How to Measure Your Trailer for the Perfect Fender Fit
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Finding the right trailer fender isn’t just about looks — it’s about safety, compliance, and performance. A fender that’s too small leaves your wheels exposed, while one that’s too big can rub, rattle, and cause costly damage. Measuring correctly before you buy ensures a perfect fit the first time.
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Why Fender Fit Matters
• Safety – Protects vehicles and pedestrians from road debris.
• Compliance – Many states require specific coverage for trailer tires.
• Longevity – A proper fit reduces vibration and stress on mounting points.
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Tools You’ll Need
• Tape measure
• Notepad or phone for recording dimensions
• Flashlight (for tight spaces)
• Helper (optional, but speeds things up)
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Step 1: Measure the Fender Length
1. Place your tape measure along the top outer edge of your current fender (or wheel opening if no fender).
2. Measure from the front edge to the rear edge.
3. Record the measurement in inches.
Pro Tip: If you’re replacing an old fender, match the length as closely as possible to avoid drilling new holes.
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Step 2: Measure the Fender Height
1. Measure from the bottom mounting point (usually near the trailer frame) to the highest point of the fender curve.
2. This determines clearance over the tire.
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Step 3: Measure the Fender Width
1. Place the tape measure across the widest part of the fender.
2. Make sure you account for tire bulge — the widest point of the tire, not just the tread.
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Step 4: Wheel Size & Axle Count
• Single axle trailers usually need smaller fenders.
• Tandem axle trailers require longer, double-wheel coverage.
• Write down your tire diameter (e.g., 15”, 16”). This ensures you buy a fender that fully covers the tire.
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Step 5: Material & Mounting Style
Once you have the measurements:
• Decide between bolt-on, weld-on, or bracket-mounted fenders.
• Choose your material: steel for strength, aluminum for rust resistance, plastic for lightweight affordability.
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Trailer Fender Size Chart
|
Tire Size |
Typical Fender Length |
Typical Fender Height |
Typical Fender Width |
|
13”–14” |
60” |
10”–12” |
9”–10” |
|
15”–16” |
72” |
12”–14” |
10”–12” |
|
17”+ |
80”+ |
14”+ |
12”+ |
Common Measuring Mistakes
• Only measuring the tire instead of the mounting space.
• Forgetting to check state fender coverage laws.
• Not allowing for suspension travel — tires need space to move upward.
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Final Step: Order the Perfect Fender
Now that you know your exact measurements, you can shop with confidence.