We have a Metzler 180/55 ZR18. The “180” is the tire width in millimeters. The “55” would be the aspect ratio. The aspect ratio of this tire is the relationship of this tire’s cross-section height to the cross-section width. In this particular tire, with an aspect ratio of 55, for example, height is about 55% of the tire width. The next marking on the sidewall is the ZR. The Z tells you what speed the tire is rated at and the R simply means “radial.” Here is a speed chart showing that the Z on this particular tire means that the tire is rated at 150MPH+ and the last number we see here is 18 and that’s just the rim diameter in inches. Moving to the right, we then see the directional for this rear tire. Next we see the max load rating, that’s 627 pounds at 42PSI. Remember, measure your PSI when the tires are cold and the final piece of information on this tire is what it’s made out of. When do you need new motorcycle tires? Most motorcycle tires have wear indicators. Take a look. Take a look at the arrow on the sidewall of this tire in the center of the frame. This arrow points to wear indicators as shown right here in this tread groove. When the overall tire wear gets down to these bars, it’s time to replace your tire. If your tires don’t have wear indicators, always remove tires from service when they reach 1/32 of an inch tread depth. Dunlop recommends using a penny to test this.
If you insert a penny into the groove at the center of your tire, 1/32 of an inch is right at the top of Lincoln’s head. Another common question we get asked is: which tire is best if I’m going to be riding in the rain? My general answer to that question is, any tire with decent tread will be a decent tire to ride in the rain on. Most all tire manufacturers recommend running a matched set of tires. These tires from Avon, for example, are matched front and rear. The cornering characteristics should be about the same. They’re going to have similar stickiness characteristics as well as longevity characteristics. Here is a matched set of wide white wall front and rear tires. White walls come in an array of sizes from just about every manufacturer out there. One thing to be careful of when order white wall tires is whether you’re getting the narrow stripe or the wide white wall. Here’s an example of the wide white wall in the foreground and the narrow stripe in the background. So where do you find what size tire fits your motorcycle? There’s one of two ways you can do this. You can walk out to the bike, you can read the sidewall of the tire, and that will tell you what size tire you need. Or you can click on our tire finder, found in the upper left-hand corner of most of the search pages on our website. Load rating is another key component.
This tire here has a max load of 551 pounds this one here, 627 pounds and finally this one here, 910 pounds. Another key thing to look out for is whether the tire is a tube tire or a tubeless tire. If fitting a tubeless tire on a tube rim, make sure you insert a tube. Another common question we get is: how large of a tire can I go over stock? The trend over the last couple years is to put the biggest rear tire on your bike that you can possibly get on the bike. Check out the new industry leader measuring 420MM. Metzler has a really good chart showing the largest recommended tire you can put on your motorcycle. What is the most important thing that I need to do to my tires to make sure I’ve got a safe and reliable ride? The A number one thing I’m going to stress is tire pressure. While picking your bike up from the dealership after having a new set of tires installed, I recommend the following.
- Number one, check the directional arrow to ensure proper direction.
- Number two, double-check your tire pressure.