Tire size comparison
225/45R17 vs 215/45R17
215/45R17 is −1.4% shorter than 225/45R17: 24.6 in vs 25.0 in (−0.35 in), and 0.4 in narrower. With 215/45R17 on a vehicle set up for 225/45R17, the speedometer shows 60 mph at an actual 59.1 mph. That is within the ±3% difference many shops use as a rule of thumb (not a manufacturer or legal limit).
Set up for: checking a replacement size (215/45R17 instead of 225/45R17) · 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
225/45R17 vs 215/45R17: full comparison
| 225/45R17 | 215/45R17 | Difference | |
|---|---|---|---|
| Overall diameter | 24.97 in | 24.62 in | −0.35 in (−1.4%) |
| Width | 8.86 in | 8.46 in | −0.39 in (−4.4%) |
| Sidewall height | 3.99 in | 3.81 in | −0.18 in |
| Circumference | 78.5 in | 77.3 in | −1.1 in |
| Revs per mile (nominal) | 808 | 819 | +12 |
| Wheel diameter | 17 in | 17 in | ±0 in |
| Diameter in mm | 634 | 625 | −9 mm |
Speedometer difference
Your speedometer is calibrated for 225/45R17. Fitted with 215/45R17, the actual speed is the reading × 24.62 ÷ 24.97.
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 19.7 mph | −0.3 mph |
| 30 mph | 29.6 mph | −0.4 mph |
| 45 mph | 44.4 mph | −0.6 mph |
| 55 mph | 54.2 mph | −0.8 mph |
| 60 mph | 59.1 mph | −0.9 mph |
| 70 mph | 69.0 mph | −1.0 mph |
| 80 mph | 78.9 mph | −1.1 mph |
Real tires: published diameters
225/45R17: 24.7–25.2 in published by 6 makers; 215/45R17: 24.4–24.9 in published by 7 makers. Calculated figures assume a nominal tire; the exact difference between two specific tires depends on their models.
More about each size: 225/45R17 · 215/45R17
Related comparisons
FAQ
Which is bigger, 225/45R17 or 215/45R17?
215/45R17 is −1.4% shorter than 225/45R17: 24.6 in vs 25.0 in (−0.35 in).
How much will my speedometer be off with 215/45R17 instead of 225/45R17?
The speedometer is calibrated for 225/45R17. With 215/45R17 it shows 60 mph when you are doing 59.1 mph, and 70 mph at 69.0 mph (−1.4%). Your speedometer also has its own factory tolerance.
Can I replace 225/45R17 with 215/45R17?
The diameter difference is −1.4%. 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.