Tire size comparison
185/55R15 vs 195/55R15
195/55R15 is +1.9% taller than 185/55R15: 23.4 in vs 23.0 in (+0.43 in), and 0.4 in wider. With 195/55R15 on a vehicle set up for 185/55R15, the speedometer shows 60 mph at an actual 61.1 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 (195/55R15 instead of 185/55R15) · 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
185/55R15 vs 195/55R15: full comparison
| 185/55R15 | 195/55R15 | Difference | |
|---|---|---|---|
| Overall diameter | 23.01 in | 23.44 in | +0.43 in (+1.9%) |
| Width | 7.28 in | 7.68 in | +0.39 in (+5.4%) |
| Sidewall height | 4.01 in | 4.22 in | +0.22 in |
| Circumference | 72.3 in | 73.7 in | +1.4 in |
| Revs per mile (nominal) | 876 | 860 | −16 |
| Wheel diameter | 15 in | 15 in | ±0 in |
| Diameter in mm | 584 | 595 | +11 mm |
Speedometer difference
Your speedometer is calibrated for 185/55R15. Fitted with 195/55R15, the actual speed is the reading × 23.44 ÷ 23.01.
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 20.4 mph | +0.4 mph |
| 30 mph | 30.6 mph | +0.6 mph |
| 45 mph | 45.8 mph | +0.8 mph |
| 55 mph | 56.0 mph | +1.0 mph |
| 60 mph | 61.1 mph | +1.1 mph |
| 70 mph | 71.3 mph | +1.3 mph |
| 80 mph | 81.5 mph | +1.5 mph |
Real tires: published diameters
185/55R15: 22.9–23.1 in published by 4 makers; 195/55R15: 23.3–23.5 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: 185/55R15 · 195/55R15
Related comparisons
FAQ
Which is bigger, 185/55R15 or 195/55R15?
195/55R15 is +1.9% taller than 185/55R15: 23.4 in vs 23.0 in (+0.43 in).
How much will my speedometer be off with 195/55R15 instead of 185/55R15?
The speedometer is calibrated for 185/55R15. With 195/55R15 it shows 60 mph when you are doing 61.1 mph, and 70 mph at 71.3 mph (+1.9%). Your speedometer also has its own factory tolerance.
Can I replace 185/55R15 with 195/55R15?
The diameter difference is +1.9%. 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.