Tire size comparison
215/40R17 vs 205/40R17
205/40R17 is −1.3% shorter than 215/40R17: 23.5 in vs 23.8 in (−0.31 in), and 0.4 in narrower. With 205/40R17 on a vehicle set up for 215/40R17, the speedometer shows 60 mph at an actual 59.2 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 (205/40R17 instead of 215/40R17) · 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
215/40R17 vs 205/40R17: full comparison
| 215/40R17 | 205/40R17 | Difference | |
|---|---|---|---|
| Overall diameter | 23.77 in | 23.46 in | −0.31 in (−1.3%) |
| Width | 8.46 in | 8.07 in | −0.39 in (−4.7%) |
| Sidewall height | 3.39 in | 3.23 in | −0.16 in |
| Circumference | 74.7 in | 73.7 in | −1.0 in |
| Revs per mile (nominal) | 848 | 860 | +11 |
| Wheel diameter | 17 in | 17 in | ±0 in |
| Diameter in mm | 604 | 596 | −8 mm |
Speedometer difference
Your speedometer is calibrated for 215/40R17. Fitted with 205/40R17, the actual speed is the reading × 23.46 ÷ 23.77.
| 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 | 54.3 mph | −0.7 mph |
| 60 mph | 59.2 mph | −0.8 mph |
| 70 mph | 69.1 mph | −0.9 mph |
| 80 mph | 78.9 mph | −1.1 mph |
Real tires: published diameters
215/40R17: 23.8–23.9 in published by 3 makers; 205/40R17: 23.4–23.54 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: 215/40R17 · 205/40R17
Related comparisons
FAQ
Which is bigger, 215/40R17 or 205/40R17?
205/40R17 is −1.3% shorter than 215/40R17: 23.5 in vs 23.8 in (−0.31 in).
How much will my speedometer be off with 205/40R17 instead of 215/40R17?
The speedometer is calibrated for 215/40R17. With 205/40R17 it shows 60 mph when you are doing 59.2 mph, and 70 mph at 69.1 mph (−1.3%). Your speedometer also has its own factory tolerance.
Can I replace 215/40R17 with 205/40R17?
The diameter difference is −1.3%. 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.