Tire Size Designation

How to read a tire sidewall code:

Tire Construction
R = Radial construction
D = Diagonal Bias
B = Belted Bias

Load Index

Index	Pounds	Kilograms		Index	Pounds	Kilograms
71	761	345		91	1,356	615
72	783	355		92	1,389	630
73	805	365		93	1,433	650
74	827	375		94	1,477	670
75	853	387		95	1,521	690
76	882	400		96	1,565	710
77	908	412		97	1,609	730
78	937	425		98	1,653	750
79	963	437		99	1,709	775
80	992	450		100	1,764	800
81	1,019	462		101	1,819	825
82	1,047	475		102	1,874	850
83	1,074	487		103	1,929	875
84	1,102	500		104	1,984	900
85	1,135	515		105	2,039	925
86	1,168	530		106	2,094	950
87	1,201	545		107	2,149	975
88	1,235	560		108	2,205	1,000
89	1,279	580		109	2,271	1,030
90	1,323	600		110	2,337	1,060

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Speed Rating

Code	Miles/hour	Km/hour	Typical Use
N	87	140	Spare Tires
P	93	150
Q	99	160	Winter
R	106	170	Light Trucks
S	112	180
T	118	190
U	124	200
H	130	210	Sport Sedans
V	149	240	Sport Cars
Z	149+	240+	Sport Cars
W	168	270	Exotic Sport Cars
Y	186	300	Exotic Sport Cars

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Tread Wear

The simplest way to check tread is to place a penny into the tread (Lincoln's head first). If the top of his head remains visible, the tire needs replacing.