Low Prices Without Sacrificing Quality!
In a perfect world, there is an ideal tire which has incredible traction in rain, snow and off road, corners and brakes like a racing slick, has a soft ride, is perfectly quiet, lasts over 100,000 miles, and cost five bucks. However, for those of us living in this world, everything is (tires at the very least are) a compromise between different attributes. The best we can do is select the tire which has the best combination of attributes for our vehicle and our needs. In this article, we'll seek to help our customers make an informed choice. We will discuss:
The Difference Between Circumferentially Arranged and Radially Arranged Tread Blocks
and we'll also cover:
Circumferential tread designs have tread blocks arranged in a straight line around the circumference of the tire, and disperse water by cutting through it. On the other hand, radially arranged have tread blocks that go across the tire, or more commonly from the middle to the outside of the tread, and grab the road or surface as the tread goes by. Circumferential type treads will have low rolling resistance, resistance to cupping, a quiet smooth ride. They will be good in the rain, but can be awful in dirt or snow. Highway tread and many all season tires are made this way. Tires with radially arranged blocks are still good in the rain, but will be better in dirt and snow. For this reason almost all all terrain, and all mud tires have radially arranged blocks. The difference between an all season, an all terrain, and a mud tire is mostly the amount of "tread void", or space between the tread blocks.
The main point is this: Even though most circumferential groove tires are ususally M+S rated, they may very well be completely worthless in the snow, so if you're actually going to need traction in snow or dirt, you should buy tires with more bite.
Characteristics of tires with circumferential tread blocks:
Circumferential Groove Tire
Qualification: Even though these tires resist uneven up and down wear along the length of the tire, or cupping, they are not immune to it. If you get this type of wear anyway, you may have a vehicle condition such as improper alignment, or an inherent design issue, like in some European cars or four wheel drives. On the other hand, if you know you have a vehicle that is prone to this, putting this style tread will minimize the cupping. Rotating your tires regularly will also help minimize this type of wear.
Characteristics of tires with radial tread blocks:
Radial Tread Block Tire
Details: Many all season tires, snow tires, and most all terrain tires have this tread style and are still inherently quiet. However, it is important to keep them rotated to keep cupping to a minimum so that they will stay quiet. Mud tires and the few tires "in between" all terrain and mud will usually make noise and it is critically important to keep them rotated. Full mud tires will pretty much always cup, but rotations will keep it under contol, and will help improve treadlife on all types of tires.
Overview: Since tires for all vehicles come in highway/all season and snow tires, and truck/suv tires have all terrain and mud tires options as well, for the purposes of this discussion, we'll lump the vehicle types together. The principles apply no matter what vehicle type you have.
If you were going to make a graph, (we would if our graphics skills were better!) it would look something like this: On the top of the graph you would have the circumferential grooved, tight tread tires, and as you went down the graph, the tread would be arranged more radially and the tread voids would get larger, with snow tires being somewhere in the middle. If these tires all had the same tread rubber (which of course they don't), the tires on the top would be quieter and longer wearing while they would get better off road traction and less wear as they went down the scale. However, the exception to this is the snow tire. A medium tread void with a lot of siping is best in snow, but we'll explain in more detail as we go. We will discuss the tires in decending order like in our (ficticious) graph. All of the tread designs shown are representative examples only, there are many variations.
Highway/All Season Tire Characteristics:
All Season Car Tire
All Terrain Truck/SUV Tire
Details: As stated above these tires will be good in the rain, quiet, and relatively long wearing. However, they make tires with this type of tread from 20,000 up to 100,000. So a moderate tread will wear better than a more aggressive tread with the same rubber compound, but more depends on the individual tire. As far as the cupping (uneven up and down wear along the face of the tire) goes, a more moderate tread will cup less than a more aggressive tread - rotations are still important to keep it to a minimum. In truck and SUV tires, the higher mileage rated tires, (60-70,000 miles) are all of this type.
Radial Tread Block All Season Tire Characteristics
This type can be a little more susceptible to uneven wear, but are inherently quiet, so if you keep them rotated, unveven wear and noise will be minimal.
Snow Tire Characteristics:
Snow tires are differentiated from M+S tires in that they are not merely allowed for snow, but they are designed specifically and optimized for snow. Therefore, they are often called "seasonal" snow tires, even though you can use them all year round. Since they are made for all vehicles types, including low profile tires for sports cars, we've listed them before all terrain tires, which are only made in truck and SUV sizes. A good all terrain tire will be much better in snow than an all season. However, a "seasonal" snow tire is head and shoulders better than either one in snow, and even rain. It's hard to emphasize this difference enough, there is simply a world of difference between snow tires and the others in the snow that you really can't understand unless you've driven on them.
The secrets to their traction are the tread design and the rubber compound. If you look at the picture, you will see larger tread "voids" (the space between the blocks) than the all season tires and quite a lot of siping (the cuts on the individual blocks) You will also see chamfering and fluting along the edges of the individual tread blocks. All of these individual biting edges, and the special (softer) rubber compound give amazing traction in snow. However, the softer rubber compound will make the tire wear faster, usually only around 35,000 miles.
A note about siping: Some shops offer added siping, and our favorite consumer magazine tested this. Their finding could be summed up as follows: In their test, added siping improved traction in ice and snow, and worsened traction on wet and dry surfaces. Since snow tires have a lot of siping to begin with, we would say that this is of limited value. However, we will give a more thorough explanation of this later on in this article.
