Flyn Chris

I was just wondering why the WWII German tanks, for the most part, had front drive sprockets, where as the allies, notable exception for the Sherman, seem to have rear drive sprockets. What would be biggest factors for having them at the front or rear?

One reason I would have to guess at is you have extra crew protection with the drive train to front, but now you have the drive shaft running through the crew compartment which would seem to me to increase the overall height of the tank, not mention addition weight.

pattoncommander

Sprockets front or rear is always a big question mark. The entire M-3, light and mediums and M-5 also had front spocket drive as did the M-18 Hellcat and M-24. Advantage is direct hookup to the tranny and a bit of added protection for the tank crew. The Merkava series has the engine and transmission in front exactly for this reason. Downside from an operational standpoint is that the transmission is the first to take a hit and it does not have to be an AT round. A good solid HE strike on the tranny housing can stop a tank by jamming the gears or fracturing some of the many bearings. Also a tank running against an elevated hard surface can damage the sprockets or bend the teeth. As of the M-26, all US tanks have placed the drive units at the rear. The idler is set higher and is smaller than the sprocket, which gives it a measure of damage protection. As regards to traction, it has been stated that a rear sprocket will give better traction by the pushing of the tank as apposed to pulling with the drive train up front...very debatable. With the modern tank, the "pack" consisting of the engine and transmission are removed as one unit, much easier and faster with no propeller shaft or differential/clutch to disconnect. Design of the vehicle also enters into the picture. Most howitzer/gun motor carriages have the crew compartment in the rear (ie;-M-109). It is a design that puts the engine/tranny at the front, for easier access and servicing. There will always be debates on this subject.

Wozwasnt

Maybe it was just simpler to have the gearbox up front with the driver.

heavyaslead

Drive location also is considered with proper weight distribution and in particular for the the german heavy tanks, proper balancing of the large turret and expected recoil stability.

BiggTony

Why is the steering wheel on the left in the U.S. and why is it on the right in other countries? "Hey, how exactly is a rainbow made? How exactly does the sun set? How exactly doesthe posi-trac rear end of a Plymouth work?....it just does!" ~ <span style="color: #999999">excerpt from Joe Dirt</span></p>

DukeSedan

I'm not sure Plymouth limited slip differentials actually did work though. 

RSEA

Posi-Trac, Posi-Traction is General Motors terminology. Chrysler, Plymouth and Dodge had a "Sure-Grip" differential. If Joe Dirt said what he did, it makes some sense though, as he didn't know what he was talking about.

Oh and, Plymouth Sure-Grip rear ends work just find, especially in 4-speed, pistol grip Hemi cars.