What size are my RV tires?
Your RV tire size is the size stamped on the tire’s sidewall and is typically listed on the vehicle’s placard. To be confident, check both sources—the sidewall markings and the RV’s owner’s manual or manufacturer specifications. RVs use a wide range of wheel sizes, from 15 inches up to 22.5 inches, so sizes vary considerably across models.
Understanding RV tire size codes
The numbers and letters on a tire sidewall describe its width, profile, construction, and the wheel it fits. Common prefixes include P (passenger), LT (light truck), and ST (special trailer). A typical size reads like 225/75R16, where 225 is the width in millimeters, 75 is the aspect ratio (the height of the sidewall as a percentage of the width), R denotes radial construction, and 16 is the wheel diameter in inches. Load index and speed rating may follow the size code and are essential for safety and performance.
What the letters and numbers mean
This section explains each part of the code and how it affects fit and performance. We’ll cover width, aspect ratio, construction, wheel diameter, and the P/LT/ST prefixes as well as load index and speed rating.
- Width (mm): the tire’s cross-section width, e.g., 205, 225, or 245.
- Aspect ratio (%): the height of the sidewall as a percentage of the width, e.g., 70, 75, or 85.
- R: radial construction (the standard for most RV tires).
- Wheel diameter (inches): the diameter of the wheel the tire fits, e.g., 15, 16, 19.5, or 22.5.
- P, LT, ST prefixes: P = passenger, LT = light truck, ST = special trailer tires.
- Load index and speed rating: numbers/letters after the size code that specify maximum load and operating speed.
Understanding these elements helps you compare tires and ensure you select the right replacement that matches your RV’s requirements.
Common RV tire sizes by vehicle type
RVs come in multiple configurations, and tire sizes vary accordingly. The following patterns illustrate typical approaches, but always verify the exact size printed on your tires and on the OEM placard.
- Travel trailers and smaller RVs: commonly ST or P-metric sizes like ST225/75R15 or P205/75R14, usually on 15"–16" wheels.
- Mid-size travel trailers and larger fifth wheels: often ST235/75R16 or ST275/70R16–ST275/80R22.5 depending on axle and wheel setup.
- Class A motorhomes (large coaches with 22.5" wheels): commonly 275/70R22.5, 275/80R22.5, or 315/80R22.5.
- Class C and smaller motorhomes (16"–19.5" wheels): sizes such as 225/75R16, 235/85R16, 245/75R16, or 275/70R19.5 in some configurations.
Note that these examples reflect widely used patterns, but the exact size depends on the manufacturer and model. Always cross-check with the sidewall and the RV placard. When replacing tires, use the same size, load index, and speed rating as the OEM, and avoid mixing tire types on the same axle unless advised by the manufacturer.
Where to find the exact size on your RV
To confirm your tire size, inspect multiple sources. The following steps help ensure you’re using the right numbers for all tires on the vehicle.
- Inspect the tire sidewalls for the size code, such as 225/75R16 or ST235/80R16—the first number is width, the second is the aspect ratio, the R indicates radial construction, and the last number is the wheel diameter in inches.
- Check the placard near the driver’s door or inside the RV’s documentation area for recommended tire size, inflation pressures, and load ratings.
- Consult the owner’s manual or OEM specifications for the exact tire size and performance requirements for front and rear axles.
- Verify the spare tire size as well, since many RVs carry a spare that matches operating tires, though it’s not guaranteed.
Conclusion: With the exact tire size identified, you can select replacements that match the OEM load and speed requirements, keeping your RV safe and road-ready.
Summary
Your RV tire size is printed on the tire sidewall and on the vehicle placard. Decode the size by understanding width, aspect ratio, construction, wheel diameter, and whether the tire is P-, LT-, or ST-type. Replacement tires should match the OEM load index and speed rating, and sizes vary widely across RV classes—from compact trailers to heavy Class A motorhomes. Always verify with multiple sources: sidewall markings, placards, and the owner’s manual.
What does 4.80 mean on a trailer tire?
The “4.80” represents the tire's width in inches. In this case, the tire is 4.8 inches wide. The next digit represents the wheel size the tire will fit. This tire is meant for trailer wheels that are 8 inches in diameter.
How do I find my RV tire size?
Proper RV tire sizes are printed in your owner's manual and also on the side of your current tires. The tire size is listed as ST225/75D16, for example. Let's break this down. Your owner's manual may have a couple different acceptable sizes listed.
Are RV tires the same as regular tires?
RV tires are designed with thicker sidewalls and a narrower tread which allows them to carry considerably more weight than the tires you'd put on your SUV. Car tires simply cannot support the weight of your RV and if used on a travel trailer would be more prone to blowing out.
Is a 275 tire the same as a 33?
No, a "275 tire" is not the same as a "33-inch tire" because the numbers represent different measurements in a tire's size. However, a specific metric size, such as a 275/60R20, can be nearly equivalent to a 33-inch diameter tire. The term "33" is a common, non-metric measurement for a tire's approximate overall diameter.
Tire size explained
- Metric size (e.g., 275/60R20): This is a precise measurement with three parts:
- 275: The width of the tire in millimeters.
- 60: The aspect ratio, which is the height of the sidewall as a percentage of the width (60% of 275mm).
- R20: The radial construction and the diameter of the wheel in inches.
- Non-metric size (e.g., 33x12.5R20): This is a common, more direct way to refer to a tire's approximate overall diameter:
- 33: The approximate total height of the tire in inches.
- 12.5: The width of the tire in inches.
- R20: The radial construction and the diameter of the wheel in inches.
When they are similar
- A 275/60R20 tire is a close equivalent to a 33-inch tire, with a total diameter of approximately 33 inches.
- Other metric sizes, like a 285/75R16, also result in a diameter close to 33 inches.
Why it matters
- Compatibility: Always check the exact metric size of a tire to ensure it will fit your vehicle and is compatible with your suspension and wheel size.
- Speedometer accuracy: Changing your tire diameter significantly can cause your speedometer to be inaccurate. For example, larger tires will make you appear to be driving faster than you actually are.
