Constructing a Geartrain

example of lego gears

Gear trains are really REALLY helpful. If you're a serious Mindstormer, then I guarantee you have used gear trains and that you'll continue to use them extensively. I've mentioned them a lot in some of my other pieces, but I felt like the topic merited it's own post.

Gears are classified by the number of little ridges or "teeth" on them. Common Lego gears include the 8t, 16t, 24t, and the largest: the 40t.

Constructing a gear train is all about ratios. If you mesh an 8t gear with a 40t one, you'll get an 8 : 40  or 1 : 5 gear ratio. (This also happens to be the highest ratio attainable with only two Lego gears).

Compounding gears will help you increase power or speed though. This is best explained with the diagram below:

Combining gears along the same axle will help you gear up or down, increasing power or torque as you do so. Remember that the more torque you get, you're sacrificing that much speed, and vice-versa. It's important to establish the ideal ratio for whatever bot you're creating.

Once you've mastered this, you can work on implementing numerous gear trains in the same system, a topic I've covered here.