"Report on KV-1S Road Wheels
Kirov factory KV-1 tanks used cast road wheels with Г-shaped rims. As a part of the total requirement for weight reduction, the weight of the road wheels would be reduced by changing the shape of the rim. A T-shaped rim was selected, which gave the same robustness at less weight.
Two of the first KV-1S tanks produced at the Kirov factory, #15001 and #15002, with T-shaped road wheel rims, ribs, and round openings in the disks were provided for trials.
During trials at factory #100, tank #15002 traveled 2027 km, and tank #15001 traveled 2025 km. No road wheels were destroyed and no cracks were found. One intact road wheel on tank #15002 was replaced due to a destroyed ball bearing. Currently, both tanks are kept at factory #100. They have traveled additional distances during trials of other components. The road wheels are still intact.
Trials of the tanks finished on September 9th, 1942.
The first mass produced KV-1S tanks were completed by the Kirov factory on August 23rd, 1942. The Kirov factory installed road wheels that were different from the road wheels used on tanks ##15001 and 15002. The disks and rims were thinner, the openings were larger, and had a different shape.
Military QA had to choose: accept no tanks at all, or accept them with the new wheels. A decision was made to test the robustness by striking. The robustness turned out to be sufficient, and the tanks were accepted.
Reliability trials performed at factory #100 in late October to establish the warranty period using KV-1S #15126 showed insufficient mechanical robustness of the accepted road wheels. Over 1007 km of trials, 7 road wheels were lost. The tank was removed from trials on November 4th, 1942.
The Kirov factory's design bureau replaced the road wheels with a reinforced design as a result of these trials. The trials of the replacement road wheels have not been performed yet. I approved the blueprints for the road wheel between October 29th and November 3rd, 1942. These road wheels were installed on tanks from August to December.
Senior Assistant to the Chief of the 6th Department of the GABTU BTU, Engineer-Major Voroshilov.
December 15th, 1942"