Tire size comparison
185/65R14 vs 175/65R14
175/65R14 is −2.2% shorter than 185/65R14: 23.0 in vs 23.5 in (−0.51 in), and 0.4 in narrower. With 175/65R14 on a vehicle set up for 185/65R14, the speedometer shows 60 mph at an actual 58.7 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 (175/65R14 instead of 185/65R14) · 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
185/65R14 vs 175/65R14: full comparison
| 185/65R14 | 175/65R14 | Difference | |
|---|---|---|---|
| Overall diameter | 23.47 in | 22.96 in | −0.51 in (−2.2%) |
| Width | 7.28 in | 6.89 in | −0.39 in (−5.4%) |
| Sidewall height | 4.73 in | 4.48 in | −0.26 in |
| Circumference | 73.7 in | 72.1 in | −1.6 in |
| Revs per mile (nominal) | 859 | 879 | +19 |
| Wheel diameter | 14 in | 14 in | ±0 in |
| Diameter in mm | 596 | 583 | −13 mm |
Speedometer difference
Your speedometer is calibrated for 185/65R14. Fitted with 175/65R14, the actual speed is the reading × 22.96 ÷ 23.47.
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 19.6 mph | −0.4 mph |
| 30 mph | 29.3 mph | −0.7 mph |
| 45 mph | 44.0 mph | −1.0 mph |
| 55 mph | 53.8 mph | −1.2 mph |
| 60 mph | 58.7 mph | −1.3 mph |
| 70 mph | 68.5 mph | −1.5 mph |
| 80 mph | 78.3 mph | −1.7 mph |
Real tires: published diameters
185/65R14: 23.3–23.5 in published by 4 makers; 175/65R14: 22.9–23.1 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: 185/65R14 · 175/65R14
Related comparisons
FAQ
Which is bigger, 185/65R14 or 175/65R14?
175/65R14 is −2.2% shorter than 185/65R14: 23.0 in vs 23.5 in (−0.51 in).
How much will my speedometer be off with 175/65R14 instead of 185/65R14?
The speedometer is calibrated for 185/65R14. With 175/65R14 it shows 60 mph when you are doing 58.7 mph, and 70 mph at 68.5 mph (−2.2%). Your speedometer also has its own factory tolerance.
Can I replace 185/65R14 with 175/65R14?
The diameter difference is −2.2%. 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.