some more FAQ:
Q. Is there a big difference between Summer Tires and Winter Tires?
A. Yes, there are actually extreme differences between not only summer & winter tires but all-season tires as well. Winter tires will have bigger grooves for snow, some actually designed to grab the snow and throw it as traction. Winter tires also have softer compositions then all-season tires. Summer tires will have enough groove for rain and keep more rubber to the road for dryer conditions.
Q. How much air should I put in my tires?
A. Each tire manufacturer as well as each car manufacturer will have different suggested tire pressures for each vehicle. Different tire pressures will also affect vehicle ride & performance along with the tire wear. Feel free to stop in to Acme Tire and we will be happy to check your air pressures and measure your tire treads.
Q. Under inflation vs. Over inflation?
A. An under inflated tire reduces fuel economy, generates excessive heat, and increases tread wear in the shoulder area. Inflating your tires can improve your fuel economy and extend tire life, but over inflation can not only be dangerous but can cause the tires to wear in the center and decrease tread life. Generally, the maximum inflation pressure for most passenger cars will have tire pressures that range from 32-35 psi.
Q. How often should I check my tire pressure?
A. It is a good idea to check your tire pressures every few weeks and definitely before any long trips. Tires actually always lose air but at an incredibly slow rate unless there is corrosion around the wheel, leaky valve stems, or of course some type of projectile stuck in the tire. Check and adjust inflation only when tires are cool.
Q. What should I do if I notice a vibration while driving?
A. Any form of vibration no matter the cause is an indication that your car needs attention of some kind. Tires should be checked for irregular wear as well as tire balance to help determine the possible cause and correction of the vibration. Uncorrected tire vibration, could lead to excessive tire and suspension wear.
Q. Can out-of-balance wheels and/or tires cause premature wear on the tread life of my tire?
A. Absolutely!! An out of balance wheel or tire can rob your tires of thousands of miles of tread life.
Q. What is the difference between Static and Dynamic Tire Balancing?
A. Static balancing only checks tire balance up and down while dynamic balancing measures the heavy spots both up and down and inside and out. Dynamically tire balancing is much more comprehensive than static and ALL radial tires should be dynamically balanced.
Both are done on a wheel balancing machine that spins the wheel and tire assembly at high speeds while the computer diagnoses where the heavy spots. To balance the tire, weights are used to counteract the heavy spots.
Q.When should wheel balancing be done?
A. Tires and wheels should be balanced when new tires are mounted on wheels for the first time and anytime a tire is dismounted from a wheel. Balance should also be checked at the first sign of vibration or as we like to call it, a "shimmy". Tire balancing should also be done whenever there is unusual tread wear as both can be a sign of misalignment or mechanical problems
Q. How often should I rotate my tires?
A. Regular tire rotation promotes more uniform wear for all of the tires on a vehicle. Generally most manufacturers recommend every 10,000 to 15,000 KMs between tire rotations but check your car owner's manual for the manufacturer's rotation recommendations.
Q. How do I know when I need new tires?
A. A good indication that you need new tires is if you hydroplane when it rains and/or your car does not get up to speed at the first sign of snow.
Many tires have tread wear indicator bars molded into the tread. When the tread is worn down to where you can see a solid bar of rubber across the width of the tread, it is time to replace the tire.
Q. Must I replace my present tires with the same size tires?
A. Generally you should replace your tires with the same size or approved options as recommended by the auto or tire manufacturer. Of course there are always exceptions and safe ways to install different sized tires that original.
Q. Is it safe to repair a flat tire?
A. Yes and No. Repairing a flat tire all depends on the nature of the flat. Punctures in the tread up to ¼ inch are most often safe to repair provided the overall tire wear is still in good condition. If the damage is to the sidewall or very close to it, your tire is most likely unsafe to repair and will need to be replaced.
Q. What are Speed Rated Tires?
A. Some high performance tires have speed ratings. Speed rated tires will generally have a softer tread to aid in traction and a rigid sidewall that increases the performance characteristics of the tire. The softer the tread, the quicker the tire wears. Technically speaking, speed rated tires are designed to be stable up to and at the rated limit and range from Q being 100 mph all the up to Y being 186 mph.
Q. If I have a car that I store in the winter, can that hurt my tires?
A. Yes. If the car is stored through the winter with the tires having direct contact on a cold cement floor, this can cause flat and/or heavy spots in the tires. A good idea is to buy a standard 4 foot, 2 x 10 piece of lumber and chop it into 4 1 foot long parts of wood. Simply store the vehicle with a thin piece of wood underneath the tires.
Understanding your Sidewall:
What is a tire speed rating?
The speed rating tells you the speed the tire can safely maintain over time. A higher speed rating usually means you will have better control and handling at higher speeds and that the tire can take the extra heat. As a general rule, tires with higher speed ratings also handle better at slower speeds.
