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