How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

-0.08%

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

-0.08%

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
7069.9-0.1
8079.9-0.1
Tire 1Dia. 24.88 ″Rim 16 ″4.44 ″Width 8.07 ″Revs/Mile 810.7Circum. 78.2″Tire 2Dia. 24.86 ″Rim 16 ″4.43 ″Width 8.86 ″Revs/Mile 811.3Circum. 78.1″
Tire 1
Specification
Tire 2
24.88"
Diameter
24.86"
8.07"
Width
8.86"
4.44"
Sidewall
4.43"
78.156"
Circum.
78.095"
810.7
Revs/Mile
811.3

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