In our last newsletter, we published about the cause of supply issues on a national scale and more specifically with heavy duty aftermarket parts, brake drums and rotors (which is what we know best). In the previous article about truck and trailer backlogs, we showed the demand for heavy duty parts is strong on the OEM and the supply chain is still constrained. Remember that a simpleincrease in OEM production by 50,000 vehicles per year requires an additional 300,000 wheel-ends or 600,000 partsfor OEM production and takes it out of supply for aftermarket parts.
Surprisingly, when we reviewed the truck tonnage data, we found that tonnage is lower now than it was in 2019. Considering reports of great economic figures and considering product shortages, we expected to see data showing truck tonnage at an all time high. Tonnage indicates the amount of goods transported, but not mileage. It is possible that mileage is higher given the current inefficiencies in the supply chain — however, obtaining current freight mileage data was not possible. The other explanation is that freight totals are lower but significant inflation is driving most of the GDP growth. Based on the truck tonnage data our interpretation is that demand for heavy-duty aftermarket partsactually may have decreased slightly. However, supply chain issues are causing significant price increases which most people probably view it as increased demand.