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.
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.
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