How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

-0.06%

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

-0.06%

Absolute Difference

-0.02"

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
8079.9-0.1
Tire 1Dia. 31.61 ″Rim 17 ″7.30 ″Width 10.43 ″Revs/Mile 638.1Circum. 99.3″Tire 2Dia. 31.59 ″Rim 17 ″7.29 ″Width 11.22 ″Revs/Mile 638.5Circum. 99.2″
Tire 1
Specification
Tire 2
31.61"
Diameter
31.59"
10.43"
Width
11.22"
7.3"
Sidewall
7.29"
99.294"
Circum.
99.232"
638.1
Revs/Mile
638.5

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