How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

-0.31%

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

-0.31%

Absolute Difference

-0.1"

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
2019.9-0.1
3029.9-0.1
4039.9-0.1
5049.8-0.2
6059.8-0.2
7069.8-0.2
8079.8-0.2
Tire 1Dia. 32.71 ″Rim 17 ″7.85 ″Width 11.22 ″Revs/Mile 616.6Circum. 102.8″Tire 2Dia. 32.61 ″Rim 17 ″7.81 ″Width 12.01 ″Revs/Mile 618.5Circum. 102.4″
Tire 1
Specification
Tire 2
32.71"
Diameter
32.61"
11.22"
Width
12.01"
7.85"
Sidewall
7.81"
102.757"
Circum.
102.448"
616.6
Revs/Mile
618.5

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