Weight Limit in LWL #soccer-rules-2024

It was not something on our radar but there was the suggestion of raising the weight limit for LWL somewhat. Arguments for this are:

  • Making entry easier for new teams
  • Leave some weight available for more powerful kickers
  • Leave some weight available for incorporating dribblers

How do you feel about those?

  • Reduce the weight limit to below 1000g
  • Keep weight limit at 1100g
  • Increase weight limit to 1200g
  • Increase weight limit to more than 1200g

0 voters

Please provide reasons for your opinions in this thread so we can consider all arguments

Best Regards


We are thinking of going further an raising the limit to something like 1400g for the following reasons:

  • allow weight budget for camera setup
  • allow weight budget for kickers
  • allow weight budget for dribblers
  • make robots with cheaper and heavier motors more practical

As the differentiation between LWL and OL is now more in the technology than it is in the weight limit the 1400g limit is set such that most OL robots that were at RCJ Bordeaux 2023 would fit the LWL weight limit. Maybe we also need to consider renaming the leagues.

What do you think?

  • 1400g is a good idea
  • It’s too much (please post your thoughs below)
  • Increase it more (please post your thoughs below)
  • Go back to 1200g/1100g (please post your thoughs below)

0 voters

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PDF of this draft version is available here: https://robocup-junior.github.io/soccer-rules/dbscoach/increase-lwl-weight/rules.pdf

GitHub PR here: increase LWL weight limit to 1400g by dbscoach · Pull Request #105 · robocup-junior/soccer-rules · GitHub

First of all there are more options to design a robot if the weight limit is higher. It would also be more beginner friendly.

More variety, beginner friendly, more possibilities for new implementations (kicker, dribbler etc), good balance between hard and software

Raising the weight limit would really help new teams entering the lightweight league.
Especially the development of camera systems and dribblers would be much easier to achieve. And especially in in the background of the discussion of increasing the maximum power for kickers, more weight would help a lot.

There was a time where the only difference between LWL and Open was the weight limit. Both leagues played with the IR ball. At that very moment when the open league switched to a colored ball the main difference was the ball. Calling a 1400g bot still “lightweight” is probably an anachronism as the open league robots with 18cm often stay below that limit either.
So we could think about calling this league “2vs2 IR-League” instead of “2vs2 Lightweight League”.
However, 1400 sounds good to me for all the reasons posted before.


The thought crossed our minds but I think a new name would better fit with the bigger changes that seem to be lining up for 2025+ instead of right now on “short notice”.

You are right in that with a few exceptions 1400g would be enough for all the Open League bots we saw at Bordeaux this year.

Yes sure, I am just providing ideas. A change of names is better located in the “big rule change 2025”.

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the wight limitations have direct affects on the robots’ costs.
and the costs these days are very high.
increasing the wight will resolve that issue.

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Notes from 8/23 open Zoom meeting:

Q: David: explained what was discussed in this thread. Renaming of sub-leagues will be better for 2025 rule changes. 1400g was average for Open, making it easier for new teams, and discouraging teams from reusing optimized chassis.


Agreement that higher weight limit will improve hardware; could barely fit kicker and can’t have a dribbler so looking forward to rule change. and teams won’t have to worry about switching out metal screws with nylon.

What’s the difference between leagues now? David: ball type and size of robot. Also went through progression of using cameras in LWL to detect lines and goals as the move up into Open which requires a smaller chassis and more advanced work with cameras to effectively detect golf ball.

Statement that 1200g would be more prudent since raising the weight defeats the purpose of having a LWL. David: we’re moving away from light weight since it doesn’t promote more tech but rather more in material processing. How much you can fit on a lightweight robot can be counterproductive; we need to have one of the leagues to be beginner friendly. David: LWL is now a more “brutal” league since the ball can be seen instantly vs. the camera in open league; used to be the opposite when both sub-leagues used the same ball.

After the above discussions there was no opposition to the rule change!