Tire size comparison
205/75R15 vs 225/75R15
225/75R15 is +4.4% taller than 205/75R15: 28.3 in vs 27.1 in (+1.18 in), and 0.8 in wider. With 225/75R15 on a vehicle set up for 205/75R15, the speedometer shows 60 mph at an actual 62.6 mph. That is more than the ±3% difference many shops use as a rule of thumb, so check carefully before switching.
Set up for: going bigger (225/75R15 instead of 205/75R15) · Different situation?
Your current size
e.g. 265/70R17, 2657017 or 33x12.50R20
Where do I find my size?
It's on the tire sidewall, e.g. P265/70R17 115T, and on the tire placard sticker on the driver's door jamb (also in the owner's manual). The placard shows the size the vehicle came with; the sidewall shows what is fitted now. If they differ, use the placard as your starting point. Digits are enough here: 2657017 or 33125020.
Size you're considering
205/75R15 vs 225/75R15: full comparison
| 205/75R15 | 225/75R15 | Difference | |
|---|---|---|---|
| Overall diameter | 27.11 in | 28.29 in | +1.18 in (+4.4%) |
| Width | 8.07 in | 8.86 in | +0.79 in (+9.8%) |
| Sidewall height | 6.05 in | 6.64 in | +0.59 in |
| Circumference | 85.2 in | 88.9 in | +3.7 in |
| Revs per mile (nominal) | 744 | 713 | −31 |
| Wheel diameter | 15 in | 15 in | ±0 in |
| Diameter in mm | 688 | 718 | +30 mm |
Speedometer difference
Your speedometer is calibrated for 205/75R15. Fitted with 225/75R15, the actual speed is the reading × 28.29 ÷ 27.11.
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 20.9 mph | +0.9 mph |
| 30 mph | 31.3 mph | +1.3 mph |
| 45 mph | 47.0 mph | +2.0 mph |
| 55 mph | 57.4 mph | +2.4 mph |
| 60 mph | 62.6 mph | +2.6 mph |
| 70 mph | 73.1 mph | +3.1 mph |
| 80 mph | 83.5 mph | +3.5 mph |
Real tires: published diameters
205/75R15: 27–27.1 in published by 2 makers; 225/75R15: 28.2–28.3 in published by 3 makers. Calculated figures assume a nominal tire; the exact difference between two specific tires depends on their models.
More about each size: 205/75R15 · 225/75R15
Related comparisons
FAQ
Which is bigger, 205/75R15 or 225/75R15?
225/75R15 is +4.4% taller than 205/75R15: 28.3 in vs 27.1 in (+1.18 in).
How much will my speedometer be off with 225/75R15 instead of 205/75R15?
The speedometer is calibrated for 205/75R15. With 225/75R15 it shows 60 mph when you are doing 62.6 mph, and 70 mph at 73.1 mph (+4.4%). Your speedometer also has its own factory tolerance.
Can I replace 205/75R15 with 225/75R15?
The diameter difference is +4.4%. Whether it fits depends on things this calculation can't see: wheel width and offset, clearance at full lock and over bumps, load index and speed rating, and your vehicle maker's approval. Check your door-jamb placard and owner's manual and ask a tire professional.