We carry extensive knowledge about trailer tires and understand that choosing the right ones is crucial for safe hauling and long-lasting performance. What does ST225 75R15 mean on your trailer tires? These markings aren't random numbers – they reveal essential information about your tire's construction and capabilities.
When it comes to trailer tire codes, each element tells a specific story about the tire's design. ST225/75R15 breaks down into precise measurements and specifications that directly impact how your trailer performs under heavy loads and long-distance hauling. The ST225/75R15 measures 28.3 inches in diameter with an 8.9-inch tread width and fits on a 15-inch rim. These tires also feature robust sidewalls measuring 6.7 inches, delivering superior stability and minimizing trailer sway during transport.
We'll break down each component of the ST225/75R15 marking, examine its exact dimensions, and compare it with similar options like the ST205/75R15. Load ratings are equally important, and we'll explain how they affect your hauling capacity. Understanding these specifications helps you select the right trailer tires for your specific applications, whether you're transporting equipment, pulling a travel trailer, or hauling valuable cargo across long distances.
Understanding the ST225/75R15 code is essential before selecting trailer tires. Each number and letter provides specific information about the tire's construction and capabilities that directly impact your hauling performance.
The "ST" designation stands for Special Trailer, indicating tires engineered exclusively for trailer applications. ST tires feature significantly thicker sidewalls compared to passenger vehicle tires, designed to handle substantial vertical loads rather than the lateral forces experienced during steering. These tires are built to track straight behind your tow vehicle, with tread patterns optimized for following rather than steering responsibilities. ST tires should never be mounted on motorized vehicles - their construction is specifically designed for trailer use only.
The "225" indicates the tire's section width measured in millimeters from sidewall to sidewall. This translates to approximately 8.9 inches of tread width. Wider tires typically provide enhanced stability and create a larger contact patch with the road surface. The ST205/75R15 measures 205mm (approximately 8.1 inches) wide, making the ST225/75R15 nearly an inch wider for improved road contact.
The number "75" represents the aspect ratio - the relationship between sidewall height and tire width expressed as a percentage. For the ST225/75R15, the sidewall height equals 75% of the 225mm width, calculating to 168.75mm or roughly 6.64 inches. This ratio affects load-carrying capacity and ride characteristics. Both ST225/75R15 and ST205/75R15 share the same 75% aspect ratio, but their actual sidewall heights differ due to the different base widths.
The "R" identifies radial construction, where internal cords run perpendicular (90 degrees) to the tire's centerline. Radial tires deliver superior performance compared to bias ply alternatives (designated with "D"): they operate cooler, offer better highway handling, improve fuel efficiency, and typically last longer. Radial design features cords running straight across from bead to bead with steel belts beneath the tread, creating enhanced flexibility and better road surface conformity.
The final number "15" specifies the wheel diameter in inches required for proper mounting. ST225/75R15 tires accommodate 15-inch diameter rims with widths ranging from 6 to 6.5 inches. This compatibility range provides flexibility when selecting wheels for your specific trailer setup.
Understanding the exact dimensions of ST225/75R15 trailer tires makes the difference between proper fitment and potential problems. These measurements directly affect load capacity, handling characteristics, and overall trailer performance.
ST225/75R15 tires measure 28.3 inches in total diameter when properly inflated. Most manufacturers maintain this consistent measurement, though some report slight variations up to 28.4 inches. This diameter determines ground clearance and affects speedometer readings. The measurement also controls how well the tire fits within your trailer's wheel wells and plays a key role in proper load distribution across axles.
The section width measures 8.9 inches (225 millimeters), creating a substantial road contact patch. Some manufacturers list this as 8.8 inches, a minor difference that comes from varying measurement methods. This wider footprint delivers better highway stability and improved handling during long hauls. Looking for quality ST225/75R15 tires at competitive prices? Find the best selection and discount prices of ST 225/75R15 Tires.
The 6.7-inch sidewall height results from multiplying the tire width (225mm) by the aspect ratio (75%). This robust sidewall construction provides excellent load-bearing capacity and absorbs road shock effectively. The sidewall represents approximately 24% of the tire's total diameter, giving ST225/75R15 tires their distinctive trailer-specific profile.
These tires fit 15-inch diameter wheels with rim widths between 6 to 6.5 inches. Some manufacturers allow rim widths up to 7 inches, but always verify specifications with your tire manufacturer. Mounting on incompatible rim widths can cause premature wear or complete failure. The correct rim width ensures proper bead seating and maintains the optimal sidewall shape during operation.
Trailer owners often need to choose between ST225/75R15 and ST205/75R15 tires. Understanding the key differences between these sizes helps you make the right decision for your specific hauling requirements.
The ST225/75R15 stands 28.3 inches in overall diameter, towering 1.2 inches above the ST205/75R15's 27.1-inch height. Width differences are equally significant - the ST225 spans 8.9 inches compared to the ST205's 8.1-inch width, creating nearly 0.8 inches of additional tread surface. The sidewall measurements also differ, with the ST225 featuring 6.6 inches versus the ST205's 6.1 inches.
Load capacity represents the most critical difference between these tire sizes. ST225/75R15 tires deliver a maximum capacity of 2,830 pounds per tire at 80 PSI. ST205/75R15 tires max out at 2,150 pounds per tire at 65 PSI. This translates to substantial differences in total trailer capacity - four ST225 tires support approximately 11,320 pounds versus 8,600 pounds for ST205 configurations.
Rim compatibility varies between these sizes. The ST205/75R15 accommodates a broader range of rim widths from 5 to 6.5 inches, while ST225/75R15 tires require 6 to 6.5-inch wide rims. Find the best selection and discount prices of ST 225/75R15 Tires for your trailer upgrade needs.
