How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

1.85%

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

1.85%

Absolute Difference

0.51"

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
2020.4+0.4
3030.6+0.6
4040.7+0.7
5050.9+0.9
6061.1+1.1
7071.3+1.3
8081.5+1.5
Tire 1Dia. 27.52 ″Rim 16 ″5.76 ″Width 8.86 ″Revs/Mile 733.0Circum. 86.4″Tire 2Dia. 28.03 ″Rim 16 ″6.01 ″Width 9.25 ″Revs/Mile 719.6Circum. 88.1″
Tire 1
Specification
Tire 2
27.52"
Diameter
28.03"
8.86"
Width
9.25"
5.76"
Sidewall
6.01"
86.443"
Circum.
88.051"
733
Revs/Mile
719.6

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