How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

0.18%

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

0.18%

Absolute Difference

0.05"

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
3030.1+0.1
4040.1+0.1
5050.1+0.1
6060.1+0.1
7070.1+0.1
8080.1+0.1
Tire 1Dia. 27.52 ″Rim 16 ″5.76 ″Width 8.86 ″Revs/Mile 733.0Circum. 86.4″Tire 2Dia. 27.57 ″Rim 16 ″5.79 ″Width 9.65 ″Revs/Mile 731.4Circum. 86.6″
Tire 1
Specification
Tire 2
27.52"
Diameter
27.57"
8.86"
Width
9.65"
5.76"
Sidewall
5.79"
86.443"
Circum.
86.629"
733
Revs/Mile
731.4

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