How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

-0.03%

Safety Rating

Safe

Within the recommended 3% safety margin.

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

Speedometer Error

-0.03%

Absolute Difference

-0.01"

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
20200
30300
40400
50500
60600
70700
80800
Tire 1Dia. 31.07 ″Rim 17 ″7.04 ″Width 10.83 ″Revs/Mile 649.0Circum. 97.6″Tire 2Dia. 31.06 ″Rim 17 ″7.03 ″Width 10.04 ″Revs/Mile 649.4Circum. 97.6″
Tire 1
Specification
Tire 2
31.07"
Diameter
31.06"
10.83"
Width
10.04"
7.04"
Sidewall
7.03"
97.624"
Circum.
97.563"
649
Revs/Mile
649.4

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