No one wants to replace their motorcycle tires sooner than they have to, and that’s why it’s essential to understand tire wear. Recognizing how your tire is wearing and what is causing it can help you get the most out of each tire.

Understanding Motorcycle Tire Wear: A Pile of Worn Motorcycle Racing Tires

Frequently Asked Questions about Motorcycle Tire Wear

In this article, we’ll take a look at a few of the questions that frequently arise about tire wear. If you’d like, you can read through the entire post as a single article, or you can just read the questions that interest you the most. Below is a list of questions answered, allowing you to jump directly to whichever question you want.

Motorcycle Tire Wear Questions and Answers

How do I know when it’s time to replace my tires?

The most important item to consider whether to replace your existing tires is if they are worn out or not. Worn tires lose their ability to perform at peak levels. Unless you race, this does not require replacements as long as you are careful. However, eventually they become dangerous when they are worn to a certain point. Most tires will include a tire wear indicator or wear bar of some sort. You can use this to help you gauge when it’s appropriate to switch out your tires.

What is a tire wear indicator and where can I find it?

The tire wear indicator, sometimes referred to as the TWI, is a small piece of raised rubber inside of a tread groove. Wear indicators are available on nearly every tire meant for consumer use, including motorcycle tires. Sometimes a triangle or the letters TWI will be located on the sidewall. These are used to help you find where the wear indicator is located on the tire’s tread.

Once the tire is worn down to the point of being on the same level as the wear indicator, it should be replaced. This ensures that you are able to use the tire as long as possible before reaching dangerous levels (when the tread is practically nonexistent).

Understanding Motorcycle Tire Wear: Tire Wear Indicator on a Motorcycle Tire

How does overinflation/underinflation affect tire wear?

Your tire’s pressure affects the contact patch of the tire – that is, the amount of rubber that is actually touching the road during normal operation. The diagram below illustrates this in a simplified manner.

Understanding Motorcycle Tire Wear: Contact Patch for Varying Levels of Tire Inflation

Tires are designed to offer their maximum performance and longevity when they are inflated at the proper levels. If they are overinflated or underinflated, they will not wear as intended. Improper inflation can even cause tire damage. For example, underinflation can create excess heat which can quickly damage the belts in radial tires.

A lot of tire wear depends on the proper inflation of the tire. How do you know what the right tire pressure is? Go with the motorcycle manufacturer’s recommendations, and consider how much extra weight you might be carrying with you (such as luggage or a passenger). The maximum psi listing on the tire sidewall is just that – the maximum, not necessarily the ideal. Going by this number will sometimes lead to overinflation.

You can read more about tire pressure by checking out this post.

Does it matter how old my tires are if they aren’t showing much wear?

Yes, it does matter. While actually riding the motorcycle is the most obvious cause for wear, tires are affected by other things, namely UV radiation and ozone. Exposure to these will prematurely age your tires. Even oxygen can contribute to tire deterioration.

Since you can’t really avoid these types of things whether you’re riding or not, knowing the tire’s age is important. Most experts agree that tires maintain their integrity for six years. After that, it’s generally a smart idea to get new tires, even if the tread appears good.

This countdown begins at the tire’s manufacture date, not the purchase date. So how do you know when the tire was manufactured? On the sidewall, every tire has a DOT code which includes various tidbits of information, one of which is the manufacture date. The date includes four digits and is often set apart from the other information in some way (such as being positioned on a raised block or surrounded by a border). The first two digits are the week of the year, and the last two digits are the year. So a tire with a date of 0614 is a tire manufactured in the sixth week of 2014 – in other words, February 2014.

What else contributes to tire wear besides riding and age?

Exposure to sunlight and extreme heat can both lead to the deterioration of a tire. Cracking in the rubbing is often a sign of sun rot and can indicate that the tire’s integrity has been compromised. Be wary of riding on a tire that you believe has suffered wear from the elements.

Never underestimate wear from weather or age. It’s more of an issue for some riders than many other forms of wear.

What are the little hairs on the tires? Do they have anything to do with wear?

Those are commonly called sprues or vents, and they’re simply a byproduct of the manufacturing process. During its construction, an unfinished tire is placed into a mold, and hot water or steam is injected the mold, expanding the tire into it. This ultimately gives the tire its final shape and tread pattern. However, as the rubber expands, air that was already in the mold must be able to escape; otherwise it will scar the tire. Tiny vent holes are placed throughout the mold to allow the air to leave the mold. A little bit of rubber also begins to exit through the vent holes as well – hence the term vents. (The term sprues refers to excess material protruding from a product that has been injection molded. While tires are not manufactured this way, this term is sometimes used to describe the hairs since they look similar to sprues created from an injection molding process.)

