Things You Should Know About Tires

Tire Pressure

·       Check tire pressure once a month, the leading cause of tire-related crashes is under-inflation & a leading cause of premature tread wear is under-inflation

·       Check tire pressure when tires are cool to the touch for most accurate measure

·       Never overinflate, consult your manual and/or the driver side door/frame for the proper tire inflation levels.  Overinflation is the second leading cause of tire-related crashes

·       If overinflated use pin to push metal stem in middle of valve down until some pressure is released

·       Be sure to note your tire pressure in your Electronic Glove Box

Types of Tires

·       Hard tread – enhances tread life and fuel economy but diminishes traction in both dry and wet conditions

·       Short, stiff sidewall construction – enhances cornering protection and directional stability but takes away from ride quality

·       Wide tread w/ minimal grooves – enhances grip during dry conditions but detracts from grip during wet and snowy conditions

·       Aggressive open tread – enhances snow traction but aggravate tire noise and sacrifice tread life on pavement

Tire Balance

·       Proper balance will keep your tires from uneven wear and provide a more comfortable ride.  It is a good idea to re-balance tires at each tire rotation.

Tire Rotation

·       Rotate tires every 6-8000 miles (or more often if the driver’s manual dictates)

·       Make a note of each tire rotation in your Electronic Glove Box

Wheel Alignment

·       Check alignment when you hit something substantial, you see a wear pattern developing on the inside or outside of your tires, or you notice a difference in handling/steering.

Tire Tread

·       Excessive or uneven tread wear may be a sign of improper inflation or steering and suspension misalignment

·       Look for cracks or bulges on sidewalls before road trips, if spotted replace tires

·       If worn to the “wear indicator bars” replace tires immediately (always replace in pairs of 2 or 4 at a time)

·       Replace tires if tread wear is severely uneven

·       Insert a penny upside down into the tire groove. If you can see the top of Lincoln’s head your tread is too low

Tire Temperature

High tire temperature leads to a lower tire life.  The following lead to increased tire temperatures:

·       High speeds

·       High loads

·       Under-inflation

·       Coarse pavement

·       Aggressive driving

·       High cornering

·       Hard braking

 

When buying tires, understand that tire selection is a balance between ride quality, noise suppression, fuel economy, wear, load capability and cost. You should discuss these issues with the tire-store expert to select a tire that is the right balance of each for your you.

 

Understanding Tire Labels

Example: P195/60R16 63H M+S (see definitions below)

·       P - Type of tire (P = passenger)

·       195 - Width of the tire across the tread in millimeters

·       60 - Aspect ratio of the sidewall compared to the width

·       R – Construction (R = radial)

·       16 - Diameter of the rim in inches

·       63 - Tire's load rating

·       H - Tire's speed rating (H = 130 mph)

·       M+S - Tire is suitable for all-season driving

 

Types of Tires

·       P = Passenger Vehicle

·       T = Temporary Tire (Spare

·       LT = Light Truck

·       C = Commercial

·       ST = Specific Trailer Service

·       No Letters = European Cars

Construction

·       R = Radial (98% of all tires)

·       D = Diagonal for light truck or spare tires

·       B = Belted (practically extinct)

·       RF = Self-supporting run-flat tires

Load Rating

·       Generally range from 60-110

·       The higher the number, the more carrying capacity 

Speed Rating (Max Speed the tire is designed for)

·       L = 75 mph

·       M= 81 mph

·       N= 87 mph

·       P= 93 mph

·       Q= 99 mph

·       R=106 mph

·       S= 112 mph

·       T=  118 mph

·       U= 124 mph

·       H= 130 mph

·       V= 149 mph

·       W= 168 mph (Exotic Sports Cars)

·       Y= 186 mph (Exotic Sports Cars 

 

Why does tire pressure need to be checked monthly?

Tires are made of “permeable” rubber, meaning they are NOT totally air-tight. Oxygen (air) slowly leaks through the rubber over time.  During hot weather (summer), the permeable rubber expands and allows more “air” to escape, therefore in the summer, you should check your tire pressure more often.  On the other hand, in cold weather (winter), less air escapes through the contracting permeable rubber, HOWEVER, cold weather causes the pressure of the air inside the tire to contract….which also causes tire pressure (PSI) to be reduced and therefore cause UNDERINFLATED tires.  For each 10º drop in temperature, tire pressure (inside the tire) will decrease 1-2º…. So consider how dangerous it would be to not check your tire pressure in 3 months during a hot summer, then a cold front blows through, reducing the temp by 40º…..  your tires could easily be under-inflated by 20º and that is very dangerous and expensive in terms of tire wear, fuel economy and your safety.

 

Just so you know

Some auto service facilities now offer Nitrogen to fill your tires.  The reason for this is that Nitrogen (N2) has a larger molecular size than Oxygen (O2), meaning each N2 molecule is larger and therefore has a harder time escaping through the permeable rubber.  O2 permeates approximately 3-4 times faster than does N2 through a typical rubber tire.  So you may want to consider using Nitrogen to fill your tires.

Don't be intimidated by an auto service technician that is "trying to SELL you a service". 

Prepare and educate yourself to have an informed discussion at the Auto Service Shop.

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