With these modules you can easily construct a mobile platform that is exactly the length and width you need.
Each unit is basically one half of one of our middle weight drive train modules. It includes a 10" length of the 3/8" extruded square tubing. The tube houses a two-stage chain-and-sprocket speed reducer and a 4" wheel. It bolts right up to our E30, A28, or F30 motors. This unit is very easy to use. Just bolt it in place, plug it in, and go play!
You can easily mount these modules into your robot by drilling and tapping some 1/4-20 screw holes right into the 3/8" aluminum wall. Four screws should be enough to mount it to a base plate or frame. You can also mount your armor or other components directly to the module using more tapped holes. We left the hole locations up to you so that you would have maximum flexibility in mounting.
The extrusions are symmetrical so your motor can be mounted on either side. We call these "Type-A" and "Type-B". For a four-wheel drive robot, you would typically need two of each type. Just choose the types that you need on our order form. You can always reconfigure them if you change your mind.
Like all our kits, no chain tensioners are used in the modular drive units. The chains are so short, and the axle locations are machined to such tight tolerances, that chain tensioners are not required. Some chains start out slightly on the tight side but they loosen up once the chains are broken in. This is one of our key cost-cutting features in all our kits. We reduced the parts count and the cost with no impact on the ruggedness. We tried to heed the advice of Antoine de Saint-Exupery when he said "You know you've achieved perfection in design, not when you have nothing more to add, but when you have nothing more to take away." But we made sure to temper our enthusiasm for that philosophy with Albert Einstein's advice: "Everything should be made as simple as possible, but not simpler."
Reduction Ratios
These drive modules are available with either 5.6 or 3.4 to 1 reduction ratios, (the same ratios used in our kits.) The standard ratio uses sprockets with 9 and 24 teeth and the high-speed ratio uses sprockets with 13 and 21 teeth. To switch to the faster ratio you just replace the standard sprockets with our high-speed sprockets.
The following chart shows the robot's top speed using various combinations of motors and reduction ratios:
| | Motor RPM | Standard 5.6 Ratio | High Speed 3.4 Ratio |
| A28-400 | 4900 | 10 MPH | 17 MPH |
| A28-150 | 6000 | 12 MPH | 20 MPH |
| F30-400 | 4800 | 10 MPH | 17 MPH |
| F30-150 | 6900 | 14 MPH | 23 MPH |
| E30-400 | 5700 | 11 MPH | 19 MPH |
| E30-150 | 5600 | 11MPH | 19 MPH |
Ten to twelve MPH is plenty fast for almost any type of educational or fighting robot so we ship all our kits with the 5.6 reduction ratio. Those who have had lots of driving practice at that speed might want to try the faster ratio so we offer a high-speed upgrade.
Specifications:
Ships fully assembled with 5.6 or high speed 3.4 reduction ratio
4" wheel included
Length: 10.5"
Weight Bare: 5.1 Lbs.
Weight with E30-150 motor: 8.7 Lbs
BK-BKTMODA