How it works

TireFlows

Get diameter, speedometer impact, and alternate sizes — free, no signup.

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

3.48%

Safety Rating

Caution

Slightly exceeds the common 3% guideline. Monitor vehicle behavior.

The 3% rule is a common reference — not vehicle-specific advice. How it works

Speedometer Error

3.48%

Absolute Difference

1.1"

Speedometer

Assumes Tire 1 is what the speedometer is calibrated for. Shows approximate actual speed if you switch to Tire 2.

Reading (mph)Actual (mph)Difference
2020.7+0.7
3031+1
4041.4+1.4
5051.7+1.7
6062.1+2.1
7072.4+2.4
8082.8+2.8
Tire 1Dia. 31.61 ″Rim 17 ″7.30 ″Width 10.43 ″Revs/Mile 638.1Circum. 99.3″Tire 2Dia. 32.71 ″Rim 17 ″7.85 ″Width 11.22 ″Revs/Mile 616.6Circum. 102.8″
Tire 1
Specification
Tire 2
31.61"
Diameter
32.71"
10.43"
Width
11.22"
7.3"
Sidewall
7.85"
99.294"
Circum.
102.757"
638.1
Revs/Mile
616.6

How results are calculated

Tire dimensions are calculated from the metric size format (width / aspect ratio / rim diameter). Diameter, circumference, and revolutions per mile are derived mathematically — no fitment or vehicle data is used.

The 3% rule is a general reference for acceptable diameter difference, not a guarantee. Always check your vehicle manual or consult a tire professional.

How it works