Strafer Chassis Kit (No Wheels)
Meet the BYOW (Bring Your Own Wheels) version of the Strafer Chassis! This kit is purposefully void of wheels as we know what an investment mecanums are for teams and builders who have to be mindful of a budget. If you’ve already popped for Nexus, VEX, Tetrix or AndyMark mecanums, simply bolt them onto the included wheel adaptors. Check out the photo gallery for hardware suggestions on mounting the mentioned wheels to your new chassis.
From the top, the chassis looks simple, maybe too simple to be considered a chassis. Flip it over and you’ll notice the nested 5202 Series Planetary Gear Motors, all steel bevel gears, heavy duty hubs, and ball-bearings ready for some low-friction strafing action!
The motors are 435RPM - the final speed of your chassis will be dependent on the wheel diameter you choose to install but with some quick math, you’ll be able to determine it. Here’s an example with 100mm diameter wheels:
To convert diameter to circumference:
100mm diameter * Pi = 314mm circumference
To convert millimeters to inches
314/25.4 = 12.36” circumference
To calculate final RPM with 435RPM motor and 2:1 Bevel Gears:
435RPM * 0.5 = 217.5
To convert RPM to speed in inches per minute
217.5RPM*12.36” per revolution = 2688.3”/minute
To convert inches per minute to inches per second
5376.6/60 = 44.8”/sec.
To convert inches per second to feet per second
89.61/12 = 3.73ft/sec.
The bevel gears, located near each of the four corners of the chassis, create a 90° drive so that the motors can nest inside the 1120 Series U-Channel. The bevels have been battle-tested, even with brushless motors, and are extremely stout. Don’t worry about slipping as they each clamp to a 6mm d-shaft and the bores are matched to the d-profile of the shafts they mount to.
Each 6mm d-shaft is supported in a pair of flanged bearings in order to maximize the torque transferred from the motors to the shafts.
There are many options to get your chassis up and going. While the name suggests mecanum wheels, don’t let that stop you from creating a skid-steer chassis with conventional wheels. Below is a list of known compatible wheels. If you’re an FTC team, be mindful of the wheel width as you need to abide by the 18” size constraint.
Compatible Andymark Wheels:
- 4" Stealth Wheels
- HiGrip Wheels
- SmoothGrip Wheels
- 6 in. Rubber Treaded Wheel
- 8 in. Rubber Treaded Wheel
- 4 in. HD Mecanum Wheel
- 6 in. SR Mecanum Wheel
- Performance Wheels
- Pneumatic Wheels
- Plaction Wheels
Compatible Nexus Wheels:
- 4" Aluminum Mecanum Wheels
- 5" Aluminum Mecanum Wheels
- 6" Aluminum Mecanum Wheels
- 8" Aluminum Mecanum Wheels
- 10" Aluminum Mecanum Wheels
- 4" Double Plastic Omni Wheel
- 4" Double Aluminum Omni Wheel
Compatible VEX Wheels:
- Mecanum Wheels
- Traction Wheels
- Omni Wheels
Compatible Tetrix Wheels:
- Tetrix Max Mecanum Wheels