How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

-1.4%

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

-1.4%

Absolute Difference

-0.45"

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
2019.7-0.3
3029.6-0.4
4039.4-0.6
5049.3-0.7
6059.2-0.8
7069-1
8078.9-1.1
Tire 1Dia. 32.06 ″Rim 17 ″7.53 ″Width 10.04 ″Revs/Mile 629.1Circum. 100.7″Tire 2Dia. 31.61 ″Rim 17 ″7.30 ″Width 10.43 ″Revs/Mile 638.1Circum. 99.3″
Tire 1
Specification
Tire 2
32.06"
Diameter
31.61"
10.04"
Width
10.43"
7.53"
Sidewall
7.3"
100.716"
Circum.
99.294"
629.1
Revs/Mile
638.1

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