Tire size comparison
215/45R18 vs 205/60R16
205/60R16 is +0.3% taller than 215/45R18: 25.7 in vs 25.6 in (+0.07 in), and 0.4 in narrower. With 205/60R16 on a vehicle set up for 215/45R18, the speedometer shows 60 mph at an actual 60.2 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 (205/60R16 instead of 215/45R18) · 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
215/45R18 vs 205/60R16: full comparison
| 215/45R18 | 205/60R16 | Difference | |
|---|---|---|---|
| Overall diameter | 25.62 in | 25.69 in | +0.07 in (+0.3%) |
| Width | 8.46 in | 8.07 in | −0.39 in (−4.7%) |
| Sidewall height | 3.81 in | 4.84 in | +1.03 in |
| Circumference | 80.5 in | 80.7 in | +0.2 in |
| Revs per mile (nominal) | 787 | 785 | −2 |
| Wheel diameter | 18 in | 16 in | −2 in |
| Diameter in mm | 651 | 652 | +2 mm |
Speedometer difference
Your speedometer is calibrated for 215/45R18. Fitted with 205/60R16, the actual speed is the reading × 25.69 ÷ 25.62.
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 20.1 mph | +0.1 mph |
| 30 mph | 30.1 mph | +0.1 mph |
| 45 mph | 45.1 mph | +0.1 mph |
| 55 mph | 55.1 mph | +0.1 mph |
| 60 mph | 60.2 mph | +0.2 mph |
| 70 mph | 70.2 mph | +0.2 mph |
| 80 mph | 80.2 mph | +0.2 mph |
Real tires: published diameters
215/45R18: 25.4–25.9 in published by 5 makers; 205/60R16: 25.5–26 in published by 4 makers. Calculated figures assume a nominal tire; the exact difference between two specific tires depends on their models.
More about each size: 215/45R18 · 205/60R16
Related comparisons
FAQ
Which is bigger, 215/45R18 or 205/60R16?
205/60R16 is +0.3% taller than 215/45R18: 25.7 in vs 25.6 in (+0.07 in).
How much will my speedometer be off with 205/60R16 instead of 215/45R18?
The speedometer is calibrated for 215/45R18. With 205/60R16 it shows 60 mph when you are doing 60.2 mph, and 70 mph at 70.2 mph (+0.3%). Your speedometer also has its own factory tolerance.
Can I replace 215/45R18 with 205/60R16?
The diameter difference is +0.3%. 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.