German tank reliability problems were a multi-level affair that can't be pinned to any one point-but if I were to point to the biggest problems, they would be Adolf, Interchangeable Parts, and Winning The War. Hitler is a problem for tank reliability, because he likes making new tanks instead of making spare parts, and meddles to see to it that rather than repair existing tanks, they build new ones and put them into new tank divisions. Rebuilding old units doesn't excite him like making new ones does, so we get spare parts arriving at depots where they are immediately seized by armed parties from armored divisions. Your tank breaks down? Good luck finding the part you need, thanks to Hitler. Next is the nature of the parts themselves-like the British and the Soviets, German parts aren't really identical enough to swap between tanks or to install without some tweaks. Not every part mind you, but enough of them have tolerances tighter in fitting than in manufacturing. So you need a proper machine shop at your repair depot, instead of just a crane-type thing to lift up heavy equipment while you install it. At the very least, you need a trained machinist who knows how to fit things together-and he would be better used in a factory than in your depot. So the very parts themselves are more difficult to install. The final point, Winning the War, is one of those things where the Nazis, being rushed, rushed weapons into production that simply weren't ready. The old myth that the Me-262 could have won the war had it arrived a year earlier isn't just false-it's doubly false because like so many other Nazi wonderweapons, it simply couldn't have been rushed into service that much sooner. Indeed, many of these weapons were delivered too soon, with too little testing done. If the Panther had had it's introduction delayed until '44 or '45, they could have caught all the mechanical issues before they became serious problems. But since the Nazis were losing the war, a wonder-weapon today that spends most of it's time in a garage is better than one that's spending all it's time on a testing range. The A4 was hardly going to win a war by terror-bombing. But dammit, they could try, and the fact that it used slave labor in the production process was, to the Nazis' a neat bonus, combining their racial-war ideals with their needs for weaponry. Not Trying Hard Enough is not something you can accuse them of in '42 onward.