occasionally section repair radial wide-based tires that could wind up on the
steer axle of a local delivery truck, such as a dump truck or a waste hauler
truck. We think our repairs are done very well, but would you do a section
repair in a tire for steer axle use?
I would not put a tire on the steer axle of a truck if it had been section
repaired. The reason is not because I think the repair would not hold up, but
if the tire was to have any kind of failure, and the vehicle was involved in an
accident, the blame would fall on the repaired tire - even if it had been run
flat - because someone shot a hole in it. It would not matter why the tire
failed, the blame would be placed on the section repair.
We are finding a small-molded triangle at the end of the
date code marking on some of the casings we receive for retreading. It only
shows up on some of the casings with a three-number date code and never on the
ones with a four-number date code.
This triangle means the tire was manufactured in the 90's. At that time, having
the triangle was not required, so you will find some tires manufactured in the
90's that do not have the triangle. Since all tires manufactured today are
required to have a four-number date code, the triangle is no longer used.
I move my retread plant to a different location and keep my same DOT plant
Yes, you can. Just send a letter to Jeanette Greenfield, Office of Vehicle
Safety Compliance, 400 7th St. S.W., NSA32, Washington, D.C. 20590, and give
your new address and current DOT code.
recently read that NHTSA has released a new report on new and retreaded truck
tires. It is over 200 pages, and I have not had the time to read it. Is it good
news or bad news?
The NHTSA report that was released in January 2009 basically presents
information regarding retread performance that has been available for years.
Most of the information comes from a study conducted by the University of
Michigan that confirms that most rubber on the road is the result of poor tire
maintenance; not retreaded tires.
are the advantages and disadvantages of widebase tires and traditional duals?
There are four factors to consider: fuel economy, weight, availability, and
tread life. Here's how each stacks up: Fuel economy: Compared to standard
compound tires on steel wheels, widebase tires on aluminum rims would probably
offer a fuel economy advantage. Compared to tires with "fuel
efficient" tread compounds on aluminum rims, the wide base tires may offer
little or no measurable advantage. Increased revenue: A vehicle that reaches
its weight limit before reaching its cubic capacity limit can benefit from the
fact that four wide base tires on aluminum wheels weigh less than eight
conventional tires on steel rims. The reduced vehicle weight means more cargo weight
can be carried. Most interest in these tires has come from bulk haulers.
Mixed-service applications have been the slowest to adapt since durability and
retreadability issues are so vital to their operation.
should I check the lug nuts 50-100 miles after the wheels have been installed?
When dual wheels are installed the bolted joint that encompasses the stud,
hub/drum, wheels, and fastener is going to flex as soon as the axle is loaded.
The initial flexing results in joint settling that can cause the wheels to
become loose. By checking the lug nuts after the first 50-100 miles of service,
any joint settling that has occurred can be corrected by tightening or
replacing the fasteners.
should I pay extra to properly repair a flat tire when plugging is so much
Unless you have xray vision any damage on the inside of the tire cannot be
detected when plugging the tire on the rim. By removing the tire from the rim,
inspecting the interior, and repairing the damage with a rubber stem and a
repair unit, the integrity of the tire can be restored or potential problems
can be identified. Proper tire repair also protects the casing so the tire can
either be retreaded or returned for credit.
there an age limit to casings?
The simple answer is no. You cannot determine the retreadability of a casing
based solely on age. Air pressure maintenance, the number of repairs, and the
number of retreads also play important roles so the age is just another
component of the inspection criteria. In fact, most truck tire manufacturers
have at least a 5-year warranty on their casings, yet it is not uncommon to see
the life span of a well maintained casing in the correct applications perform
beyond that time period.
it legal to repair a steer tire?
A steer axle tire with a puncture repair in the crown area that is 3/8" or
less in diameter can be repaired using a rubber stem and a repair unit. If the
injury is larger than that or in the shoulder or sidewall the tire can be
repaired with a section repair but it cannot be returned to the steer axle.
run fully loaded but come home empty. What can I do to reduce irregular wear?
You can reduce your tire air pressure based on the load/inflation charts,
however you must be very careful to increase the air pressure when you are
running loaded. Most fleets feel that this is an unsatisfactory and not a
practical solution since it leaves the door open to low tire pressure if you
forget to reinflate. Unfortunately, there is no other way to reduce uneven wear
in this scenario.
my air pressure be what's listed on the sidewall?
