Both work for trailers, but they suit different towing styles.

• Radial (ST205/75R14): The tread and belts run radially around the tire, which can help it run cooler at highway speeds and promote steadier tracking and longer tread life during frequent road use.
• Bias (ST205/75D14): Layers of cord crisscross, creating a sturdy sidewall that can handle occasional rugged surfaces and storage. They’re often a practical, budget-friendly choice for lighter or shorter trips.

Choose based on how you use your trailer: regular highway miles lean radial, occasional or mixed-use can lean bias. For stable handling, keep the same construction on each axle. Always check your trailer placard and follow tire and wheel specifications.

The size is the same (205 width, 75 aspect ratio, 14-inch rim). The letter is the difference:

• D: Bias-ply construction (crisscrossed plies). Often chosen for durability and occasional-use trailers.
• R: Radial construction (belts run radially). Often preferred for cooler running and consistent highway manners.

Overall diameter and width are typically similar, but exact specs can vary by model and load range (e.g., C, D). For predictable handling, avoid mixing radial and bias on the same axle. Stick with ST (Special Trailer) tires, match your trailer’s load requirements, and confirm your 14-inch trailer rim is rated for the tire’s load and inflation pressure.

Load range indicates a tire’s capacity and recommended inflation range. As a general guide:

• Load Range D: A higher-capacity option than C in many ST205/75 14-inch sizes, commonly used on small to mid-size trailers.
• Load Range E: Higher capacity and higher inflation than D, with a firmer ride. Availability can vary by size.

Pick the load range that meets or exceeds your trailer’s axle ratings and cargo needs without exceeding your wheel’s pressure rating. Upgrading load range alone doesn’t increase your trailer’s legal capacity. Many trailer tires achieve their rated capacity only at their listed cold inflation; follow tire sidewall, wheel markings, and your trailer placard for safe, compatible setup.

It’s a common guideline some owners use when changing sizes: keep overall tire diameter changes modest—often cited around 3%—to help maintain clearance, suspension geometry, and predictable tracking.

• Why it’s used: Helps reduce the chance of fender or frame contact and alignment changes.
• Tandem axles: Keep tires closely matched in diameter across both axles to limit scrub and uneven wear.
• How to check: Compare manufacturer diameter specs or revolutions per mile, and confirm fender and frame clearance with the trailer loaded.

When switching between ST205/75D14 and ST205/75R14, overall size is typically similar, but it’s still a good idea to verify the specific tire’s measurements.

“5 on 4.5” means five lugs on a 4.5-inch bolt circle. These wheels fit hubs with the same pattern.

• Confirm your pattern: Check your hub or trailer manual for the bolt circle specification (e.g., 5 on 4.5).
• Check clearances: Make sure the wheel’s center bore clears the hub and that its load and pressure ratings match your trailer’s needs.
• Match components: A 5 on 4.5 wheel won’t fit hubs with a different pattern (like 5 on 5).

Many ST205/75 14-inch tire-and-wheel assemblies on this page are offered in 5 on 4.5. Verifying the pattern and ratings before buying can help ensure a straightforward install.