Tire size comparison
285/75R16 vs 315/75R16
315/75R16 is +5.4% taller than 285/75R16: 34.6 in vs 32.8 in (+1.77 in), and 1.2 in wider. With 315/75R16 on a vehicle set up for 285/75R16, the speedometer shows 60 mph at an actual 63.2 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 (315/75R16 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 315/75R16: full comparison
| 285/75R16 | 315/75R16 | Difference | |
|---|---|---|---|
| Overall diameter | 32.83 in | 34.60 in | +1.77 in (+5.4%) |
| Width | 11.22 in | 12.40 in | +1.18 in (+10.5%) |
| Sidewall height | 8.42 in | 9.30 in | +0.89 in |
| Circumference | 103.1 in | 108.7 in | +5.6 in |
| Revs per mile (nominal) | 614 | 583 | −31 |
| Wheel diameter | 16 in | 16 in | ±0 in |
| Diameter in mm | 834 | 879 | +45 mm |
Speedometer difference
Your speedometer is calibrated for 285/75R16. Fitted with 315/75R16, the actual speed is the reading × 34.60 ÷ 32.83.
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 21.1 mph | +1.1 mph |
| 30 mph | 31.6 mph | +1.6 mph |
| 45 mph | 47.4 mph | +2.4 mph |
| 55 mph | 58.0 mph | +3.0 mph |
| 60 mph | 63.2 mph | +3.2 mph |
| 70 mph | 73.8 mph | +3.8 mph |
| 80 mph | 84.3 mph | +4.3 mph |
Real tires: published diameters
285/75R16: 32.7–33.2 in published by 5 makers; 315/75R16: 34.57–34.96 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: 285/75R16 · 315/75R16
Related comparisons
FAQ
Which is bigger, 285/75R16 or 315/75R16?
315/75R16 is +5.4% taller than 285/75R16: 34.6 in vs 32.8 in (+1.77 in).
How much will my speedometer be off with 315/75R16 instead of 285/75R16?
The speedometer is calibrated for 285/75R16. With 315/75R16 it shows 60 mph when you are doing 63.2 mph, and 70 mph at 73.8 mph (+5.4%). Your speedometer also has its own factory tolerance.
Can I replace 285/75R16 with 315/75R16?
The diameter difference is +5.4%. 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.