Sidewall Markings

The majority of riders know which tyre sizes are on their bike, but do they really know what a number such as 180/55 ZR17 M/C (73W) on a motorcycle tyre sidewall actually means?

Metzeler Roadtec01 180/55ZR-17

Metzeler = brand
Roadtec01 = model
180 = width (millimeters)
55 = aspect ratio (cross-section height is 55% of the width)
Z = speed rating (149mph or more)
R = radial construction
17 = diameter (inches)
73W = load and speedindex

WW = white wall tire
TT = tube-type tire (requires inner air tube)
TL = tubeless tire

 

Speed rating

You will find your speed rating on the side of your tyre. It is always represented by a letter. Typical complete mc tyre description: 120/70ZR17 (58W). Speed rating ZR – First letter is the speed rating and the second letter, if it is there, is an “R” (radial tire) or a “B” (bias tire). Lack of a second letter means it is a bias or non-belted tire. Last letter – “W” generally means higher speed rated than a standard Z rated tire.

SymbolMax SpeedSymbolMax SpeedSymbolMax Speed
J62 mph/100 kmhK68 mph/110 kmhL75 mph/120 kmh
M81 mph/130 kmhN87 mph/140 kmhP93 mph/150 kmh
Q99 mph/160 kmhR106 mph/170 kmhS112 mph/180 kmh
T118 mph/190 kmhU124 mph/200 kmhH130 mph/210 kmh
V149 mph/240 kmhW168 mph/270 kmhY186 mph/300 kmh

Motorcycle tyres’s speed ratings are established with new production tyres. MC tyres that have been repaired (patched), abused (used at a track day), or are worn down somewhat no longer qualify for their original speed rating.

Actual tyre speed and performance capability also depends on factors such as inflation pressure, load, tyre condition, wear and driving conditions.

Speed ratings are based on laboratory tests where the tire is pressed against a large diameter metal drum to reflect its appropriate load, and run at ever increasing speeds (in 6.2 mph steps in 10 minute increments) until the tire’s required speed has been met.

It is very important that you check your speed rating before buying your mc tyres. You should always follow the motorcycle manufacturer’s recommendations, if any, concerning the use of speed rated tyres and ensure that you are familiar with the speed markings of the tyres that you buy.

 

Load rating / index

The load index is a numerical code that corresponds to the maximum weight a tyre can support. A tyre’s load multiplied by 2 must cover the gross single axle load of your vehicle. To determine your load index, locate the number on the sidewall of one of your tyres and compare it with the load index table.

Example: 160/60R-17 (69W). So this tires load rating would be 325 kg or 720 lbs.

LIKGLB
2182.5182
2285187
2387.5193
2490198
2592.5204
2695209
2797.5215
28100220
29103227
30106234
31109240
32112247
33115254
34118260
35121267
36125276
37128282
38132291
39136300
40140309
41145320
42150331
43155342
44160353
45165364
46170375
47175386
48180397
49185408
50190419
LIKGLB
51195430
52200441
53206454
54212467
55218481
56224494
57230507
58236520
59243536
60250551
61257567
62265584
63272600
64280617
65290639
66300661
67307677
68315694
69325716
70335736
71345761
72355783
73365805
74375827
75387853
76400882
77412908
78425937
79437

Tyres are offered in different load carrying capacities. It is extremely important not to exceed the max. load rating. You must take the weight of the motorcycle, the weight of any optional equipment, as well as the weight of a passenger into consideration before determining what the “Load Capacity” of your tyres should be. A tyre’s load carrying ability can be reduced by underinflation. You can overload a tyre even if it is the size specified by the manufacturer.

 

Dot numbers – “Department of Transportation”

The age of motorcycle tyres may be determined with the help of the DOT number. This number may be found on the side of the motorcycle tyre. These numbers let you decode the date of manufacture of the tire. The first two numbers indicate the week; the last two the year. For example, 3811 indicates the tire was produced in the 38 week of 2011.

Tyres are generally developed and produced so that the production features remain effective for their entire life span. Still, each tyre is subject to an ageing process, which also occurs during storage. Due to the different profiles, rubber compounds and constructions the ageing process is different for each tyre.

We only sell brand new tires (under two years of production).