295/40R15 vs 295/45R15
Comparison of overall diameter, sidewall, speedometer error, and ride-height change between these two tire sizes.
295/40R15
- Section width
- 295 mm
- Aspect ratio
- 40%
- Rim
- 15"
- Sidewall
- 118.0 mm
- Overall diameter
- 617.0 mm
- Revs / mile
- 830
295/45R15
- Section width
- 295 mm
- Aspect ratio
- 45%
- Rim
- 15"
- Sidewall
- 132.8 mm
- Overall diameter
- 646.5 mm
- Revs / mile
- 792
Difference
- Overall diameter
- +29.5 mm (+4.78%)
- Sidewall
- +14.8 mm
- Tread width
- +0 mm
- Ride height (axle)
- +14.8 mm
- Speedometer error
- +4.78%
- At indicated 60 mph
- actual 62.87 mph
Will 295/45R15 fit instead of 295/40R15?
The overall diameter changes by 4.78%. 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 is the outside-to-outside height of the tire. Affects ride height, gearing, and speedometer.
- Sidewall is the height of the rubber from rim to tread. Lower sidewall = sharper steering, harsher ride.
- Speedometer error is the percentage your indicated speed will be off after the swap (positive = speedo reads lower than actual).