Choosing Tires By Size And Indexes

In order to exemplify, we will use an usual size: 195/65R15. Keep in mind that the tire size for each car is written in the registration.

What is 195/65R15?

195 The tire width measured in mm. It represents the widest section of the tire when correctly mounted. The real width of the tire depends on the width of the wheel on which it is mounted.

65 This number refers to the height of the sidewall. It is the percentage it measures out of the section width.

R Radial. It indicates a radial tire construction, in which the tire's body plies "radiate" out from the imaginary center of the wheel. Radial tires are by far the most popular type of tire today representing over 98% of all tires sold. Alternatives: B - belted construction and D - diagonal construction.

15 Wheel diameter in inches. It is the wheel size that the tire fits on. There's an older type of rims, called TRx,that have a size index of 390. They are not compatible with regular tires.

91 Load index

H Speed rate

VELOCITY INDEX

Velocity index	Maximum speed KM/H
F	80
G	90
J	100
K	110
L	120
M	130
N	140
P	150
Q	160
R	170
S	180
T	190
U	200
H	210
V	240
ZR	OVER 240
W	270
Y	300

WEIGHT INDEX

Weight index	Tire load (kg.)	Weight index	Tire load (kg.)	Weight index	Tire load (kg.)
60	250	96	710	132	2000
61	257	97	730	133	2060
62	265	98	750	134	2120
63	272	99	775	135	2180
64	280	100	800	136	2240
65	290	101	825	137	2300
66	300	102	850	138	2360
67	307	103	875	139	2430
68	315	104	900	140	2500
69	325	105	925	141	2575
70	335	106	950	142	2650
71	345	107	975	143	2725
72	355	108	1000	144	2800
73	365	109	1030	145	2900
74	375	110	1060	146	3000
75	387	111	1090	147	3075
76	400	112	1120	148	3150
77	412	113	1150	149	3250
78	425	114	1180	150	3350
79	437	115	1215	151	3450
80	450	116	1250	152	3550
81	462	117	1285	153	3650
82	475	118	1320	154	3750
83	487	119	1360	155	3875
84	500	120	1400	156	4000
85	515	121	1450	157	4125
86	530	122	1500	158	4250
87	545	123	1550	159	4375
88	560	124	1600	160	4500
89	580	125	1650	161	4625
90	600	126	1700	162	4750
91	615	127	1750	163	4875
92	630	128	1800	164	5000
93	650	129	1850	165	5150
94	670	130	1900
95	690	131	1950

Other Symbols Written On The Tire

M+S      (M&S or M-S) Indicates that the tire can perform well in all seasons. Most winter and all-seasons tires have this index.
*          It indicates a very good performance on snow. This kind of tire does better in winter conditions than the M+S ones. They are the safest winter tires.
DOT      Department Of Transportation. It precedes the maker's logo. In that area you can also find the tire size, the fabrication date (week and year). For example, „1900" means the tire was made in the 19th week of the year 2000.
TUBELESS Tubeless tire.

Choosing Tires By Season

Summer Tires
They perform great on dry or wet asphalt, but are not recommended for snow or ice. They are designed to be used during the high summer temperatures and become too rigid when the thermometer drops below 7°C. Tire rigidity means low adherence and low car maneuverability.

Winter Tires
They give traction and high adherence on mud, snow and ice. They are made out of a low temperature resistant rubber that keeps all it's properties during winter conditions. The tread is designed so it offers adherence even when the asphalt is covered with ice. When driven on dry or wet roads, the maneuverability diminishes, they wear off faster and produce more noise.

All Seasons Tires
They combine the qualities of the summer and winter tires. In extreme conditions they are inferior to the specialized ones. They do not perform as good as summer tires on dry asphalt or as winter tires on snow. But their advantage is that you can use them all year round, on every kind of weather.

Other criteria for choosing tires:
- low resistance to rolling, which leads to fuel consumption efficiency
- low noise in all conditions
- retreading ability
- high speed or heavy load resistance
- driving comfort
- uniformity