Cheap Tire

Cheap Tire Guide


The Anatomy of a Cheap Tire: Internal Construction

Published October 24th, 2008 in General Tire Information, Tire Construction | No Comments »

Let’s take another look at our tire information:

P255/50R16

This means we have a P-metric general passenger type tire with a 255mm section width.  Nothing fancy so far.  Continuing down the line, we see that the profile is 50% of the section width, which puts it at 127.5mm.  Note, the smaller the third term in the string the lower the profile of the sidewall will be.  Thus, if you’re looking for a low profile tire, or slicks as some people call them, you’ll be looking for a very low number to occupy that space.  Especially if they’re a very wide tire.

When looking at a tire for a truck, people generally want a higher third term for a taller tire, where width isn’t so much of a factor.  But due to manufacturing processes and engineering, you’re generally going to find a higher second term as the profile gets higher.

This brings us to the fourth term, which tells us what the internal construction of the tire is.  I get asked all the time if this separates a cheap tire from an expensive tire, and the answer is always no.  The internal construction of the tire has very little to do with price, since most tires in this day and age are R-type, or radials.

What this means is that the tire construction is a series of rubber plies that radiate out from the center of the tire where it fits around the rim.  In other words, imagine that there are 10 layers of rubber from the outside surface of the tread to the inside where the pressurized air is held.  If you were to cut the tire drop top to bottom to look, it would almost look like a horseshoe.

Other constructions that you might see are D for diagonal, or bias-ply, where the plies of rubber are laid at a 90 degree angle to each other, diagonal across the tire as it would travel on a vehicle.  B indicates belted, which is similar to bias-ply construction except it is reinforced with belts under the tread area.

More than 95% of all tires sold today are of radial construction, cheap tire or expensive tire.

Tire Section Width and Sidewall Aspect Ratio

Published October 24th, 2008 in General Tire Information, Tire Sizing | No Comments »

These two topics are fairly straight forward, so I’ll cover them in one article.

Come to think of it, why people have such a hard time explaining what the section width and aspect ratio are continues to elude me.  People in the tire business for years and years know what it is, can articulate what it is, but can’t translate it from tire lingo to “normal speak”.  I see customers leave my shop every day with bewildered looks on their faces because one of my tech just put them through the information wringer.  So I’ll attempt to break it down in basic term that everyone can understand.

Section width is the width of the tire.   There, simple right?  I’m sure most people reading this are asking “what width?” right now, and that’s where people usually get hung up.  So if we’re looking down at a tire that is stand up in a position where it would roll away if you pushed it, such that we’re staring down at the tread, the section width is basically the width of the tread in millimeters.  It goes a little further than that but measuring from the fattest part of the sidewall on one side to the fattest part on the other side, but that’s not so important.

So a LT275/50R16 91S is 275 millimeters wide from sidewall to sidewall if you were to puncture the cheap tire at its widest point with a ruler.

Now, sidewall aspect ratio is not an absolute measurement like section width is.  It is a percentage of the section width, and determines how “big” your tires are from the rim to the tread.  This is also referred to as the tire section height, aspect ratio, or profile.  For an example, our LT275/50R16 91S measures 137.5 millimeters from the tread to the rim, because 275mm x 50% = 137.5mm.

That means the higher the aspect ration the taller your tire will stand.  At the same time, the greater the tire section, the greater your tire will stand.  So both of those figures play into the actual size of your tire.  Remember that, it’s important.