Do I Need to Change the Wheel Rim When Replacing 750 Tires with 825?
2 Answers
Yes, the wheel rim needs to be changed. The most basic requirement for tire upgrading is that the tire diameter should be equal or have minimal difference (not exceeding 1% more or 2% less than the original). The original tire diameter is 750mm, and you want to replace it with 825mm. (825-750)/825 = 9%, which far exceeds the diameter requirement. Tire upgrading is unrelated to the rim diameter but is related to the overall diameter. Here is more relevant information: Introduction to tires: The international code for radial tires is "R," commonly known as "steel-belted tires." The arrangement of the cord plies in radial tires differs from that in bias-ply tires. In radial tires, the cords are not arranged in a crisscross pattern but are nearly parallel to the tire's cross-section, resembling the Earth's meridians. The cord angle is small, usually 0°, and there are no intersecting points between the cord plies. When the tire is in motion, the stress around the crown increases, leading to axial extension and radial cracks in the tire body.
Switching from 750 tires to 825 tires means the tires are over half an inch wider, which significantly increases the likelihood of needing to change the rims. With over a decade of truck driving experience, I've seen drivers who skipped replacing the rims and directly installed wider tires. The result? Severe vibrations within days, uneven wear on the tire edges, and even compromised braking performance. If the rim width doesn't match, the new tires won't be securely fixed, making them prone to deformation and detachment when hitting potholes, which can lead to serious accidents. To be safe, I always recommend measuring the rim specifications first—check if the diameter and width of the old rims align with the recommended values for the new 8.25 tires. If you don't have the tools, it's best to visit a professional shop and have a technician measure with calipers. Spending a little money upfront can save you from major repair hassles later. While changing rims might sometimes cost more, safety should always come first, especially for long-haul transportation where there's no room for error. Also, remember to check tire pressure and balance to ensure proper compatibility with the new tires—this is the foundation of safety for long-distance driving.
