These standards keep your fenders from rubbing during compression or heat expansion.

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6. Summary Guide: Best Fender by Trailer Type

Trailer Type	Best Size	Best Material	Best Mount
Utility Trailer	28–32” (SA) / 72” (TA)	Steel or aluminum	Bolt-on or weld
Enclosed Trailer	28–32” (SA) / 72” (TA)	Aluminum or diamond plate	Bolt-on
Car Hauler	72×10×17	14G or 13G steel	Weld-on
Equipment Trailer	72×10×17	Diamond plate or 14G steel	Weld-on

 

(SA = Single Axle, TA = Tandem Axle)

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7. Common Mistakes to Avoid

❌ Choosing fenders too narrow for tire width

Always confirm tire section width before choosing a 9” or 10” fender.

❌ Using aluminum on high-load trailers

Aluminum may crack under heavy vibration.

❌ Mounting fenders too close to tires

Maintain proper clearance to prevent rubbing and overheating.

❌ Ignoring axle spacing

Tandem fenders should match standard spacing (33–36”).

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Conclusion

Choosing the correct trailer fender depends on the trailer type, load capacity, tire size, material preference, and mounting requirements. Utility trailers can use a wide range of materials, enclosed trailers benefit from aluminum aesthetics, and car haulers require welded steel teardrop fenders for maximum durability.

Selecting the right fender ensures safety, long-term performance, and compliance with industry standards.