The U.S. Department of Transportation (DOT) set the ratings scale, shown below. But tire makers test their own tires and assign their own speed ratings. On the sidewall of every tire, you'll find one of these speed rating codes:
M Up to 81 mph
N Up to 87 mph
P Up to 93 mph
Q Up to 99 mph
R Up to 106 mph
S Up to 112 mph
T Up to 118 mph
H Up to 130 mph
V Up to 149 mph
W Up to 168 mph
Y Up to 186 mph
Z (See Below)
What does 'Up to 99 mph' really mean?
Tires with a Q speed rating can safely sustain speeds of up to 99 miles per hour. The tire may be able to reach higher speeds, but going faster than 99 mph for any length of time is not safe. The tire is not designed to handle the stresses.
What is a Z Rating?
For tires rated above 149 mph, a Z rating may appear in the size designation.
Safety and Speed Ratings
When you get new tires, choose tires with at least the speed rating your car or truck's manufacturer recommends. It's ok to move up to a higher speed-rated tire, but don't go lower.
The speeds shown are test speeds; they are not recommended speeds. Please obey speed limits.
What is a tire load rating?
Are you hauling groceries or bricks? The Load Rating or Load Index indicates how much weight each tire can safely support.
Every tire's load rating is stamped into its sidewall, usually after the words "Max Load". Sometimes this will be given in pounds (lb) or kilograms (kg), but it is often given as a rating code a number between 71 and 110.
If your tires have this code, you can use the chart below to see how much weight each tire can support. Then multiply the weight by four or the number of wheels on your car or truck. That's how much your tires can safely carry.
Along with this comes ply rating which goes on a alpha-numeric scale.
B=4ply [more commonly know as a P-metric or standard load]
E=10ply etc etc.
Only on 6ply or higher this will show up in the safety info section on your sidewall [how to read a sidewall below] most times will as 6PR or LRC which would simply be 6 ply rating / load range C prospectively.
On 99.9% of DOT approved tires the load index and speed rating will be displayed together.
Example: P225/60R16 88H
How to Read a Tire Sidewall
Trying to make sense of the jumble of numbers and letters on a tire sidewall? We'll explain!
Each of your tires has useful information molded right into its sidewall. You'll find the tire's brand, size, construction details, maximum load and inflation pressure, as well as traction, treadwear and temperature grades. The trick is knowing where to look. The diagram below will help you make sense of your tire's sidewall:
The tire sidewall shown above is an example of a popular "P-metric," speed-rated tire. "P" indicates that it's a passenger tire; "215" represents the width of the tire in millimeters; "65" is the height to width ratio; "R" indicates radial construction; "15" is the rim diameter code; and "95H" is the optional service description that consists of the load index (95) and the "H" speed rating. "Temperature A" reflects the temperature grade.
Some older speed-rated tires may include the speed symbol immediately before the "R" instead of providing a service description. A "B" in place of the "R" would indicate diagonal bias construction. "M+S" with the mountain/snowflake symbol indicates that the tire meets the RMA (Rubber Manufacturers Association) specifications for use in severe snow conditions.
The maximum load recommendation is shown in kg (kilograms) and in lbs (pounds), and the maximum air pressure is shown in kPa (kilopascals) and PSI (pounds per square inch). Safety Note: These are the maximum air pressure levels, not the recommended pressure for the tire when mounted on rims for your vehicle. The vehicle manufacturer's pressure recommendations (found on a decal on the doorjamb or in the glove compartment) must always be used when inflating your tires.
The DOT Code and Your Safety
The "DOT" letters indicate manufacturing compliance with all applicable safety standards established by the U.S. Department of Transportation (DOT). Next to the DOT letters is an alpha/numeric serial number, commonly referred to as the DOT Code, with up to 12 digits. This code provides manufacturer detail and the last 5 numbers indicate the week and year that the tire was made. For example, "1501" indicates that the tire was manufactured during the 15th week of year. We encourage you to register your tires so that manufacturers can contact you in the case of a recall.
LT = Stands for light truck application. Example: LT235/85R16
C, D or E = Load range indication for light truck applications
REIN = Reinforced
OWL = Outlined White Letters
RWL = Raised White Letters
ORWL = Outlined Raised White Letters
B, BLK, BW, BSW = Blackwall or Black Sidewall
W, WW, WSE = Whitewall or White Sidewall
XNW = Extra Narrow White Width
XL = Extra Load Capacity
references thus far:http://www.bridgestonetire.com http://www.ntbtire.comhttp://www.tirerack.com http://www.acmetire.comhttp://www.hoosierdirect.comhttp://www.rightturn.comhttp://www.wheels.cahttp://www.discounttire.ca
my own knowledge: 6 Michelin training courses, 3 Bridgestone training courses, 2 Hankook training courses & 6 years working with tires