295/25R21 Tire Size
295/25R21 diameter, sidewall, revolutions per mile, and plus-sizing options.
The 295/25R21 tire size breaks down as: 295 mm section width, 25% aspect ratio, and a 21-inch rim. Below are its real, calculated dimensions.
295/25R21 Calculated Dimensions
| Metric | Value |
|---|---|
| Overall diameter | 26.8 in (681 mm) |
| Sidewall height | 2.9 in (74 mm) |
| Circumference | 84.2 in (2139 mm) |
| Revolutions per mile | 752 |
Typical Fitment
295/25R21 is most often found on exotic performance cars. Always confirm against the door-jamb placard or owner manual before fitting.
Plus-Sizing Alternatives
These sizes keep the overall diameter close to 295/25R21, so speedometer and gearing stay near stock:
| Size | Diameter | Diameter change |
|---|---|---|
| 305/25R21 | 27.00 in | +0.7% |
| 305/20R22 | 26.80 in | -0.0% |
| 315/15R23 | 26.72 in | -0.3% |
Speedometer Note
If you fit a 305/25R21 instead of 295/25R21, the diameter changes by +0.7%. A taller tire makes your speedometer read low — at a true 60 mph it would show roughly 60 mph. A shorter tire has the opposite effect, so the gauge reads high.
Use the tire calculator to compare 295/25R21 against any other size and see the exact diameter and speedometer difference.
Frequently Asked Questions
What does 295/25R21 mean?
295/25R21 means a 295 mm wide tire with a 25% sidewall aspect ratio mounted on a 21-inch rim. The aspect ratio is the sidewall height as a percentage of the width.
Can I plus-size from 295/25R21?
Yes, as long as the replacement keeps the overall diameter close to stock so the speedometer stays accurate. Common plus-size moves from 295/25R21 are 305/25R21, 305/20R22, 315/15R23.
Will 295/25R21 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.