Tires

The DOT code is required by law so it must be stamped on the tire. If the tire is retreaded it may have more than one DOT code. This code can be found just above the bead area on the lower portion of the sidewall and is prefaced by the letters "DOT". The letter size is small but larger than the warning text size. The date of manufacture is usually the second or third set of numbers (four digits placed together). The preceding numbers indicate manufacturing location and lot. If you still can't find it stop by any tire dealership and they can point it out to you.

There are many things to consider when specifying low profile radial tires. The lower profile provides greater lateral stability, lower deck heights, improved treadwear, and reduced weight, all at generally lower cost than standard aspect ratio radial tires.

However, low profile tires will rotate faster than standard tires negatively impacting fuel economy if the drivetrain is not modified to account for the RPM change. Generally if the tire's RPMs increase by more than 3% then the gearing and transmission will require adjusting. It is important to also look at the effect on your speedometer, engine and rear axle ratio. Low Profile tires also are more susceptible to sidewall damage. It is not recommended to mix low profiles and standard tires on adjacent drive axles since the smaller diameter on one axle can put undue load on the other. Consult with your local commercial truck dealer for recommended practices for retrofitting trucks with low profile tires.

All tires have a DOT code that indicates the date and place of manufacture. The date is a four digit number code indicating the week and year of manufacture. Goodyear’s technical manual has an explanation of the code format which I have copied below or you can follow the link for a downloadable version of the entire manual. Goodyear Technical Manual

“Tires with a Department of Transportation (DOT) number ending with 0100 or later were manufactured after 1/1/2000. 0100 is the 4-digit production date in week-week-year-year format. 0100 means the tire was produced in the 1st week of 2000. Prior to January 2000, a 3-digit date code was used following a week-week-year format. thus, 019 means the tire was produced in the 1st week of 1999"

The majority of set-back axle trucks are seen in regional haul applications in order to take advantage of the sharper turn angle enabled by this design. The disadvantage to this design is that more weight is located in front of the axle which increases both the lateral and drag forces transferred to the tire. All of which contribute to accelerated wear relative to a standard axle placement.

Another reason could be that regional service trucks tend to experience more scrubbing/curbing than a typical line haul service which increases wear issues if the proper tire is not specified for the application.

There has been a slight downward trend in the popularity of Low Profile 24.5 casings. Data collected by Modern Tire Dealer on the most popular radial medium truck tire sizes shows that tire shipments of 295/75R22.5 have declined from 11.7% of all shipments in 2000 to 10.5% of all shipments in 2003. While the statistics show a decline in use Low Profile 24.5 casings, this size is holding steady and is still in the top 5 casing size purchases for radial medium truck tires. You don’t need to worry about availability anytime soon.