285/35R21 vs 295/35R21
Side-by-side comparison of overall diameter, sidewall height, speedometer error, and ride-height change.
Safe to swap — Diameter difference is under 1.5% — within normal tolerance.
To scale
285/35R21
- Section width
- 285 mm
- Aspect ratio
- 35%
- Rim diameter
- 21"
- Sidewall
- 99.8 mm
- Overall diameter
- 732.9 mm
- Circumference
- 2302 mm
- Revs / mile
- 699
- Revs / km
- 434
295/35R21
- Section width
- 295 mm
- Aspect ratio
- 35%
- Rim diameter
- 21"
- Sidewall
- 103.3 mm
- Overall diameter
- 739.9 mm
- Circumference
- 2324 mm
- Revs / mile
- 692
- Revs / km
- 430
Difference
- Overall diameter
- +7.0 mm (+0.96%)
- Sidewall height
- +3.5 mm
- Tread width
- +10 mm
- Ride height (axle)
- +3.5 mm
- Speedometer error
- +0.96%
- At indicated 60 mph
- actual 60.6 mph
- At indicated 100 km/h
- actual 101.0 km/h
Will 295/35R21 fit instead of 285/35R21?
The overall diameter changes by 0.96%. Most manufacturers consider a swap acceptable when the difference stays under 3% — beyond that, you may see speedometer error, ABS/TPMS warnings, or wheel-well clearance problems. This page only covers the math; your vehicle's wheel arches, suspension geometry, and load rating still matter.
What the numbers mean
- Overall diameter — outside-to-outside height of the tire. Affects ride height, gearing, and speedometer calibration.
- Sidewall height — rubber from rim edge to tread. Lower sidewall gives sharper steering response but a harsher ride.
- Speedometer error — how far off your indicated speed will be after the swap. Positive means the speedo under-reads (actual speed is higher than shown).