How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

0.84%

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

0.84%

Absolute Difference

0.22"

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
2020.2+0.2
3030.3+0.3
4040.3+0.3
5050.4+0.4
6060.5+0.5
7070.6+0.6
8080.7+0.7
Tire 1Dia. 26.30 ″Rim 15 ″5.65 ″Width 8.07 ″Revs/Mile 766.9Circum. 82.6″Tire 2Dia. 26.52 ″Rim 15 ″5.76 ″Width 8.86 ″Revs/Mile 760.6Circum. 83.3″
Tire 1
Specification
Tire 2
26.3"
Diameter
26.52"
8.07"
Width
8.86"
5.65"
Sidewall
5.76"
82.621"
Circum.
83.302"
766.9
Revs/Mile
760.6

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