Tire size comparison
285/75R16 vs 33x12.50R16
33x12.50R16 is +0.5% taller than 285/75R16: 33.0 in vs 32.8 in (+0.17 in), and 1.3 in wider. With 33x12.50R16 on a vehicle set up for 285/75R16, the speedometer shows 60 mph at an actual 60.3 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 (33x12.50R16 instead of 285/75R16) · 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
285/75R16 vs 33x12.50R16: full comparison
| 285/75R16 | 33x12.50R16 | Difference | |
|---|---|---|---|
| Overall diameter | 32.83 in | 33.00 in | +0.17 in (+0.5%) |
| Width | 11.22 in | 12.50 in | +1.28 in (+11.4%) |
| Sidewall height | 8.42 in | 8.50 in | +0.08 in |
| Circumference | 103.1 in | 103.7 in | +0.5 in |
| Revs per mile (nominal) | 614 | 611 | −3 |
| Wheel diameter | 16 in | 16 in | ±0 in |
| Diameter in mm | 834 | 838 | +4 mm |
Speedometer difference
Your speedometer is calibrated for 285/75R16. Fitted with 33x12.50R16, the actual speed is the reading × 33.00 ÷ 32.83.
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 20.1 mph | +0.1 mph |
| 30 mph | 30.2 mph | +0.2 mph |
| 45 mph | 45.2 mph | +0.2 mph |
| 55 mph | 55.3 mph | +0.3 mph |
| 60 mph | 60.3 mph | +0.3 mph |
| 70 mph | 70.4 mph | +0.4 mph |
| 80 mph | 80.4 mph | +0.4 mph |
Real tires: published diameters
285/75R16: 32.7–33.2 in published by 5 makers; 33x12.50R16: not in the data books we use. Calculated figures assume a nominal tire; the exact difference between two specific tires depends on their models.
More about each size: 285/75R16 · 33x12.50R16
Related comparisons
FAQ
Which is bigger, 285/75R16 or 33x12.50R16?
33x12.50R16 is +0.5% taller than 285/75R16: 33.0 in vs 32.8 in (+0.17 in).
How much will my speedometer be off with 33x12.50R16 instead of 285/75R16?
The speedometer is calibrated for 285/75R16. With 33x12.50R16 it shows 60 mph when you are doing 60.3 mph, and 70 mph at 70.4 mph (+0.5%). Your speedometer also has its own factory tolerance.
Can I replace 285/75R16 with 33x12.50R16?
The diameter difference is +0.5%. 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.