How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

-0.47%

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

-0.47%

Absolute Difference

-0.14"

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
3029.9-0.1
4039.8-0.2
5049.8-0.2
6059.7-0.3
7069.7-0.3
8079.6-0.4
Tire 1Dia. 29.54 ″Rim 17 ″6.27 ″Width 9.65 ″Revs/Mile 682.8Circum. 92.8″Tire 2Dia. 29.40 ″Rim 17 ″6.20 ″Width 8.86 ″Revs/Mile 686.0Circum. 92.4″
Tire 1
Specification
Tire 2
29.54"
Diameter
29.4"
9.65"
Width
8.86"
6.27"
Sidewall
6.2"
92.801"
Circum.
92.368"
682.8
Revs/Mile
686

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