The air pressure listed on the sidewall is the recommended air pressure for the
maximum tire load. The maximum tire load is also lsited on the sidewall. To be
safe, most drivers will inflate their tire to this level. But, if you want to
get the maximum life out of your tire and you know your actual tire load, then
there are load/inflation charts which can help you determine recommended tire
air pressure. A good online reference chart can be found at:
http://www.goodyear.com/truck. Click on tire information to download an
are there speed ratings on some medium and heavy-duty truck tires and not on
Tires that may be used in Europe will generally have a speed rating or symbol.
In the United States, with a few exceptions, the only truck tire with maximum
speed ratings posted on the casing will be local use tires, such as tires for
dump trucks, concrete mixers, etc.
the tread design is worn off the radial truck tire casing with a maximum 55 mph
rating, is it legal to operate it at a higher speed after it has been retreaded
with light, high speed tread designs?
I do not know of any law that addresses this, but it is not a good idea. The
heavy-duty casing would likely become overheated and fail, if driven at high
there a federal law regulating the minimum allowable tread depth for truck
Yes, the federal law on minimum tread depth for truck tires is 4/32 inch on
front axles and 2/32 inch on other wheel positions.
there any situation where plugging a hole in a tire and not using a patch would
be an acceptable industry practice?
Not according to tire manufacturers. Using a plug without a patch is a common
practice for repairing tires that are not used on public roads because
repairing a tire on a lawnmower, slow moving farm tractor, and similar types of
equipment appears to present little risk. With that in mind, I would still
recommend that the tire be removed from the rim and inspected before repairing for
the safety of the tire technicians.
would it be acceptable to inflate a tire to the maximum pressure?
With truck tires this is a common practice because of the heavy loads they
carry and the fact that most heavy-duty trucks do not have a placard in the
vehicle that recommends a specific inflation pressure. The tire manufacturers
and the tire and rim associations have a chart that recommends the correct
inflation pressure for the weight that the tire is carrying. The inflation
pressure for passenger tires is designated on a placard or owners manual in
there a federal regulation requiring trucks to use new tires when hauling toxic
No. There are no federal regulations that require new tires to be used on any
are new to the retread business in our country and we wish to know how old a
tire can be and still be retreaded or repaired.
There is no simple answer to you question, as in most cases a tire is rejected
for retreading or repairing not because of its age, but because of its
condition. Many tires may be unacceptable for retreading when they are only a
year old, while others may be perfectly acceptable for retreading when they are
close to ten years old. It all depends on how well the tire is maintained and
how and where the tire is used. Some environmental and operating conditions can
destroy even the best new tires very quickly.
I have to remove any information from a truck casing before it is retreaded?
do I go about getting a DOT Code for a new retread plant we are opening?
Contact Janet Greenfield of the DOT at (202) 366-5317.
the DOT Code on retreaded truck tires have to be molded on the tire sidewall or
can it be branded into the sidewall?
It is a very common practice to brand the DOT Code on retreaded tire sidewalls.
Make sure you don't brand too deep and the brand should be as close to the bead
as possible. It is also a good idea to place the brand near the original DOT or
any other DOT retread codes.
recently purchased a retread plant. Do we have to apply for a new Department of
Transportation (DOT)code, or can we use our old one?
The DOT may allow you to use the same code, but you must notify it of any
change in company ownership or address. Contact the United States DOT at
can I tell if my passenger tire is a retread?
There are standards for passenger tire retreading that require the DOT code and
"R" (along with the additional identifying information) be stamped or
branded on the sidewall of all passenger retreads manufactured or sold in the
will 20 percent overinflation in a steel radial truck tire affect the tire's
It depends on how the tire is used and the surface it is used on. If the tire
runs on a smooth surface, it will likely develop some irregular wear. If it
runs on gravel or travels over rough surfaces, the tire will likely experience
severe cutting, chipping and other impact damage. Wet gravel makes the cutting
and chipping worse. We recommend using only the inflated pressure required for
the speed and load.
you recommend destroying a casing that may be dangerous to mount and inflate,
even if it belongs to your customer?
We think it is a good idea, but your customer may not agree. It is the
customer's property, so get his or her permission before destroying a casing.
mark our truck retreads with "R-DOT" designation along with our
additional company information and the date. We just learned that we should not
put the DOT symbol on our tires. Is this correct?
The "DOT" symbol is for use on passenger retreads. Truck tire
retreads should be marked with the "R" symbol only. The Department of
Transportation regulates only passenger retreads.
new tires imported into the United States for sale, required to have the name
of the manufacturing country on them?