All Terrain Tire Characteristics:
All Terrain Car Tire
Details: The majority of current all terrain tires are quiet on the road. However, you will want to keep them rotated. Since all terrains have a little more aggressive tread, they are more prone to cupping, so the rotations keep this under control. A "normal" all terrain tire is rated around 40,000 miles. However, most of the better options are rated for at least 50,000 miles, so they can still wear pretty well.
"In Between" All Terrain and Mud Tires:
In Between All Terrain and Mud
Details: There are actually only a few tires in this category, but they represent a very good compromise between all terrain and mud tires. Pretty much everyone we've sold these to has really liked them.
Mud Tire Characteristics:
Qualifications: A lot of people think that the more aggressive the tire, the better it will be in snow. However, full mud tires have very poor traction in snow until it gets deep, approximately 18" or more. Then they'll be amazing, but for smaller amounts of snow, a good all terrain or snow tire will be much better. However, when it comes to Mud, you need the very large tread voids that the mud tires have to release the mud from the tire, and then you have to have muds, or at least the "in betweens". These are also the tire of choice for serious off road use.
High Performance Tires
By high performance, we mean tires that are rated for higher speeds, are mostly low profile, and have better stopping and cornering performance. Many of today's cars, even family cars like Camrys, have high performance tires, and there a number different types. We will try to explain the differences, so you can choose the tires that are right for you.
Fundamental to any discussion of high performance tire is understanding speed ratings.
Common Speed Ratings are:
S = 112 mph, T = 118 mph, H = 130 mph, V = 149 mph, Z includes: W = 169 mph and Y= 186 mph.
You many wonder why some of these are odd numbers, and it's because they were originally in kilometers per hour. For instance 118 mph = 200 kph, 149 mph = 240 kph, 169 = 280 kph, and 186 = 300 kph.
The general rule for speed ratings is as follows:
The higher the speed rating, the better the tire will corner and stop, the more it will cost, and the faster it will wear out. There are many variables to this since there are more and more H and V rated tires with 60 to 70,000 mile ratings, and the fact that one Z rated tire may perform substantially better than another. However, in both of these cases the rule applies: A T rated 80,000 mile tire will usually cost less than an H or V rated tire rated for 60,000 miles, and a more expensive Z rated tire will usually corner better and wear faster than an inexpensive one.
Some retailers will refuse to put a tire on with a lower speed rating than the one recommended by the manufacturer. To date, we have yet to find any law requiring this, nor have we found any manufacturer or insurance company that requires this. Therefore we leave this decision to the customer. Here are some of the things you'll need to consider to make an informed decision:
Advantages and Disadvantages of Higher Speed Rating Tires:
To sum up: If you drive your vehicle hard, or just want the added safety of shorter stopping distance and better cornering, a higher speed rating will be a better choice for you. If on the other hand, you drive calmly and would prefer higher tread life, then a lower performance, higher mileage tire would be a better choice. Or if you want the best of both worlds, there are choices for that also. However, all of this is subject to availability in your particular size.
Sipes are the small cuts in the tread blocks found in most tires. If you look at the "snow tire" picture above, you can clearly see this. The fact that they are found in most tires, and in huge numbers in snow tires means that they are a good thing. However, some of our respected competittors promote adding siping to the tires. If some is good, more is better, right? Well, maybe. Our take on the subject is that properly engineered siping specific to the tire is definitely good, but adding more siping depends on the situaton. Here is our reasoning:
Our favorite consumer magazine actually did a test on adding siping to the tires. Their findings can be summed up as followed: Tires with added siping performed better on snow and ice than the original tires, however, their traction was not as good as the non-siped tires on wet or dry! We would take from this that if you are in a lot of snow and ice, then adding siping to the tires could be advantageous. However, if you have seasonal snow tires, they have so much siping to begin with, it probably wouldn't make a difference.
Also, there are some tires that come with little or no siping. Two good examples would be Mud Tires and ultra high performance tires. In both of these cases, adding siping to the tires will have the effect of destabilizing the tread blocks. In the case of the mud tire, the tread blocks will move around more and the tire will feel relatively "squishy" compared to a tire without added siping. In the case of a high performance tire, the siping will decrease dry traction. In our opinion these types of tires should never be siped. There is a third type of tire (that we can think of) that has little or no siping, and though there are not a lot of them, some of the least expensive economy tires don't have much siping. In that case, we don't believe that it makes good sense either. For the price of the siping, you could simply upgrade to a better tire. The better tire will usually have more siping and a longer wear rating!
In the past, we had also heard claims that since siping reduces heat build up in the tire, then adding siping would increase treadlife. However, we couldn't find anyone currently claiming this, and in the wikipedia article on siping (if you trust them), it stated that added siping decreases tread life. Again, even if adding siping did increase treadlife, for the cost of adding siping, you could step up to the next better wearing tire.
Considering Tire Aging When Selecting Tires
Although we already have an entire article on tire aging, it bears note here because of it's impact on the tire selection process. Since rubber degades over time, and tires become unsafe to use when they get too old, high mileage tires are not usually a good choice for vehicle that don't see many miles. Sure, the better tires will drive better, but since you should replace your tires every six years (industry standard), it doesn't make sense to put 80,000 mile tires on vehicles that are only used 5,000 miles or less per year. Whether you put 40,000 mile tires or 100,000 miles tires on a vehicle, the same time limits for safe usability apply. Either tire should be replaced after six years.
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