Phil's Car Tips: Tires

In our first installment, we look at car tires, where the "rubber meets the road." Just thirty pounds of air in each tire holds up two tons of car.

JACKSONVILLE, Fla. -- What's the one thing that most people own, use it almost everyday and is the second most expensive purchase they ever make?

It's your car....

That's why every Monday on Good Morning Jacksonville Phil Amato will share some tips on how to maintain, repair and service your car so it will last longer and make your drives safer.

In our first installment, we look at car tires, where the "rubber meets the road." Just thirty pounds of air in each tire holds up two tons of car. In fact, only a five inch section of tire called the "contact patch" is on the road at any one time.

That's why you have to pay attention to your tires before they become a safety issue. There are four important aspects of a tire; tread type, tread depth, tire pressure and the age of the tire.

I talked with automotive expert Scott Lind at Planet Auto Service Center on Beach Boulevard and asked him what tire tread he recommends especially for rainy summer afternoons in Jacksonville.

Lind said a tire with wide spacing between the tread is going to allow the water to escape the contact patch instead of being trapped causing a hydroplane condition. That's when the "patch" fills with water, it no longer touches the road and can slip as if on ice. Here are a few examples.

Next is tread depth. Most of us know about the penny trick. If you see just the top of Lincoln's head your tires are worn and should be replaced. There's also another easy indicator. "Most of today's tire manufacturers have wear indicator welts built into the tread that can be easily seen. These lines will sometimes make noise when your driving as they are cross cut on the tread," said Lind. Here are some visual inspection tips.

We all know properly inflated tires mean better gas mileage but Lind says you don't want to guess how much air should go in your tire. "The tire pressure is one area most of us don't check enough. The correct pressure is important to support the vehicle weight properly and allow the tire to control the vehicles direction while turning. Most vehicles require varying pressures.

The pressure readings on the side of the tire usually indicate maximum tire pressure. However, you should consult your owner's manual or do a search on Google for the recommended pressure."

Finally, the age of the tire. "The National Highway Traffic Safety Administration (NHTSA) has no specific guideline. It defers to the vehicle and tires manufacturers for estimated tire aging. The accepted time limit by most experts is six years. But in a climate like Jacksonville's where heat, humidity and even the coastal salt air affect the rubber, that time can be significantly shorter. The best way to keep your family safe is to replace every 4 years or if there are visible signs of cracking on the side wall."

You can also easily tell when a tire was made. The Department of Transportation requires tires manufacturers to stamp the production date on the tires sidewall. The DOT production date is the last 2 numbers of the number series. Here's how to decode when a tire was made.

How do I choose the best tire for my vehicle?

  1. Determine what conditions you are likely to drive under and make a purchase to best suite the worst of those conditions. In Jacksonville we have a lot of rain during the summer months, so a good rain tire with deep wide grooved tread will work best.

  2. Determine if your vehicle requires a performance rated tire. Some vehicles such as a Corvette require tires that meet a speed rating as the vehicle can be driven at very high speed.

  3. Determine if you are likely to need a tire for use off road. Some vehicles can be used off road and selecting the tire to fit that need will important. Sand traction tires are usually wide and have a less aggressive tread, while mud traction tires usually have very aggressive tread that is self cleaning in off road conditions.

  4. Determine the tires size required to fit your vehicle. This information can be found in the owners manual. If you do not have the original manual, you can Google the question for a search result.

  5. Determine the "Load rating" to best fit your needs. Here is a great resource to help you with this technical question,

A final tip for making tires purchases is the price. Just because a tire is expensive does not mean it is the best tire for your needs. Some of the expense of the tire is called branding expense offset. This is really just a term used to explain the price of advertising that is built into the price of the tire.

Some manufacturers spend millions on advertising their product and that cost is contained in the price you pay for the tire. The best way to select a tire is based on the specifications of it's use and your needs, not price.

What about performance tires?

Many cars today require a performance tire due to the intended use of the vehicle. These tires are usually speed rated from "M", a tire rated only up to 81 MPH to "Z", a tire rated over 149 MPH. This information is contained in the tire coding located on the sidewall of the tire, here is a link to help you find the information . Here is a link for a complete chart to help you determine the tire speed rating that fits your vehicle needs. Performance tires also have different tread compounds.

This is the specific rubber make up the tire is manufactured from. Some compounds are "Hard" some are "Soft" depending upon the use of the tire. Tire designed to last a long time are usually made from "Hard" compounds to allow the rubber to resist wear from the friction created by the contact with the road.

These tires unfortunately do not make good traction because of the compounds strength causing a lack of flexibility. Tires manufactured using a "soft" compound wear very quickly from the road friction but they supply the best adhesion to the surface because the rubber becomes "Sticky" as the friction creates heat in the tires rubber.

