To ascertain if this were true the Allies attempted to estimate the number of Panther tanks being produced. To do this they made use of the serial numbers printed on captured or destroyed German tanks. The principal numbers used were gearbox numbers, as these fell in two unbroken sequences. Chassis and engine numbers were also used, though their use was more complicated. Various other components were used to cross-check the analysis. Similar analyses were done on tires, which were known to be sequentially numbered. The analysis of Panther tank wheels yielded an estimate for the number of wheel molds that were in use. A discussion with British road wheel makers then allowed the estimation of the number of wheels that could be produced from this many molds. This in turn yielded the total number of Panthers that were being produced each month. Analysis of road wheels from the two tanks obtained yielded an estimate of 270 Panthers produced in February 1944 alone, substantially more than had previously been suspected.