Upgrading makes sense when you need additional load capacity for heavier trailers or cargo. Check clearance requirements carefully - you'll need approximately 5/8-inch extra height and 1/2-inch additional width on each side. For dual tire setups, maintain at least 3 inches between tires when upgrading to the larger size.
Load ratings represent the most critical factor when selecting ST225/75R15 trailer tires, directly determining how much weight your trailer can safely transport. Understanding these ratings prevents dangerous overloading situations that can lead to tire failure.
ST225/75R15 tires are available in two primary load ranges that affect their strength and capacity. Load Range D tires feature 8-ply rated construction and require maximum inflation of 65 PSI. Load Range E tires offer superior 10-ply rated construction capable of handling up to 80 PSI. The construction difference directly impacts the tire's ability to maintain proper air pressure under load—the key factor that actually supports your trailer's weight.
Load capacity varies dramatically between these ratings. Load Range D tires support up to 2,540 pounds per tire, while Load Range E tires handle 2,830 pounds each. For heavy-duty applications, specialized all-steel trailer tires with 14-ply rating (Load Range G) can support up to 3,197 pounds per tire.
These tires excel on travel trailers, pop-up campers, boat trailers, toy haulers, and fifth wheels. Car haulers, utility trailers, cargo trailers, and equipment haulers benefit significantly from the ST225/75R15's robust construction. The Carlisle Radial Trail HD version specifically handles off-road towing demands, providing excellent traction on unpaved surfaces.
Most ST225/75R15 tires carry M speed ratings (81 mph maximum) or N ratings (87 mph maximum). Radial construction delivers superior highway performance compared to bias ply designs—running cooler with reduced rolling resistance. This results in extended tread life and improved handling at highway speeds.
Looking for reliable ST225/75R15 trailer tires? Find the best selection and discount prices of ST 225/75R15 Tires for your specific hauling needs.
Understanding ST225/75R15 tire codes gives you the knowledge needed to make smart choices for your trailer's safety and performance needs. We've broken down every element of these important markings, explaining how the Special Trailer designation and precise measurements directly impact your hauling capabilities. The ST225/75R15 delivers solid performance with its 28.3-inch diameter, 8.9-inch width, and robust 6.7-inch sidewalls designed for excellent towing stability.
Comparing the ST225 to the smaller ST205/75R15 reveals substantial differences in capability. The larger ST225 handles approximately 2,720 pounds more total weight with four tires, making it the better choice for heavier trailers and substantial cargo loads. The wider footprint also delivers superior highway stability and reduces trailer sway during long hauls.
Load Range selection plays a crucial role in tire performance. Load Range D (8-ply construction) works well for lighter applications, while Load Range E (10-ply construction) provides the strength needed for maximum capacity hauling. Matching your specific trailer weight and cargo needs to the right load range ensures safe operation and longer tire life.
When you're ready to purchase replacement tires, finding the best selection and discount prices of ST 225/75R15 Tires becomes your next step. Quality tires protect both your investment and your cargo while delivering the peace of mind that comes with proper equipment.
You now have the information needed to select trailer tires that match your exact requirements. The right tires provide the foundation for confident towing, whether you're hauling work equipment locally or taking your RV on cross-country adventures. Choose wisely, and your trailer will serve you well for years to come.
Understanding your ST225/75R15 tire code ensures you select the right trailer tires for safety, performance, and proper load capacity.
• ST225/75R15 breaks down into specific measurements: ST = Special Trailer, 225 = 8.9" width, 75 = sidewall aspect ratio, R = radial construction, 15 = wheel diameter
• These tires offer superior load capacity: Load Range E supports up to 2,830 pounds per tire versus ST205/75R15's 2,150 pounds maximum
• Proper fitment requires 15-inch rims between 6-6.5 inches wide with overall tire diameter of 28.3 inches and 6.7-inch sidewall height
• ST tires are exclusively for trailers, never motorized vehicles due to their specialized construction with thicker sidewalls for vertical loads
• Choose Load Range D (65 PSI) for lighter trailers or Load Range E (80 PSI) for heavier RVs, car haulers, and equipment trailers requiring maximum capacity
The right tire selection directly impacts your trailer's safety, stability, and ability to handle heavy loads during highway travel and long-distance hauling.
The date code on trailer tires is typically a four-digit number. The first two digits represent the week of manufacture, and the last two digits indicate the year. For example, "4117" means the tire was made in the 41st week of 2017.
The recommended air pressure for ST225/75R15 trailer tires depends on their load range. Load Range D tires typically require 65 PSI, while Load Range E tires need 80 PSI for maximum load capacity. Always check your tire's sidewall or manufacturer specifications for the exact recommended pressure.
"ST" stands for Special Trailer. This designation indicates that the tire is specifically designed for use on trailers and should not be used on motorized vehicles. ST tires have thicker sidewalls to handle heavy vertical loads and are engineered for trailing rather than steering.
The ST225/75R15 tire typically offers a higher load capacity compared to the ST205/75R15. A Load Range E ST225/75R15 tire can support up to 2,830 pounds per tire, while an ST205/75R15 generally maxes out at 2,150 pounds per tire. This means a set of four ST225/75R15 tires can handle approximately 2,720 pounds more total load than ST205/75R15 tires.
ST225/75R15 tires are ideal for a wide range of trailers, including travel trailers, pop-up campers, boat trailers, toy haulers, and fifth wheels. They're particularly well-suited for car haulers, utility trailers, cargo trailers, and equipment haulers due to their higher load capacity and stability. Some versions, like the Carlisle Radial Trail HD, are also designed for excellent performance on unpaved surfaces.
