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

-0.06"

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
3029.9-0.1
4039.9-0.1
5049.9-0.1
6059.9-0.1
7069.9-0.1
8079.9-0.1
Tire 1Dia. 33.16 ″Rim 18 ″7.58 ″Width 10.83 ″Revs/Mile 608.3Circum. 104.2″Tire 2Dia. 33.10 ″Rim 18 ″7.55 ″Width 11.61 ″Revs/Mile 609.3Circum. 104.0″
Tire 1
Specification
Tire 2
33.16"
Diameter
33.1"
10.83"
Width
11.61"
7.58"
Sidewall
7.55"
104.167"
Circum.
103.982"
608.3
Revs/Mile
609.3

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