How it works

TireFlows

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

Tire 1
/R
Tire 2
/R

Result

Diameter Difference

-3.01%

Safety Rating

Caution

Slightly exceeds the common 3% guideline. Monitor vehicle behavior.

The 3% rule is a common reference — not vehicle-specific advice. How it works

Speedometer Error

-3.01%

Absolute Difference

-0.87"

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
2019.4-0.6
3029.1-0.9
4038.8-1.2
5048.5-1.5
6058.2-1.8
7067.9-2.1
8077.6-2.4
Tire 1Dia. 28.91 ″Rim 17 ″5.95 ″Width 10.83 ″Revs/Mile 697.6Circum. 90.8″Tire 2Dia. 28.04 ″Rim 17 ″5.52 ″Width 10.04 ″Revs/Mile 719.2Circum. 88.1″
Tire 1
Specification
Tire 2
28.91"
Diameter
28.04"
10.83"
Width
10.04"
5.95"
Sidewall
5.52"
90.822"
Circum.
88.101"
697.6
Revs/Mile
719.2

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