325/35R20 Tire Size
325/35R20 diameter, sidewall, revolutions per mile, and plus-sizing options.
The 325/35R20 tire size breaks down as: 325 mm section width, 35% aspect ratio, and a 20-inch rim. Below are its real, calculated dimensions.
325/35R20 Calculated Dimensions
| Metric | Value |
|---|---|
| Overall diameter | 29.0 in (736 mm) |
| Sidewall height | 4.5 in (114 mm) |
| Circumference | 91.0 in (2311 mm) |
| Revolutions per mile | 696 |
Typical Fitment
325/35R20 is most often found on performance trucks. Always confirm against the door-jamb placard or owner manual before fitting.
Plus-Sizing Alternatives
These sizes keep the overall diameter close to 325/35R20, so speedometer and gearing stay near stock:
| Size | Diameter | Diameter change |
|---|---|---|
| 335/35R20 | 29.23 in | +1.0% |
| 335/30R21 | 28.91 in | -0.1% |
| 345/25R22 | 28.79 in | -0.6% |
Speedometer Note
If you fit a 335/35R20 instead of 325/35R20, the diameter changes by +1.0%. A taller tire makes your speedometer read low — at a true 60 mph it would show roughly 59 mph. A shorter tire has the opposite effect, so the gauge reads high.
Use the tire calculator to compare 325/35R20 against any other size and see the exact diameter and speedometer difference.
Frequently Asked Questions
What does 325/35R20 mean?
325/35R20 means a 325 mm wide tire with a 35% sidewall aspect ratio mounted on a 20-inch rim. The aspect ratio is the sidewall height as a percentage of the width.
Can I plus-size from 325/35R20?
Yes, as long as the replacement keeps the overall diameter close to stock so the speedometer stays accurate. Common plus-size moves from 325/35R20 are 335/35R20, 335/30R21, 345/25R22.
Will 325/35R20 affect my speedometer?
Only if it differs in diameter from your original size. A taller tire reads low; a shorter tire reads high. Compare the two sizes with the calculator to find the percentage.