How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

-1.87%

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

-1.87%

Absolute Difference

-0.48"

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
2019.6-0.4
3029.4-0.6
4039.3-0.7
5049.1-0.9
6058.9-1.1
7068.7-1.3
8078.5-1.5
Tire 1Dia. 25.69 ″Rim 16 ″4.84 ″Width 8.07 ″Revs/Mile 785.2Circum. 80.7″Tire 2Dia. 25.21 ″Rim 16 ″4.61 ″Width 7.68 ″Revs/Mile 799.9Circum. 79.2″
Tire 1
Specification
Tire 2
25.69"
Diameter
25.21"
8.07"
Width
7.68"
4.84"
Sidewall
4.61"
80.692"
Circum.
79.208"
785.2
Revs/Mile
799.9

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