Power, ground pressure, and strategic lift
Horsepower per tonne is only the tactical half. Getting there is the rest.
Power-to-weight
A useful rule: 20 hp/t is sluggish, 25 is adequate, 27+ feels alive. Abrams and Leopard 2 put 1,500 hp on 60–67 t (~22–25 hp/t). T-80U’s turbine on 46 t is a sprinter. Challenger 2’s 1,200 hp on 64–75 t is the other end. Acceleration off a hull-down position matters more than top speed.
Ground pressure and the mud
Wide tracks (T-34, T-80) float on rasputitsa. Narrow tracks on a heavy hull (early Tiger) dig graves. Ground pressure in kg/cm² is the number logisticians watch in spring. Deep fording kits and snorkels (Soviet specialty) are a different kind of mobility — operational surprise across rivers.
Strategic mobility
A tank that cannot cross a European Class 70 bridge, fit a rail loading gauge, or fly in a C-17 is a regional weapon. This is why 48-tonne T-90s still appeal, why France kept Leclerc near 57 t, and why the U.S. is trying to walk the Abrams back from 70 t on the M1E3. The best tank on a map is the one that arrived.