| Let me take a swig off my bottle of Moxie soda and | | | | Hey! Let's list an example and use the 195/75R14 tire |
| get this article started, you young whippersnappers. | | | | as our base, okay? |
| There was once a day when we had only three | | | | 195/75R14 |
| television networks, plus PBS -- which barely anyone | | | | 205/70R14 |
| watched. We had a choice of one or two radio | | | | 215/65R14 |
| stations on static-ridden AM radio for our choice of | | | | 225/60R14 |
| music. If those stations played the same song at the | | | | 235/55R14 |
| same time? Tough luck. | | | | 245/50R14 |
| It was also easier to install a wider set of tires on your | | | | These days, most people would be crazy to go any |
| car if you wanted to give it a squatty appearance. | | | | lower than a 60-series tire on a 14-inch rim. Why? |
| We'd go to the local tire dealer, point out our brand of | | | | Because, you can jump to a wider wheel instead! By |
| choice and they'd mount them, balance them and off | | | | purchasing a wider diameter wheel, you'll actually |
| you'd go; in a quest for your next speeding ticket! But | | | | reduce the rubber sidewall and replace it with nice, rigid |
| as cable TV arrived, along with new radio stations up | | | | steel or alloy or whatever your wheels happen to be |
| and down that new-fangled FM stereo dial, we also | | | | forged out of. This drastically increases handling. |
| saw more choices with our tires and wheels. Suddenly, | | | | Rubber will flex under stress, steels and alloy wheels |
| it became a more complicated world. McDonald's | | | | will not. |
| began selling more than just burgers, while Coke and | | | | Jumping from a 14-inch wheel to a 15-inch wheel is |
| Pepsi began selling more than just cola. | | | | called a "Plus 1" application. Jumping to a 16-inch wheel |
| To many of you, this is ancient history and you're | | | | would be a "Plus 2," and it doesn't take a genius to |
| already yawning, looking at your watches and hoping I'll | | | | figure out what you'd call a 17" wheel change. And up it |
| get to the point sometime during the next few | | | | goes, all the way to the 20-inch range! |
| sentences. So here we go.... | | | | When you trade off some sidewall height for wheel |
| Tire Width | | | | height, you can actually begin to squeeze a little more |
| Who doesn't want a nice set of road-grabbing sporty | | | | width into your wheel wells. Basically, I've found that |
| tires? The wider-look has been popular on cars since | | | | the tread width now changes to 20 percent of aspect |
| 1964, when Pontiac decided they needed more | | | | ratio. In other words, if you had a 205/70R14 tire and |
| rubber-on-pavement to handle the additional | | | | purchased new 15" wheels, the tires would have to be |
| horsepower from their cool, new GTO. By the time | | | | changed (of course) to a 205/65R14. But you're |
| 1970 rolled in, the rear tires on many muscle cars were | | | | looking to improve performance, so it's best to go to |
| wider than your mother-in-law's backside. | | | | the 60-series. This is where my "20%" rule applies...and |
| Let's look at how we widen a tire first. There are three | | | | it works. |
| numbers on a tire. The first is the width, in millimeters, | | | | The closest ride height and correct speedometer |
| the second number is the "aspect ratio" and the third is | | | | combo for the "205/70R14, Plus 1" would be a 225 |
| the wheel diameter. Pretty simple....uhhh...wait...aspect | | | | 60R15. For a "Plus 2," you'd jump to a 245/50R15, and |
| what? | | | | for a "Plus-3," you'd be at 265/40R17. |
| The aspect ratio is the percentage of the tread width | | | | I have seen many guys stuff an extra 10mm in there. |
| in sidewall height. Simple, huh? | | | | A 235/60R15 would actually fit with a little luck and |
| Let's say we have a 195/75R14 tire. (It's just sitting | | | | strong suspension. (This small paragraph was meant |
| there in your living room, hoping you don't watch | | | | to confuse you. I'm sorry, but it's true.) |
| American Idol.) The "195" is the tread width. The "75" is | | | | Naturally, you're going to want to check with your local |
| the percentage of that "195" number. This means your | | | | tire dealer to verify your conversion needs, but these |
| tire's sidewall height is...taa-daa...146mm! Don't worry | | | | simple formulas have always worked for me - a |
| about the "R14" part, we know that the 14 is the wheel | | | | former B.F. Goodrich Certified T.A. Specialist. But for |
| diameter in inches, but the "R" is a speed rating, which | | | | your own research into possible wheel/tire |
| I'll cover at a later date. | | | | combinations and pricing at your own convenience - |
| For a sporty look, most people will naturally choose | | | | without a tire salesman breathing down your neck -- |
| slightly-wider tire. So, you'd increase the width by 10 | | | | my numbers will guide you. |
| millimeters to a "205". Cool, right? | | | | One final thought. Have you seen the really, really big |
| Wrong. | | | | wheels on cars and SUVs? These tire/wheel combos |
| By changing to a 205/75R14 tire you've just added | | | | are not just an embarrassing attempt at style, but they |
| 8mm in sidewall height. You have to lower that pesky | | | | actually damage suspension and are a detriment to |
| aspect ratio or not only will your car be riding higher, | | | | the vehicle's handling. There is not enough rubber to |
| but you'll also by throwing-off your speedometer by | | | | absorb road shock and this wears at all the front end |
| about 2MPH less. And if you'd jumped to say a 215 | | | | suspension parts. This inability to "spring" can create a |
| 75R14 tire, you'd have raised your car's ride height by | | | | dangerous bounce that can cause temporary loss of |
| almost an inch! | | | | control. |
| The simple rule of thumb to use when increasing tire | | | | The rule of thumb for big wheels is this: For every |
| width is: for every 10mm in width, you must drop the | | | | wheel diameter over 18-inches, remove 25 points from |
| aspect ration by 5 percent. That's pretty simple stuff - | | | | the driver's I.Q.. |
| even for Idol fans. | | | | Drive safely! |