FYI:
One of the reasons that it’s penny wise and pound
foolish not to straighten bent wheels is because bent wheels
do similar damage to your tires as do under inflated tires.
The bent wheel stretches the tire fabric in unnatural ways
causing wear and belt separation. This reduces the effectiveness
of your tire and your stopping ability. You don’t
save money by driving on bent wheels and wearing out your
tires. It’s just not cost effective.
VIP
(Very important Point): If you’re having your wheels
or tires worked on and the TPMS system light won’t
shut off, have them check your spare. Some spares have TPMS
sensors as well and have to be reset with the rest of the
wheels every time you reset the car.
Next
month we’ll look at the day-to-day impact of the law
and its advantages and exigencies.
Quick Links...
Rim And Wheel Works Homepage
Aftermarketwheels.com
BMW Car Club of America
Boston Chapter
This info-email is the second in a series of three on
the Tire Pressure Monitoring System Law, its background
and its impact on you.
The rationale behind the TPMS law.
Given that the new TPMS law regulates yet another
area of our lives, we have to wonder what the
possible rationale is for the law and what benefits
it provides. It turns out that there are two
main areas where the TPMS law saves us -
from physical injury and from financial loss.
Current research shows that 25% of the vehicles
on the road have underinflated tires.
Physical
Injury
Underinflated tires are dangerous. When your
tires are underinflated, the shape of the tire’s
footprint changes and the pressure this exerts
creates increased stopping distance. When your
stopping distance is increased, you get into
more accidents including accidents that would
have been preventable with properly inflated
tires. Low tire pressure results in the accidents
that you do get into being more severe. Among
the effects of increased stopping distance are
skidding and loss of control of the vehicle
when taking an off ramp or street curve, during
lane changes, and flats or blowouts. In some
vehicles, underinflated tires can cause rollovers.
Injuries to both the vehicles and its passenger
are increased. It’s important to remember
that even though you may be amongst the 75%
of people who keep their tires properly inflated,
the 25% who don’t could cause you to be
injured or worse due to their lack of control.
Financial Costs: Fuel
Economy and Tire Wear
Low
tire pressure costs you more than your deductible
in accidents. Low tire pressure also costs you
in fuel economy and wear on your tires.
Correct
tire pressure will improve a vehicles’
fuel economy. Fuel efficiency is reduced by
1% for every 2.9 to 3.3 psi of under-inflation
depending on which study you believe.. Either
way it’s fairly significant over time,
especially at today’s gas prices.
Underinflation
also causes tires to wear out earlier. When
a tire is underinflated it puts more pressure
on the shoulders of the tire and does not wear
correctly. Research has shows that for each1
psi drop in inflation pressure, tread wear decreases
by 1.78 %, shortening the life of your tires.
One
factor in buying tires is the weight of the
vehicle. It’s very important to have the
correct weight load for the weight of your car.
Each tire should hold ¼ of the weight
of your car plus extra for passengers and cargo.
The heavier the vehicles, the heavier the load
each tires takes. Generally the weight load
goes from a weight load index of 63 to a weight
load index of 150. That’s equivalent to
639 lbs per tire to 7385 lbs per tire. Under
inflated tires cannot carry the same weight
as properly inflated tires and therefore can
cause undue tire wear and a potentially dangerous
high speed situation. While most people know
to buy the proper size tire for their car, few
actually know what the weight load index and
appropriate speed rating is for both their car
and their driving style.
Note
that in the 1980s only 12% of all passenger
vehicles had radial tires. Now radial tires
are on approximately 90% of all passenger vehicles.
Separation of the belts from the tire causes
a loss of strength of the tire and more erratic
behavior. One of the advantages of the radial
tire is the steel belted radials. When tires
are stretched beyond the elastic limits of both
the tire fabric and the steel reinforcing cords,
the cords separate and the tire wears faster
and can create a dangerous situation. An additional
point to know is that when the radial belts
start to separate you often can’t see
the shredded tire from the outside of the wheel.
