Sunday, 01 August, 2021

Motorcycle Tire Guide 101 – All About Tires


Here we’ll be having a crash course (figuratively speaking, keep the shiny side up people!) on Motorcycle Tires! This Motorcycle Tire Guide is a complete, comprehensive guide to the world of motorcycle tires.

At Lucky Cycles, we see all kinds of customers’ bikes. The rookies on Ninja 300’s, R3’s, and Rebels. The long distance tourers on their big baggers. Even race riders on liter bikes! And those are just the street riders! As you may have guessed, all of these motorcycle riders have different needs & wants when it comes to selecting a tire.

Motorcycle Tire Guide: Tire Construction

  • Bead – This is the part of the tire that secures it to the wheel. Usually made of steel wire and tacky rubber so it fits right against the wheel and prevents rotational slipping of the tire.
  • Carcass – In simplest terms, this is the ‘body’ of the tire. Tire carcasses for motorcycles generally come in 2 types: Radial, or Bias Ply. Radial tires have reinforcing belts (which are almost always steel) running from bead to bead across the tread of the tire. Bias-ply tires have belts which are typically cords made of fiber, such as polyester, aramid, or fiberglass, that run from bead to bead at an angle of 30 to 40 degrees or so. (That angle is the ‘bias’!)
  • Sidewall – The sidewall makes up the side of the carcass between the tread and bead. A small part of the tire, it is vitally important. It gives the tire much of its handling and load transfer characteristics. This is the part of the tire we’re talking about when we reference height, profile, or aspect ratio. Typically, a shorter sidewall yields a stiffer sidewall, which tends to flex less. To a rider, this means better handling and turning, worse bump absorption, and more difficult mounting. This section greatly contributes to the tire’s role in the suspension. You heard that correctly, the tire is a suspension component!
  • Tread – This is the part where the rubber meets the road. Literally! It’s also the first thing that most people think about when looking at tires. In general, smooth tread patterns work better on dry pavement (the reason most race tires are slick) and big, chunky tread blocks work best off road. Everything else falls somewhere in between. Some street tires have tread patterns designed to do better on wet ground, while off-road tires come in a wide variety for different surfaces, from hard-packed dirt to loose sand and gravel.
  • Rubber Compound – The rubber materials of motorcycle tires are generally divided into soft, medium and hard compounds. Soft compounds have better grip, but wear faster. As you may have already guessed, hard compounds are the opposite. They give up some grip in favor of long wear life. Medium compound tires fall somewhere in between. Some tires, like the Dunlop Q4 Sportmax, and Pirelli Diablo Rosso III are multi-compound tires. They use a hard compound in the middle of the tread (where most street wear occurs), and a softer compound on the sides for better cornering performance.

Motorcycle Tire Guide: Cracking the Code

How do you figure out what size a tire is, how old it is, it’s max pressure rating, and other pertinent information? It’s easy! By law, this information is all cast or embossed into the sidewall of every tire.

There are two ways to give tire information: alphanumeric and metric. Alphanumeric is the ‘old’ system from the decades before radial tires existed. Back then, there weren’t many different wheel/tire sizes, so a simple system worked well enough. As increasingly complex tire technology became available, it was evident a new system needed to be cooked up to provide that information to consumers and sellers, so the metric system was developed. 

In the example above, the tire sizes are given in metric format. The tread section is 195mm wide, the sidewall height is 55 percent of the section width, and the tire fits a 16″ wheel. Other information shown are speed ratings and load ranges. Load ranges give the maximum weight a tire can carry, and speed ratings list the maximum speed at which the maximum load can be carried.

Load
Index
Load
(lbs.)
Load
Index
Load
(lbs.)
Load
Index
Load
(lbs.)
1 99 31 240 61 567
2 102 32 247 62 584
3 105 33 254 63 600
4 107 34 260 64 617
5 110 35 267 65 639
6 114 36 276 66 639
7 117 37 282 67 667
5 120 38 291 68 694
9 123 39 300 69 719
10 128 40 309 70 739
11 132 41 320 71 761
12 136 42 331 72 783
13 139 43 342 73 805
14 143 44 353 74 827
15 148 45 364 75 852
16 152 46 375 76 882
17 157 47 386 77 908
18 161 48 397 78 937
19 165 49 408 79 963
20 171 50 419 50 992
21 176 51 430 81 1019
22 182 52 441 82 1047
23 187 53 454 83 1074
24 193 54 467 84 1102
25 204 55 481 85 1135
26 209 56 494 66 1168
27 215 57 507 87 1201
28 220 58 520 88 1235
29 227 59 536 89 1279
30 234 60 551 90 1323

The above chart shows the various possible load indexes. The chart below covers the speed ratings.

Now that you have a handle on the various sizes & speed ratings, we’ll tackle tire age.

How do I know how old a tire is?

Molded into the sidewall of every tire is a DOT code, typically ~12-16 digits. It starts with the letters DOT (as in Department of Transportation) and ends with a seemingly random string of numbers and letters. Much like the tire size, this string of numbers and letters means a lot.

If there is a three-digit number in the final block of numbers, the tire was produced prior to 2000 and definitely needs to meet the nearest dumpster ASAP. Even a 5 year old tire should at least be checked over closely by a professional if not replaced. Better safe than sorry!

How can I tell when my tires need to be replaced?

Let’s run down a quick list of scenarios that should lead to your motorcycle tires being replaced:

  • Sidewall puncture
  • Damage that can’t be repaired
  • Tire with a puncture larger than 0.25 inches
  • Tire more than 5 years old
  • Weather-checking (cracked around the circumference or between the tread blocks), often due to UV or fluorescent exposure
  • Tire that has been run awhile with low pressure (damage is typically seen as a circumferential ring that looks “rubbed in”)
  • A with cuts or slices
  • Tire with missing tread blocks
  • A that is worn (less than 3/32 of an inch of tread in any area)
  • Tire displaying treadwear indicators
  • A that has cross section significantly altered (flatter or more pointed due to uneven wear)
  • Tire that is feathered or cupped and is making noise or exhibiting a choppy ride; some front tire cupping is normal, but a worn tire may exhibit severe feathering.

Considering most bikes have a tire speed rating, and repaired tires lose their speed rating, many riders with any type of tire puncture really need a new tire. 

Have a question we didn’t cover here? Leave a comment below or send us a message on Facebook

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