Tread Depth 2:
Same Axle and Between Axles
This page -- "Tread Depth 2" -- is a response to a question
posed to us as a result of our original tread
depth article, about truck tires on the same axle and between
axles having the same depth of tread.
It is a guest post from
Product Development Manager,
Continental Commercial Vehicle Tires.
We received it as a result of our Twitter correspondence
Commercial Vehicle Tire Group,
Continental Tire the Americas, LLC.
Across the same axle, it should be standard practice for
all tires to
have the same rolling circumference, and this is most easily
accomplished by using the same tire specification tires matched to at
least 4/32nds of tread depth. If for some reason, an
operator chooses to run different specification tires across the same
axle, then the circumference of the tires should be matched to at least
3/4". Failure to do so
will cause the axle ends to rotate at different speeds and could
shorten the life of drive axle differential components unnecessarily.
different height of the axle ends could act on the vehicle geometry and
create the same issues as poor alignment. This additional
stress will shorten the typical service life of wearable drive line
components in steering
linkage and suspension systems.
When considering the difference in tread depth between
two axles in a tandem configuration, you should consider the reason for
that difference in the first place. Typically, the two axles
will wear at slightly different rates, and fleets are encouraged to
rotate tires between the two axles when the difference becomes greater
then 5/32nds in tread depth.
This is done mainly to maximize the life across all 4 wheel
end positions in a tandem drive axle application. This
methodology assumes that all
four wheel end positions receive new tires at the same time.
All (8) standard tires, or (4) wide base tires.
It is also possible that the different wear rate could
be attributed to reasons other than typical wear. Examples include
problems with bearing maintenance, brake maintenance, ride height
controls, and alignment. If these problems are allowed to
continue, normal deterioration of the problem will lead to unplanned
maintenance and possible safety concerns.
Of course, there are always exceptions to the standard
maintenance model. Some Fleets/Owner Operators will choose to run drive
patterns on one axle and rib tires on the other axle in a tandem drive
application. It's possible that only one of the axles are
driven, and the rib specification is sufficient for the free rolling
axle. In this case, it can be difficult to match the rolling
circumference across all (4) wheel ends.
However, please keep in mind that the individual axle should
receive equivalent diameter tires for the reasons stated above.
If you have further questions about tires, please feel
free to send
them to us on Twitter, @ContiTruckTires, or via email to
firstname.lastname@example.org. We are always glad to hear from
professional truckers and to listen to your concerns.
from Tread Depth 2: Same
Axle and Between Axles Tire
Circumferences to our Preventive
Maintenance page or our Truck Drivers Money Saving Tips