285/75R16 vs 305/70R16: full comparison
| Measurement | 285/75R16 | 305/70R16 | Difference |
|---|---|---|---|
| Diameter | 32.83 in | 32.81 in | −0.02 in−0.1% |
| Section width | 11.22 in | 12.01 in | +0.79 in+7.0% |
| Sidewall height | 8.42 in | 8.41 in | −0.01 in−0.1% |
| Circumference | 103.14 in | 103.08 in | −0.06 in−0.1% |
| Revs per mile | 614 | 615 | 0+0.1% |
Speedometer: indicated vs actual speed
With 305/70R16 fitted where 285/75R16 was the stock/calibrated size:
| Speedometer shows | Actual speed | Difference |
|---|---|---|
| 20 mph | 20.0 mph | 0.0 mph |
| 30 mph | 30.0 mph | 0.0 mph |
| 40 mph | 40.0 mph | 0.0 mph |
| 50 mph | 50.0 mph | 0.0 mph |
| 55 mph | 55.0 mph | 0.0 mph |
| 60 mph | 60.0 mph | 0.0 mph |
| 65 mph | 65.0 mph | 0.0 mph |
| 70 mph | 70.0 mph | 0.0 mph |
| 75 mph | 75.0 mph | 0.0 mph |
| 80 mph | 80.0 mph | 0.0 mph |
Recalculate for a gear ratio change too →
Will 305/70R16 fit where 285/75R16 was?
285/75R16 and 305/70R16 are essentially the same overall height (−0.1%), so this is usually a straightforward swap as far as fitment goes -- the main thing to check is wheel width and offset, not diameter.
Related tire size comparisons
- 265/75R16 vs 285/75R16
- 255/85R16 vs 285/75R16
- 285/75R16 vs 315/75R16
- 245/75R16 vs 285/75R16
- 285/70R17 vs 285/75R16
More tire tools
- Tire size comparison tool: compare any two sizes yourself, including flotation sizes.
- Tire size calculator: full dimensions of one size, plus every equivalent size within 3%.
- Speedometer calculator: true speed after a tire or gear ratio change.
Frequently asked questions
How much bigger is 305/70R16 than 285/75R16?
305/70R16 is 0.02 in shorter in overall diameter (−0.1%) and 0.79 in wider in section width (+7.0%) than 285/75R16.
Will 305/70R16 fit in place of 285/75R16?
285/75R16 and 305/70R16 are essentially the same overall height (−0.1%), so this is usually a straightforward swap as far as fitment goes -- the main thing to check is wheel width and offset, not diameter.
Does swapping to 305/70R16 affect my speedometer?
Since the two sizes are almost the same height, your speedometer will read essentially correctly either way. That small a difference is within the ±3% most shops treat as close enough not to recalibrate.
Does 305/70R16 change the ride height?
Yes -- half the diameter difference shows up at the axle, so 305/70R16 changes ride height by about 0.01 in lower compared with 285/75R16.
Do 285/75R16 and 305/70R16 use the same wheel (rim) diameter?
Yes -- both fit a 16 inch wheel, so only the tire itself changes, not the wheel.