When you’re replacing tires on a trailer, it’s common to ask: “Will an ST225/75R15 work in place of a 235/75R15?” The short answer is yes, in most cases. But let’s break it down so you know exactly what to expect.
Understanding Tire Sizes
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225 or 235: This is the tread width in millimeters. A 235 tire is about 10mm wider than a 225.
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75: The aspect ratio – sidewall height as a percentage of the width. Both have a 75 ratio.
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R: Radial construction.
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15: Fits a 15-inch rim.
Key Differences
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Width: A 235/75R15 tire is slightly wider, offering a bit more contact patch and potentially better stability.
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Overall Diameter: Both share the same aspect ratio and rim size, so the difference in height is minor. A 235/75R15 is just a touch taller, which might create a small speedometer variance.
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Load Rating: Trailer-specific tires (ST) are built with stronger sidewalls to handle vertical loads better than passenger or light truck tires of similar size.
Practical Implications
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Fitment: Check your fenders and wheel wells. A wider 235 tire might rub at full suspension travel or when turning.
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Load Capacity: ST225/75R15 trailer tires often carry a higher load rating, making them better suited for heavy trailer use. Always confirm the specific tire’s load index before swapping.
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Ride & Performance: The 235 may ride a little smoother on the road, while the ST225 is designed to hold up under trailer loads without sidewall flex.
Pro Tip from the Shop
If you’re running a trailer, stick with ST-rated tires whenever possible. They’re engineered for trailer duty with higher load capacity and stiffer sidewalls. If you’re swapping from a 235/75R15 to an ST225/75R15, it usually works fine as long as you confirm clearance and match the load rating to your trailer’s requirements.
Related Products You May Need
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ST225/75R15 Trailer Tire & Wheel Combos
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Trailer Wheel Lug Nuts and Studs
Trailer Parts Unlimited – 631 TX 75 N, Huntsville TX 77320
Exit 118 off I-45, next to Pilot and Chicken Express
Pickup or shipping available