Here are some motors and gear solutions, lets start with what was shown in the video from the Russian manufacturer:
These gear were prone to failure and have been replaced meanwhile with.....no gear at all, direct drive connection to the axle of the drive wheel is now Russian standard. It also proves that some vital detail like the so called "Vorgelege" is completely missing.
This pictures shows the direct drive system of an improved 1/4 Tiger 1 that got a complete new suspension system because the original one from Russia was too weak and made the tank a low rider...


Old parts replaced :

Follow the cuts of the lower hull and you will find that the GRP is partly fiberglass enforced pressed wood and has air bubbles/gaps.
To see more of the quality of the tanks made in Russia check out this link to a German forum where they improved a 1/4 Tiger 1 from Alexej Shlakter
http://35009.forendienst.de/show_messag ... id=4740179
Here some other solutions:
This guy used motors and gear from power drills !
Then there are wiper motors from cars used....

2 Motors and separate gear for each side shown here with plastic parts used (they can break and need replacement...)

Finally a picture of our solution for a 1/5 full metal Tiger 1 built years ago, industry standard hi torque motors with a gear that drives the drive wheel. Exactly the same style like the original and sturdy!

This might give you an idea why some products are more expensive than others !
Hope this helps
Hans