The tank was given its nickname "Tiger" by Ferdinand Porsche, and the Roman numeral was added after the later Tiger II entered production. This was a problem on the Eastern Front in the muddy rasputitsa and winter weather conditions. It was expensive to maintain, but generally mechanically reliable. It was also difficult to transport, and vulnerable to immobilization when mud, ice and snow froze between its overlapping and interleaved Schachtellaufwerk-pattern road wheels, often jamming them solid. The Tiger was prone to certain types of track failures and breakdowns, and was limited in range by its high fuel consumption. While the Tiger I has been called an outstanding design for its time, it was over-engineered, using expensive materials and labour-intensive production methods. Only 1,347 were built between August 1942 and August 1944. Production was phased out in favour of the Tiger II. The Tiger I gave the Wehrmacht its first armoured fighting vehicle that mounted the KwK 3688-mm gun (not to be confused with the 8.8 cm Flak 36). Its final designation was Panzerkampfwagen VI Tiger Ausf. Tiger I was a German heavy tank of World War II deployed from 1942 in Africa and Europeusually in independent heavy tank battalions.