Yes. United States Customs requires that all imported products have the country
of origin permanently marked on them.
understand that the maximum allowable injury for a nail hole repair in a large
radial truck tire is 3/8"(10mm), but I don't understand why a
3/8"(10mm) injury in the sidewall requires a more costly section repair.
The tread area of a medium radial truck tire features four to five layers of
steel cord-three to four belt plies and one body ply-while the sidewall has
only one steel body ply. Given those features, the tread area is heavily
reinforced so that the repair unit for a 3/8"(10mm) puncture really only
has to seal the injury. The sidewall offers much less reinforcement and flexes
more than the tread, so it calls for the extra support of the larger unit
required of a section repair.
it true that any irregular tread wear pattern that develops in an original new
tire will show up again when the casing is retreaded?
An irregular tread wear pattern is usually caused by operating conditions, the
tread design, or poor maintenance of the tire or vehicle. The tire casing has
very little effect on tread pattern wear.
the new ultra-low profile truck tires that replace duals be retreaded?
Definitely. Both manufacturers have successfully operated retreaded tires in
was told that I should not mark my truck retreads with the DOT symbol, but
instead should use the "R" to designate "Retread". Is this
true, and why?
In your case, the "R" designating "Retread" (along with the
additional required identifying information) is sufficient because there are no
standards for retreading truck tires. On the other hand, there are standards
for passenger retreading that require the DOT code and "R" (along
with the additional identifying information)Contact TIA at 800/426-8835 for a
copy of the DOT Part 574-Tire Identification & Recordkeeping requirements.
it acceptable to use bias ply tires on the front of my dump truck if radials
are on the tandem drive axles?
speed-rated passenger tire casings retain their speed rating after retreading?
As far as we know, most domestic manufacturers do not recognize the speed
rating of a passenger tire retread.
is minimum dual spacing measured?
Minimum dual spacing is measured from the centerline of one tire in a dual
position to the centerline of the other tire.
perform free air pressure checks for truck drivers on a regular basis. We know
that any tire with less than 80% of the recommended inflation pressure must be
deflated, demounted and inspected before it can be returned to service. What do
we do when a hot tire is underinflated but above the 80% threshold?
According to the Rubber Manufacturers Association/RMA, underinflated hot tires
above the 80% threshold should be inflated to the cold inflation pressure plus
10psi. Once the tire cools to atmospheric temperature, the inflation pressure
can be adjusted to the correct level.
regrooved tires be used on the steer axle of a dump truck?
Yes. The only type of vehicle with restrictions on steer tires is a bus. A bus
cannot be operated with regrooved or retreaded tires on the front axle, but
other vehicles can. (TRIB does NOT recommend the use of regrooved
tires on steer axle of any vehicle)
long does a truck have to sit before the cold inflation pressure can be read?
Generally, the cold inflation pressure can be recorded after the vehicle has
been parked for at least 3 hours.
do you measure dual tire spacing?
Dual tire spacing is measured from the centerline of the outside tire to the
centerline of the inside tire.
is the maximum air pressure for seating the beads on a truck tire?
According to Occupational Safety and Health Administration (OSHA) Regulation 29
CFR 1910.177, the maximum tire inflation pressure to seat the beads is 40 psi
in a safety cage. OSHA sets the maximum inflation pressure to seat the beads
outside a safety cage at 5 psi. (Used with permission from
TireRetreadingRepairingTODAY, July 2002)
know that temperature changes have a direct effect on inflation pressures. What
For every 1,000-foot increase in altitude, there's a 0.5 psi increase in inflation
pressure. So a tire that starts in Denver inflated to 100 psi will read around
97 psi at sea level and a tire inflated to 100 psi at sea level will read
around 103 psi in Denver. In other words, it doesn't have much of an effect.
know the minimum tread depth allowed on steer axle truck tires is
4/32"(3.2mm) and the minimum for drive axles is 4/32"(3.2mm). What is
the minimum tread depth allowed on lift axle tires?
The answer is 4/32"(3.2mm). The regulation doesn't mention lift axles or
drive axles, but it states that all tires other than steer axle tires must have
many repairs are acceptable in a standard tubeless radial truck tire?
The number of repairs is unlimited, as long as the repair units do not overlap,
and the same radial body cable is not injured more than once.
am aware of some new truck tires that have been imported into the United States
without a production date code. Can these tires be sold in this country? They
have an ISO 9002 marking, the letters "DOT" and a two-letter
manufacturing plant designation.