Tire sprues or vents wear off if they come in contact with a surface during regular use. The ultraviolet rays of the sun can also make them brittle over time, causing them to fall off. They are not true wear indicators since they come off so easily, and their presence or absence doesn’t necessarily mean anything.

Understanding Motorcycle Tire Wear: The Sprues or Vents Plainly Visible on a Street Bike Tire

What is a heat cycle?

A heat cycle refers to using your tires to the point where they heat up to their optimal performance temperature and then letting them cool back down. For most riders, heat cycles aren’t something to be concerned about. Instead, heat cycles come into consideration more with racing tires at the track, where speed is the main consideration and the tires get quite warm (and grippy). Many racers only use a set of tires through a few heat cycles, but if you only ride on the street and don’t use racing tires, you shouldn’t have to worry about how many heat cycles your tires have gone through. For street tires, the tread is a more important indicator.

My tire has been punctured. Can I repair it?

Motorcycle tires should not be used if they have been punctured or compromised in a similar manner. Their construction and design simply doesn’t support repairs. If you absolutely must ride on a repaired tire, it should only be in an emergency situation, and you should replace the tire before regular riding of any sort.

What is a motorcycle tire tear?

Normally, we would think of a tear as a fissure or opening, but a tire tear is something different altogether. Think of a tire tear as just a contraction of terrible wear, for that’s all it is. A tear is simply increased wear along a specific portion of your tire, usually indicated by numerous small pieces of rubber. While wear is normal, tire tear is not. It is usually an indication that something is wrong (such as improper inflation). However, it does not necessarily mean that you must immediately replace your tires. Have a tire professional inspect any questionable tire wear.

Understanding Motorcycle Tire Wear: Tire Tear on a Street Bike Tire
Photo credit: Björn (bambule) at Flickr

What does it mean if my tire has an irregular tear?

An irregular tear could include any of the following:

  • A tear with an uneven border
  • A tear which doesn’t cover the entire circumference of the tire

This may be an indication of a problem with your suspension.

What are cold tears and hot tears?

Cold and hot tears are types of damage that tires can get if they are either too cold or too hot. While some causes for these can include bike setup and driving style, improper inflation levels can also come into play.

When a tire is overinflated, its contact patch is significantly reduced. It heats up just fine, but it is small enough that it can’t create enough heat for the rest of the tire quickly enough. As a result, when you lean the bike in a turn, it causes a cold tear, which can be very deep damage.

Similarly, when a tire is underinflated, the contact patch is too large, so the tire actually overheats and creates a melting environment. The result is a hot tear on the side of your tire. This isn’t as deep as a cold tear, but it is a tear nonetheless.

My front tire often wears more on the left side than the right. Is this an indication of a problem with my bike?

Not necessarily. It’s actually a common phenomenon for the left side of the tire to wear a little bit more than the right side.

There have been several reasons put forth as to why this occurs. Here are a few of the more common ones:

  • It depends on personal riding habits, motorcycle balance and the roads frequently traveled.
  • The existence of road crowns, allowing rainwater to drain from the center of the road to the sides, causing wear on the left side of the tires since you ride on the right side of the road.
  • At intersections, left-hand turns are literally longer than right hand turns because of the necessity of positioning yourself in the rightmost lane of the road you’re entering, as demonstrated in the simple diagram below. This means that you literally ride a greater distance on the left side than the ride side of your tires.

Understanding Motorcycle Tire Wear: Left-hand Turns Compared to Right-hand Turns

The latter two suggestions in particular have gained a number of adherents because motorcyclists in countries which require driving on the left side of the road typically wear out the right side of their tires instead of the left side.

While it isn’t necessarily an indication of a problem, you might want to have your tire checked by a professional to see what their recommendation is if you find yourself wearing the left side faster than the right. It’s always better to have an expert provide their opinion before dismissing an issue.

How can I find out more about tire wear?

Dave Moss has become a recognized authority regarding tire wear. If you really want to learn more and have the time, he has an excellent video about it.

Conclusion

What frequently asked questions have you heard about tire wear, and what are your answers? Leave a note in the comments to share your own wisdom.

Technician Disclaimer