pic: Does this meet bumper rules

We bent metal around our frame and want to know that since the wheels are now technically within the frame perimeter of the sheet metal do we meet bumper rules if the back of the bumpers are attached inline with the new sheet metal and then attached by the inner chassis

That is probably not a good idea.
The free ends of the sheet metal can technically be called the frame, but are liable to get bent or just wobble a bit during a match.

Beyond what was said above, how long are the bent ends? They look short of 8" to me.

I believe that since frame perimeter is measured by a string wrapped around the robot, it doesn’t matter how long the bent ends are as long as the bumper itself is 8".

Nevertheless, that looks too weak. The bumper rules aren’t there to limit you; they’re there to make sure the robots are safe. ::safety::

What you believe just ran smack into R26 (minimum 1/2" at each end backed), and if you have built your bumpers per your belief, you still have time to fix them prior to bag day rather than at your first event.

I agree that it looks too weak, however. You’ll want to put some backing in there. Actually, if I were you I’d try to use flanges on the next iteration–I think you could make a very similar piece that was plenty strong. Oh, and just as a note–I could see the pictured configuration rapidly ending up rubbing a wheel. Make it stronger, and bring it closer (if you need to in order to make frame perimeter length).

we’re thinking of just making it out of 1x1 and going out past the wheel and making an L shape and mounting to the top of the 1" on the inside of the tires

SO far, it’s definitely legal.

No matter how robust the connection between the frame perimeter and the bumpers, were I an inspector, I would rule that this does not constitute a robust connection to the main structure/frame.

For the record, I am not an inspector.

Edit: Especially on the corners,which is where bumpers are mandatory.

Even if it is legal my question is are you okay running it into something like a stop sign?
Don’t look at the rules being “legal” or not look at them being as minimums for safety and if you want to be “off” make the off lean towards safer.

:ahh: Looks like I have to give the manual another read-through. Thanks for the warning.

This isn’t a bumper attachment system, though. This is the frame of their robot. The rules do not require the robot’s frame be rigid or strong. This seems like a legal way to define the frame perimeter of the robot.

Now, clearly in a practical sense this is not a very robust system as it stands, and the bent pieces of metal will likely want some support behind them in order for this to be part of a successful robot frame that doesn’t immediately crumple to pieces upon impact. But it doesn’t seem like it isn’t legal.


Legal and wise are 2 different words.
With some boxing and gussets this could work fine.

It amazes me… we take one season off from bumpers and now everyone wants to cop-out :stuck_out_tongue: OP, if you just redo those pieces so they have flanges, then run some 1x1 tube from your chassis out to the sheet metal, you’ll be golden. The robot rules are there for the safety of the robots and those around them, not as constraints on your design possibilities.

One of the benefit of the Bumpers is that they protect your robot. If you want to design a crumple zone, that is your call. But, that will require you to be able to repair the robot quickly between matches (from COTS parts if you don’t want them to count against your Hold Back). Also, in the process of crumpling, it could damage other stuff in your robot.

Also, consider R2 where:

R2 The ROBOT must have a FRAME PERIMETER, contained within the BUMPER ZONE, that is comprised of fixed, non-articulated structural elements of the ROBOT.

and R23:

R23 BUMPERS must not be articulated (relative to the FRAME PERIMETER).

You might want to think about whether the design would have your Bumpers be “fixed” to the Frame Perimeter in normal game play.

In other words: The crumpling of the Frame is not against the rules. However, the crumpling of the Frame does not cause a change in the Frame Perimeter. If the Frame crumples, and an attached Bumper moves with it, then the Bumper has moved with respect to the Frame Perimeter, and could be a violation of R23.

Chassis, robot, floor, coffee stain, … I didn’t have my coffee this morning, need to find coffee machine.
Does anyone knows what I was going to post?

I’d note the “non-articulated” term used to describe the frame perimeter. “Articulated: having two or more sections connected by a flexible joint” pretty much describes those end pieces of sheet metal. I know others have mentioned them as weak, floppy and unwise from a practical viewpoint, but in my take on it, I would also include them as “illegal” as they are articulated due to the flexible nature of the corner joint.

Anyway, sounds like you are on top of it… good idea to post here and ask for advice.


It looks like you have a very rigid bearing support behind the flimsy sheet metal. Can you extend that? How close are you to the 120" frame perimeter? Reminder - you are only required to have bumpers on 8" on either side of a corner, so you don’t have to protect the middle wheel if that makes things easier. You do need to add at least 1/2" of rigid support at the edges of each bumper segment. Again, it looks like the wheel side is fine without the extra sheet metal. If you are concerned about the bumper rubbing on the bearing or axle, you can add a small relief in the plywood at that point.

I think it is getting close.

R26 BUMPERS must be supported by the structure/frame of the ROBOT (see Figure 4-9). To be
considered supported, a minimum of ½ in. at each end of the BUMPER must be backed by the

So the open side must extend the full 8" of that bumper segment. At that point it can be argued that it meets the letter of the rule with a static robot sitting in the lab. During game play bumpers are expected to stay in the bumper zone and continue to meet all the bumper rules. Keep in mind your bumpers will get hit. Hard. If the bumper gets pushed into the robot or pulled out, at that point the robot is no longer compliant. Potentially it will be disabled. You might miss matches fixing it.

Hello, this is our first post/reply…Can we go without a bumper on the front? We do not think so because the wheels are exposed…Thank you, Gobles Voltage - Team #5194


Every side of the robot requires bumpers at the corners.

I believe that Technically yes it does meet the rules but I feel like the first time it hits something it will either break (the bumpers) or bend into the tires and so you’d probably wind up needing to replace it. Constantly. So while it is legal it’s a very bad idea