How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

-0.51%

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

-0.51%

Absolute Difference

-0.13"

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
3029.8-0.2
4039.8-0.2
5049.7-0.3
6059.7-0.3
7069.6-0.4
8079.6-0.4
Tire 1Dia. 25.46 ″Rim 17 ″4.23 ″Width 8.46 ″Revs/Mile 792.0Circum. 80.0″Tire 2Dia. 25.33 ″Rim 17 ″4.16 ″Width 9.25 ″Revs/Mile 796.3Circum. 79.6″
Tire 1
Specification
Tire 2
25.46"
Diameter
25.33"
8.46"
Width
9.25"
4.23"
Sidewall
4.16"
79.999"
Circum.
79.566"
792
Revs/Mile
796.3

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