Adding Weight to the Kitbot

There have been several times where I have wanted to add weight to the kitbot (usually for a rookie team at competition) and it always seems to be a hassle where we cobble something together. Is there a good way that other teams have done this? It would be nice to have an object or set of objects that could easily, quickly, and securely be attached to a kitbot.

Most of the good solutions I can think of are more expensive. As this thread mentions just ziptieing dumbells to the robot is not ideal.

Honestly, the last couple times we’ve added weight we’ve secured dumbbells. I would not do it with a single zip tie, but give honest thought to its location and the forces it’ll see.

Though outside of tipping prevention, I’m much happier with light robots. They accelerate faster and are gentler on the battery.

Edit: In 2019, also for tipping prevention, we did add some scrap chain to the inside of a 1x2 box tube. We filled the tube with epoxy to ensure nothing could sling out.


A PVC tube or container full of bolts and screws can easily add weight, which I’ve seen many of times

Please don’t do this. Should that container open or break, those bolts and screws could end up scattered across the field. The same goes with other similar items - I’ve seen things like PVC tubes full of sand, which is just a mess waiting to happen. I saw a team drop a hundred or so ball bearings right into the middle of their robot (fortunately, very few got onto the field), and it was a huge pain for them to clean up.

Much better - threaded rod with large bolts. You can bolt it on pretty much anywhere, and larger bolts could be be up to 1 lb each, giving you a great ability to adjust it, with no risk of it creating a huge mess.


Maybe it is a different topic but if all you had is a kitbot how much would you make it weigh? It feels like there is a happy medium between 40lbs bare kitbot and max weight.

We had a trio of these beasties on the back of our robot for when we went for the high switch in Power Up, to keep our CG as low and as centered as possible. They fit inside the C Channel and were secured by four bolts and locknuts.


I never saw one break in my days, but I probably haven’t been to as many competitions as you have

Mess waiting to happen? Maybe. Likely? No probably not. Especially if its inside the frame and decently protected

I’m sure @Jon_Stratis would not have been happy with this solution, but for an offseason event in 2019, we took a practice chassis and bolted one of the power-up power cubes to the cross members (the milk crate as well as the yellow cover). We then loaded the milk crate with CIM motors from our inventory. We added some pool noodles to keep the motors from rattling around and then secured the motors into the crate by capping the crate with some scrap 1x1 tubes run through the handles of the milk crate in a cross pattern along with some spare dyneema rope lashed through the lattice of the sides of the crate.

We added a total of 70 lbs to the robot to bring the weight up close to the full 125 lb limit.

To help with driver visibility on the far side of the cargo ships, we added a lawn chair to the top of the robot, lashed down with Dyneema rope. The seat of the lawn chair covered the top of the power cube, so it actually added a second layer of retention to the load inside.

Final product:

We won the CHAIRmans award at that event…


Our 2019 robot had a “varying weight” feature where we could add or subtract dumbbells. They were bolted to the floor of the robot and also strapped for extra stability. There was some hope that one of those triple-climb robots would be in our division and look at that as a plus when alliance selection came around, but alas, we ended up not playing with any of those teams.

So, one more vote for bolted-down dumbbells.

We can conclusively state that tying in a big kettle bell with some low-budget rope falls quite a bit short of the best idea ever…


I’d start with a color wheel mechanism and work from there


The blue thing is a bench vise. I don’t recommending using this as a robot part, either.


While your team may execute this in a way that causes no trouble, some readers will see this and emulate it. Some of those will do it poorly. You will probably not be happy with another team’s robot spilling its guts all over the field and holding up the match schedule while the field is being cleaned up.

I would be concerned about the plastic crate breaking, but it’s a better solution than sand or nuts and bolts - much easier to clean up if it spills!

Teams certainly get creative when adding weight to their robots. My favorite had to be something I heard from another LRI - a chunk of concrete from the parking lot, complete with ants still crawling on it!


If the parking lot was laid prior to kickoff should the cured concrete be considered a FABRICATED ITEM constructed prior to kickoff and thus not a legal part?


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Wait, did you literally just clamp the vise to the frame (using the vice as the clamp)?


Nah, it’s COTS (concrete off the surface).


The infamous chairbot! It was actually the best defensive bot on the field.

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I, personally, did not. However, that is a correct interpretation of the engineering. :smile:

It was 2015 and no one knew what we were doing. We have lots of stories like this, and it will all be part of my FRC memoire titled “From Worst to FIRST Semi-Decent: an FRC Team’s Story”

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