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Old 08-15-2019, 05:06 PM
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What's the practical ground load limit for a tank?


What do tank designers consider the practical limit to how many pounds per square foot of tread a tank can have before it will be too limited in the terrain it can cross to be useful? Even the tanks of WW2 were bedeviled by soft ground, mud and deep snow, and armor has only gotten heavier since.
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Old 08-15-2019, 06:24 PM
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As one datum the M1 Abrams has 13-15psi https://www.globalsecurity.org/milit...d/m1-specs.htm It was designed to be part of a quick reaction force to plug gaps and counterattack so you'd expect it to have lower ground pressure than a tank intended to ambush other tanks or be used in urban fighting. Russian tanks likely have lower psi still like the T72 which, if I did the calculations right, has 12.8psi https://fas.org/man/dod-101/sys/land/row/t72tank.htm

I think the main limiting factor isn't so much ground pressure but total weight since that will limit the bridges you can use. Civilian bridges and combat engineer bridges can only take so much and it seems to top out around 60-70 tons.

Last edited by MichaelEmouse; 08-15-2019 at 06:25 PM.
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Old 08-15-2019, 06:51 PM
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Quote:
Originally Posted by Lumpy View Post
mud and deep snow, and armor has only gotten heavier since.
Ground pressure hasn't really gone up as much as you might think, though. The M4A1 Sherman had a ground pressure of 14.1psi. The Panzer VI (Tiger) weighed more but had wider tracks giving it a ground pressure of 15.0 psi. Compare to the Abrams family of tanks. The M1 as it first came off the line had a ground pressure of 13.1 psi.The M1A1 saw it increase to 13.8 and the M1A2 pushes it up to 15.4 psi. The M1A2 added about 9.5 tons without changing the track/suspension.

Wiki's got some common ground pressures. A human male is listed at 8 psi. That's standing with both feet on the ground. One foot off the ground and you are looking at over the ground pressure of an M1A2. Rotate onto the ball of one foot while walking and it's even higher. Pile a bunch of weight onto a soldier's back and make them walk and their peak ground pressure can be much higher than even the heaviest of tracked vehicles. Guess who else has mobility issues on battlefields that are marked by soft/muddy ground and snow?

Mostly I've seen tracked vehicles target that range of the examples in the first paragraph. I don't recall seeing it in any design specification. To misquote Oddball in Kelly's Heroes - "I just rode 'em baby. I don't build 'em." Total weight has other issues that can't be gotten around by just spreading it around with a bigger track. Bridges are prime example where weight is a much bigger deal than ground pressure.
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