The Department of Transportation (DOT) states that any tire without a
production date code and the complete DOT marking requirements cannot be sold
in the United States. The ISO 9002 designation does not require testing of the
tire and is not a substitute for the DOT code marking.
what point will a truck tire burst from overinflation?
Most new or undamaged medium radial truck tires can withstand three to four
times the recommended pressure before bursting. In fact, the rim usually fails
before the tire. ITRA has conducted several burst strength tests on new and
used medium radial truck tires with special reinforced rims. The tires were
pressurized with water. Most recently, three new tires and 13 used tires were
"burst tested" with the lowest pressure burst recorded at 300psi and
highest at 540psi for an average of 420psi. All of the test tires failed in the
do I know if my tires are suitable for retreading?
Only your retreader can make that determination after your tires have been
inspected in the retread plant. Tires that have been run underinflated or have
been pulled with less than 4/32" of tread left are more likely to be
rejected than tires that have been properly maintained and pulled with
5/32" or more tread remaining. This is, of course, a good argument for
properly maintaining tires. Before the retread process begins all tires are
subjected to both a visual inspection and an inspection on a non-destructive
testing machine (there are several equally good systems now in use). Only those
tires that pass this stringent inspection are allowed to continue through the
retread process. For more information see: "Every Retread is Custom
Made" in Tires A-Z.
many times can a steel radial truck tire be retreaded?
That depends on the condition of the tire and how much damage it has
accumulated. Long haul, high-speed operations usually retread their tires two
or three times. While fleets, such as garbage hauler and other local service operations
that wear tires out very quickly, can sometimes retread their tires five or
more times if they are properly maintained.
are affected more by underinflation, radial or bias truck tires?
The extent of underinflation and the speed and distance the tire ran are
factors to consider. Also, underinflation affects tubeless and tube-type tires
differently. In fact, it causes so many conditions we think it best to state
that underinflation causes damage to all tires and should be avoided. We do not
recommend any tire as being better than another when run underinflated.
are the regulations regarding the use of retreads on steering axles?
This is an issue that confuses many people. A misconception exists that
retreads are not allowed on the steering axle of any vehicle. The fact is,
retreads can be used on the steering axle on any vehicle with the exception of
a bus. Paragraph "d" of the Federal Motor Carrier Safety Regulation
Title 49 Part 393.75 states, "No bus shall be operated with regrooved, recapped
or retreaded tires on the front wheels."
type of nail hole repair does the best job, one, or two-piece?
If properly applied, both types work extremely well, but there is a difference
in how the two can be used. A one-piece repair is appropriate if the angle of
the penetration through the tire does not exceed 25 degrees. A two-piece repair
can be used regardless of the penetration angle. When a single piece repair is
installed with the stem angle at greater than 25 degrees, the stem often breaks
off at the patch.
heard that before mounting a commercial truck tire that may have been run low
or flat, it must be inflated to 20 psi above the recommended inflation
pressure. Is this true?
The Rubber Manufacturers Association (RMA) recommended practice states that any
tire suspected of having run low or flat must not only be inflated in a safety
cage to 20 psi over its recommended inflation pressure, it must retain that
pressure for 20 minutes. It must then be lowered to the recommended pressure before
being returned to service.
am new to the service business. Recently, while deflating a 1200-24 truck tire
the stem became clogged and I used a piece of wire to clear it. It was a warm
day, but I'm sure I saw ice or frost in the stem. Am I correct?
Yes. We can imagine your surprise when small chunks of ice came out of the stem
when you inflated the tire on a warm day. Air forced through a small enough
opening at high pressure works much like a freezer - it begins the icing
process. Sometimes the stem even frosts on the outside.
a company operate multiple retread plants under one Department of
Transportation (DOT) shop identification code?
No. Each physical location must have it's own DOT code.
know that underinflation shortens a tire's life. Does overinflation do the
It depends on the type of tire, vehicle speed, travel distance and the surface
it travels on. Overinflation can cause irregular tread wear, poor handling
characteristics and severe impact and cut damage, on rough or rocky roads.
Check with your vehicle manufacturer and tire supplier for their
recommendations for your particular situation.
surface wears a tire faster, a wet or dry surface?
If the tire is free rolling and not slipping, a wet surface lubricates and
cools the contact area of the tire, thereby causing it to wear at a slower
is the origin of the word rubber?
Believe it or not, in 1770 an English chemist named Joseph Priestly created the
word "rubber" when he found the material could remove pencil marks