Automotive Smog Check Tips
The SPEED Rating is "S", so it's not wise to drive these Tires
over 112 MPH with continuity...The last digits are "17".
It denotes the Diameter of the Rim, not the Diameter of the Tire.
Letter Maximum Rated Speed
L 75 Miles Per Hour
M 81 MPH
N 87 MPH
P 93 MPH
Q 99 MPH
R 106 MPH
S 112 MPH
T 118 MPH
U 124 MPH
H 130 MPH
V 149 MPH
W 168 MPH
Y 186 MPH
Z Open-ended *
The exact speed rating for a particular Z- rated tire is determined by
the tire manufacturer and may vary according to size. For example, not
all Brand X Z tires are rated at 170 mph, even though one size may be
capable of all speeds.
Automotive Principles Technology - James D. Halderman
https://www.sokule.com/blog/cbarkwell