How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

-1.06%

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

-1.06%

Absolute Difference

-0.26"

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
2019.8-0.2
3029.7-0.3
4039.6-0.4
5049.5-0.5
6059.4-0.6
7069.3-0.7
8079.1-0.9
Tire 1Dia. 24.47 ″Rim 15 ″4.73 ″Width 7.28 ″Revs/Mile 824.2Circum. 76.9″Tire 2Dia. 24.21 ″Rim 15 ″4.61 ″Width 7.68 ″Revs/Mile 833.0Circum. 76.1″
Tire 1
Specification
Tire 2
24.47"
Diameter
24.21"
7.28"
Width
7.68"
4.73"
Sidewall
4.61"
76.87"
Circum.
76.066"
824.2
Revs/Mile
833

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