In my recent reading about my home country during WW2, I noticed that we sometimes used steel tracks for our tanks due to rubber shortages - Canadian Dry Pin tracks, and I've had trouble finding specific, cited information on these things - how well did they perform in use? Were there significant differences in combat performance between tanks with CDP tracks versus traditional rubber tracks? If so, what were these differences, especially in terms of performance in different types of terrain (specifically, I am most interested in performance in snow and on rough terrain/without roads)
Thanks in advance for any information you can provide.
Edit: Apologies for the typo in the title.
According to Canadian trials, CDP tracks could be expected to last for 1200 miles in severe conditions and 2000 miles in favourable conditions on tanks (Ram and Grizzly) or 1500-2500 on the lighter Sexton SPG. British results were much poorer, but that was because the track was installed backwards during trials. Trials were held again with the track the right way. I don't have details on these second trials, but later documents comment that were much more successful. Tracks would start stretching much earlier (for instance, one Sexton was stopped after 1252 miles), but it was possible to remove a handful of links and carry on. Other trials also showed that ~1200 miles was a more realistic lifespan estimate. For instance, after 1154 miles of running on a Sexton (479 on road, 675 cross-country) an inspection showed that the track pins were in good condition, but the links themselves were heavily worn, both the contact surfaces and the track pin eyes. A number had developed cracks. 8 track links have been removed up to that point. Canadian tests with Ram tanks showed that the lifespan of the tracks was comparable to that of American style tracks, and unusual wear on the drive sprocket was not observed.
A clear advantage of CDP tracks was that they were lighter. A full set of T54E1 tracks weighed 3520 kg, a full set of CDP tracks weighed 2086 kg.
In combat, heavy idler wear (chiefly on Sextons) was reported. This was because mud would pack on the inside of the track and stress the idler bearing. The metal track links were also tougher on the rubber rim of road wheels and idlers (doubly so for synthetic rubber) than rubber coated tracks. To combat this, three Ram tanks with CDP tracks were tested. One had a sprocket with longer teeth to prevent track jump, which allowed the track to be loosened. The other two tanks were not modified. When run through heavy mud, the control tanks broke after 14 and 18 miles respectively, while the improved tank drove for 150 miles of heavy mud ("soft mud, high sand and gravel content, hard bottom") without trouble. The sag did not seem to impact performance at all. Crews felt that their tanks could go where Shermans with steel chevron tracks could not. However, the Shermans had one advantage: they could fit Extended End Connectors, which improved their flotation characteristics, while Sextons that used CDP tracks could not.
By May 4th, 1945, it seemed that these tracks were still considered acceptable in heavy mud. Instructions for field conversion were distributed to the troops "for use when terrain causes a necessity".
Sources:
P. Samsonov "Sexton of the God of War"
P. Samsonov "Sexton enters the fight"
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RG 24 C 2 reel C-5777 slide 1668
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