Originally Posted by Mountain Man
My favorite little known factoid is the refusal of America to buy the Christie suspension which allowed a tank to achieve high speeds over rough terrain. Instead, Christie was finally forced to sell it to the Russians, who used it on the T-34's.
That is not entirely correct. The US Army tested Christies original M1928 design and even though Christie was rather difficult to work with, negotiations ended with the US Army bordering one vehicle (the M1931). After initial testing, the US Army ordered another 7 vehicles, designated the T3. The tank was fast, but only had space for a two-man crew, a small gun and had very thin armour at max. 13mm. The combat value was about the same as a WWI FT-17, except that the T3 was a lot faster, but also had much thinner armour.
At this point, the US Armys relationship with the ever difficult Christie had soured to the point that the next contract for five tanks designated the T3E3 went to another company, but still incorporated the Christie suspension. A few years later, another 16 tanks were built with Christies suspension, the T4. Armour grew to 16mm, the tank now had room for a four man crew and a 0.50 cal with a coax 0.30 cal in the turret and a 0.30 cal bow machinegun. Another 4 were built without a turret.
With war approaching, the T4s were approved as Medium Tank M1 as Limited Standard item. The line was not continued, as the Light Tank M2 turned out to be just as much tank for half the cost.
I often wonder what a Sherman could have done equipped with Chiie's suspension.
So did the US Army. In 1942, a design study was made, incorporating the T4 suspension with 5 roadwheels in a Sherman M4A4. It added 1.5 tons to the tank and the suspension was not covered with armour, but was proved to be a workable solution. However, at this time the US Army was moving towards torsion bars for suspensions with individually sprung roadwheels. Such a solution was built for the Sherman and tested in 1944, but not proceeded with.
I doubt a different suspension would've made much difference to the Sherman. It might have been a bit more comfortable, but I doubt it would've been any faster. After all, the suspension of the Sherman was not its main problem.