Some folks buy a tire with a certain look and feel but don't realize that although their badass chopper can cruise down the highway at 110 MPH, their cool-as-hell vintage-tread tire can not. With that in mind, read this short yet informative presentation about understanding the sidewall markings on tires so you know what they are capable of, then wish your girlfriend's tramp stamp came with the same warning labels.
To make things easy, motorcycle tires have their own set of codes.
- Height/width aspect ratio
- Wheel diameter
- Load index and speed rating – Load index is the weight the tire is capable of handling when properly inflated. Most tire manufacturers show on the sidewall what that maximum load is so there is no guessing. This includes whatever weight your bike is adding at that wheel- yourself, beer, your passenger and all the crap she's hauling with her, etc. You will usually find it listed with the tire’s maximum air pressure.
Let's start with a breakdown of some of these codes. Here's one of our cool new rear tires, the Shinko 270:
Shinko gets down and dirty and in your face- just like back in the day. This is a great vintage detail lost on a lot of newer tires. Don't worry, these are truly modern tire rubber compounds, they just don't mark up their tires with lots of crap the lawyers told 'em to put on there. Shhhh.....*winking emoji-thing*
Speed ratings are pretty NASA, forcing some to pause to wonder what the hell the "H" stands for. Fun indeed for Google fans, but for chopper folks it's just nice to have "how fast can I go before I find out how comfy that ditch is" spelled out right here, right now. If you want to know about Sidewall Speed Symbols (Rating), Check this out:
Here's another good number to pay attention to - don't forget your bike and gear adds to the weight of your ass sitting on the back tire. Not so much to worry about since we spend more money on our rides than food, but keep this number in mind the next time you brag that your angle iron sissy bar can carry a half-barrel of Blatz.
Here's how sidewall markings look on our popular Avon Speedmaster "tyre" made in England. Although a bit different, tires from all over the world have to comply with DOT regs if they're going to be sold in the USA, so the info has to be there. Including a bunch of man-nipples which are sure to become conversation starters. ANYWAY...
Here's the load rating on the Avon. This is a front tire so the load rating is going to be significantly lower. No problem, there isn't a whole lot of weight on the front wheel (hopefully).
You can certainly find more in depth info on these numbers and letters out there on the web, but for the most part this info should serve you well when choosing a tire. Keep the rubber side down...