This "Sticky" contact patch unfortunately has a short life span by the nature of the adhesion causing the rubber to shear away as a product of the adhesion. If you plan to drive the vehicle to it's performance peak on a regular basis, the "Sticky" tires will fit the bill, but that will come at an expense. Selecting a tire that can bride the gap between "Sticky" and "Hard" can sometimes be the best compromise.

Is there a difference between SUV or truck tires and car tires?

Yes, the tire used on an SUV or light truck has to support far more vehicle weight than you typical car tire. This has to do with the load rating of the tire, which your vehicle's manufacturer has a set requirement. This can be found in your owners manual or online by Googling you specific vehicle's "Tire loaded range requirements".

Most car tires are made to provide a good ride, handle cornering well and perform in all weather condition, but they are not usually designed to handle the excessive pressure of carrying heavy loads for long periods of time.

The tire pressure can be increased to handle more than normal, but there is a limit to the amount of weight that can be safely handled. Light truck and SUV tires are designed to be driven for extended periods at or near maximum load ratings. This allows for the vehicle to carry the maximum passenger numbers or heavy payloads to any distance needed. If you install "car" tires on an SUV or light truck, this could be a very dangerous decision and cause an accident.

How far can I drive on the temporary spare tire?

Early in the 1980's, vehicle manufacturers decided to save space and weight by removing the full size spare from the vehicle. The replacement spare was made thinner, lighter and in most cases designed for only temporary use. This is where the term "Temp tire" comes from. These "Temp tires" are not designed to handle highway speeds and are clearly marked as to the speed the tire is limited too for safely driving the vehicle.

The "Compound" used in these tires is designed to be light weight to help fuel mileage, this causes the "Temp tire" to wear out very quickly, usually only allowing for less than 500 miles of total driving. These "Temp tires are also not "All weather" tires and do not perform well in the rain. In fact, they can cause drive train damage if use on a drive axle position for extended periods as many of them have a slightly different diameter than the original tire.

The best use of the "Temp tire" spare is stamped on the side wall of the tire, "For temporary use only". When you car has a flat, install the "Temp tire" and drive to a tire replacement facility as soon as possible to limit both the potential for vehicle damage and your exposure to unsafe driving conditions.

Should I buy used tires?

In Jacksonville and other cities, the sale of used tires is very widespread. The use of a used tire in and of itself can be a money saving way to replace a warn tire. The problem is in that tires safety when installed on your vehicle. There are currently no safety regulation being enforced on the sellers of used tires.

This means there is no oversight and no rules governing the sale of used tires that would protect you from possible failure of the used tire. If a tire fails, it can have severe consequences and even be deadly for you and others around you if your vehicle goes out of control at highway speeds. As we noted in the "Tire tips" segment, there is a date stamped on the sidewall of the tire and the tire becomes dangerous after four years.

The problem is not limited to the age on a used tire. The used tire usually sits for a period while waiting to be sold. These Tires are exposed to sun, heat and other weather conditions that break down the tires rubber faster than under normal conditions. Tire that are not mounted on wheels can actually dry out from the lack of use. When a tire rolls on against the road it creates a friction that causes heat build up in the tire.

This friction caused heat is actually beneficial to the tires rubber as it causes a reaction in the rubber that keeps it's rubber molecules flexible. New tires have a coating from the factory that keeps the rubber compound "Lubricated" while awaiting sale. Even new tires have a shelf life with this coating, so without the coating they have a very short life.

Once a tire has been used for a few thousand miles, this coating dries and is absorbed into the tire. If you buy used tires that have been exposed to the elements while waiting sale, they will break down from the inside out.

You will not be able to visually inspect the tire and tell if the tire is still "Good" to use safely. If you should buy a used tire, you must check the date manufactured and make sure the tire is less than four years old and inspect the inside and out side of the tire for any visual signs of cracking. It is suggested a used tire be considered a temporary replacement.

My tires make noise when I drive, is the tire bad?

The tires on your car can be a great indicator of other mechanical issues your vehicle may have. If your tires are making noise, it is a sign the tread is warn unevenly. Car tire manufacturers actually test their tires to ensure they don't make noise when rolling against the road.

Off-road tires usually make noise because they are designed to be uneven to create a varying contact with the terrain allowing the tire to have maximum traction. This means if your passenger vehicle that is not intended for off road use is making noise from the tires, some mechanical condition exist causing the tire to be warn unevenly.

Wheel alignment, warn steering parts and warn shocks are just a few of the areas that can effect your tires warn patterns. When installing new tires, you should request these areas be inspected and make repairs accordingly or you will waste money on new tires.

Road conditions and driving habits can also affect the tires wear, so routine tire maintenance such as rotation, checking air pressures and cleaning can help your tires resist uneven premature wear.

Remember, once you hear the noise it's too late to save the tire from uneven wear, so preventative maintenance can save you money.


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