Back in October 2018, the peeps at Daimler Vans USA identified a noncompliance with the requirements of federal motor vehicle safety standard 110. The problem boils down to P-metric tires fitted to 24,403 examples of the Metris, produced for the 2016 through 2018 model years.
When P-metric tires are fitted to light commercial vehicles rather than passenger cars, the aforementioned standard provides that each tire’s maximum load rating has to be reduced by 1.10 before the automaker can determine the maximum load ratings of the tires fitted to each axle. The subject vehicles were certified with a maximum load rating per tire of 775 kilograms (1,708 pounds) or 1,550 kilograms (3,417 pounds) for the axle.
The recall falls under the procedure described in section 188.8.131.52 of federal motor vehicle safety standard 110, thus reducing the maximum load rating by 1.1, resulting in 750 kilograms (1,636 pounds) and 1,500 kilograms (3,307 pounds). Alas, the front and rear axle values are slightly below the gross axle weight rating.
The rubber boots used for the Metris are to be operated at a minimum pressure of 2.7 bar as per specification. These P-metric tires have a pressure reserve of 9 percent and a payload reserve of 6.5 percent at a 1,550-kg (3,417-lb) axle load instead of the specified 10 percent. Considering that overloading causes excessive tire wear and even tire failure, Daimler Vans USA didn’t really have a choice but to recall the slow-selling Metris.
Be that as it may, Mercedes originally shrugged it off as inconsequential, submitting a petition for inconsequential noncompliance with the National Highway Traffic Safety Administration. The watchdog said nuh-uh, denying the automaker’s inconsequentiality petition on June 21st.
The design of the subject tires was carried out jointly with Continental according to European Tire and Rim Technical Organization specifications. The 1.10 reduction on each tire’s maximum load rating was not applied before the maximum load rating was set for vans distributed in the United States of America “due to an oversight.” The subject vans were manufactured by Mercedes between March 31st, 2015, and September 29th, 2018.
A remedy is currently under review by the manufacturer, and customers will be informed of the recall on July 25th as per the attached report. Daimler Vans USA notes that the maximum axle load rating was changed to 1,500 kilos (3,307 pounds) in series production on September 28th, 2018.