Counterweight / Flywheel

I’d like to see a Vex counterweight in the 250g-500g range. Ideally, it would be a steel disk (2" or 3" dia x 0.25" or 0.5" thick) with mounting holes in its face and an axle hole in the center to allow using it as a flywheel.

If it is too costly to cut a 1/8" axle hole in the center, then at least provide a clearance hole in the center, and provide suitable flanking holes to mate the weight to a 60t gear, 84t gear, or bar lock.

Back-of-the-envelope calculations show that 2"d would be about 100g per quarter-inch thickness and 3"d would be about 225g per quarter inch thickness.

Sell them in 4 packs.


  • Dean

That’s a very interesting idea that though it has been needed, I would have never thought of. Usually, i have seen people using the baterie packs as weights, as well as the large wheels.

Yeah, that would be a great idea to get counterweights. In the past I have used batteries as weights, but I never thought that other people had the same problem.

“Center of Gravity Considerations” are Paramount. :wink:

See the Inventor’s Guide, Chapter 2, Pages 27-31 (IG 2-27, 2-31)

Personally, I think you shouldn’t use counterweights. It may help stabilize your bot, but it also makes it slower and puts more stress on the motors. It’s always better to change the wheels around or change the center of gravity in some way.

My #2 adage, “Use the Right Tool for the Job.” Counterweights are a last resort. Engineering should be about solving problems, not creating future ones.


Be careful about blanket implications that counterweights are last resorts. Sometimes they are the best of a long list of possible solutions.

Remember what a typical tower crane looks like? :slight_smile:

A tall tower anchored to the ground with an arm balanced at its top. The arm is long on one side; is short and counterweighted on the other side; and can almost always rotate in a horizontal plane. Few or no guy-wires are required to stabilize the tower and the crane fits fairly easily into crowded urban environments. They look ridiculously tall and flimsy, but when properly installed and maintained, work just fine to lift heavy loads.


That is where the Experience Part comes in. After weighing the options, counterweights are the Best Solution.

The ones up the air, or laying on the ground??

ouch that reminds me of the month python scene :smiley:

anyways, IMHO couterweights are not always a last resort, sometimes they could be used as a very unorthodox method of slowing down the robot if there is not room for an advanced gear train, plus it is preferred to use counterweights on arms and other mechanisms

look at some telescopes (the hobby versions :rolleyes:) they have counterweights even though they could have a gear train, although that would affect the precision of Long and Lat and all the other weird angles in astronomy

Vex should sell them eventually but it is not a priority at the moment

I agree, while counterweights are probably not a priority - they would definitely be useful for balancing the loads on a crane or arm.

Having a balanced load on a crane or arm actually helps to decrease the load on the motor and geartrain. If the structural load of the crane or arm is balanced then more of the motor power is available to lift an object.

I’m not so sure the OP was talking about static counterweights. Flywheels are completely different. Model Railroad locomotives use them to push a train over a short dead spot in the tracks. I could easily see them used in Vex robot designs to keep a robot moving more smoothly, or to provide a smoother movement for an arm.