| Are you saying I
can't ever exceed 55 mph?  Certainly, there are times when – while going
downhill for example –you might exceed 55 mph for a very short time. But in no case
should tires with 55 mph speed restrictions ever be run over 65 mph.
Nor can you
“save up” your speed. If you run all day in the city, at speeds that never
exceed 25 to 35 mph, that doesn’t mean that you can make the 10-mile run home on the
freeway at 65 to 70 mph. If you have to take the freeway home, you’ll either have to
slow down, or switch to a non-speed-restricted tire.
Our M726
drive radials are consistently lasting 250,000 to 325,000 miles. Should we retread the
casings for a drive or for a trailer pattern?
You’ll
have to decide on a case-by-case basis, and you will also want to rely on the advice of
your retreader. While all Bridgestone casings are designed to be retreaded for either
drive or trailer axle positions, many factors are involved.
Drive axle
positions tend to be a bit harder on tires because of engine torque, so you’ll want
to consider the number of repairs that have been made to the casing – if any –
along with your best judgement of the tire’s inflation pressure maintenance history.
And, because
drivers tend to be more sensitive about the appearance of drive than trailer tires,
you’ll want to examine the tire for sidewall ozone cracking, curbing scuff marks, and
other cosmetic items.
In addition,
if an M726 has lasted a very long time, you may also want to check your company policy on
casing age at retread time. The D.O.T. number on the sidewall of the tire will tell you
the year and week the tire was manufactured.
Another thing
that can help is checking records, especially scrap analysis records, to find out how
similar tires have performed as drive or trailer axle retreads in the past.
As a
general rule, however, you’ll probably find that you can retread your M726 radials
for drive use at least once, and for trailer use thereafter.
Our steer tires are operating at close to the
maximum specified load. Would there be an advantage to switching from our current
14-ply rated tires to 16-ply rated versions?
Frankly, no,
because it’s not the tire that carries the load, but the air inside it. The tire is
just the air container. And, since a 16 PR tire has the same dimensions as its 14 PR
counterpart, the size of the air chamber is the same. The difference is that you can put a
higher pressure – hence, a larger amount of air – into the 16 PR tire, and
therefore, it can carry a heavier load, but only at the higher pressure.
So long as
you are not exceeding the load rating or maximum permissible inflation pressure of the
tire, there’s no advantage in going to a tire with a higher ply rating. Nevertheless,
if you are near the load limit for any tire, you should probably check air pressure much
more frequently.
We’ve
said it before, and we say it again now, maintaining the correct inflation pressure is the
single most important factor in improving tire life and reducing your tire cost per mile. |
