Tire size comparison
205/45R16 vs 205/50R16
205/50R16 is +3.5% taller than 205/45R16: 24.1 in vs 23.3 in (+0.81 in), and the same width. With 205/50R16 on a vehicle set up for 205/45R16, the speedometer shows 60 mph at an actual 62.1 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 (205/50R16 instead of 205/45R16) · 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
205/45R16 vs 205/50R16: full comparison
| 205/45R16 | 205/50R16 | Difference | |
|---|---|---|---|
| Overall diameter | 23.26 in | 24.07 in | +0.81 in (+3.5%) |
| Width | 8.07 in | 8.07 in | ±0.00 in (±0.0%) |
| Sidewall height | 3.63 in | 4.04 in | +0.40 in |
| Circumference | 73.1 in | 75.6 in | +2.5 in |
| Revs per mile (nominal) | 867 | 838 | −29 |
| Wheel diameter | 16 in | 16 in | ±0 in |
| Diameter in mm | 591 | 611 | +20 mm |
Speedometer difference
Your speedometer is calibrated for 205/45R16. Fitted with 205/50R16, the actual speed is the reading × 24.07 ÷ 23.26.
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 20.7 mph | +0.7 mph |
| 30 mph | 31.0 mph | +1.0 mph |
| 45 mph | 46.6 mph | +1.6 mph |
| 55 mph | 56.9 mph | +1.9 mph |
| 60 mph | 62.1 mph | +2.1 mph |
| 70 mph | 72.4 mph | +2.4 mph |
| 80 mph | 82.8 mph | +2.8 mph |
Real tires: published diameters
205/45R16: 23.2–23.35 in published by 3 makers; 205/50R16: 23.9–24.3 in published by 5 makers. Calculated figures assume a nominal tire; the exact difference between two specific tires depends on their models.
More about each size: 205/45R16 · 205/50R16
Related comparisons
FAQ
Which is bigger, 205/45R16 or 205/50R16?
205/50R16 is +3.5% taller than 205/45R16: 24.1 in vs 23.3 in (+0.81 in).
How much will my speedometer be off with 205/50R16 instead of 205/45R16?
The speedometer is calibrated for 205/45R16. With 205/50R16 it shows 60 mph when you are doing 62.1 mph, and 70 mph at 72.4 mph (+3.5%). Your speedometer also has its own factory tolerance.
Can I replace 205/45R16 with 205/50R16?
The diameter difference is +3.5%. 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.