Bumper "Side" Clarification

The rules read

ROBOTS are required to use BUMPERS to protect all outside corners of the FRAME PERIMETER.
For adequate protection, at least 8 in. of BUMPER must be placed on each side of each outside
corner (see Figure 4-3). If a side is shorter than 8 in., the entire side must be protected by
BUMPER (see Figure 4-4).

I have attached what we are currently hoping is alright and the drawing most closely describing our situation from the game manual. We are thinking that the end of our chassis would constitute a side and therefore the whole thing must be covered by bumper. It is shorter than 8 inches though and we are concerned that the bumper still must be 8 inches. We don’t think that we will be forced to extend our bumper given that there will be no frame chassis or support after that 5 inches in the attached picture. This is an issue because if the bumpers have to be 8 inches the robot has to be 26 inches wide to intake a ball not over a bumper.

The bumper needs to be at least 8" long. You need to support it, as shown in the rules. Your idea of having short bumpers like that (which has been asked about by countless other teams) won’t pass inspection. Sorry.

There might be another way to get the BOULDER in there…think about it…

And just to reiterate, the side with the opening still has a frame perimeter of 24 inches. The calculation of the frame perimeter doesn’t required a actual frame.

If this is a top view, the edge of your FRAME PERIMETER is the 24 inch dimension and therefore you have to cover 8 inches on either side. The bumper shown would not be legal.

See this Q&A

If in doubt, imagine pulling a string all the way around the outside of your robot. This defines your FRAME PERIMETER. Each of the sides of string now needs to have at least 8 inches of bumper on it, and each end of each bumper piece needs to be supported (at least 1/2 inch per R26).


To further clarify for you, as shown in the diagram, you have only 5" of bumper protecting the frame perimeter…the 3" outside the frame perimeter does NOT count towards the 8" required::safety::

The manual drawing you have attached is clearly just like your planned robot. You’ll note the black rectangle drawn on it marked FRAME PERIMETER. The FRAME PERIMETER is the thing that has sides that need to be covered. In the manual drawing, the short bumper on the side with the U cut in it is at least 8 inches long. Your bumper must also be 8 inches long because each corner of the frame perimeter must have at least 8 inches of bumper on either side of it.

In short, your CADed drawing is illegal because the bumper needs to be at least 8 inches. And yes, this does mean your robot must be 26" wide to intake a ball through the bumpers.


I edited your CAD image to show what you’d have to do to follow the bumper rules, if you were to keep a width of 24 inches (see attached). You are correct in saying that the gap between the bumpers is not wide enough to fit a boulder. But, as you said, if you increased the robot’s width to 26 inches, the gap would become 10 inches, which is the diameter of a boulder. Hope that helps.

R19 states: If a side is shorter than 8 in., the entire side must be protected by BUMPER (see Figure 4-4)

The way I read that, is you are allowed to have a side less than 8" as long as the entire side is covered by a bumper. I could be wrong about the way I am reading that part of R19.



A side with a gap in the middle isn’t considered 2 sides. It’s one side and the gap can’t be more than 8 inches from a corner on either side.

The side is not just the part with the frame. The side of your robot includes the opening for intake. Therefore the side is not 5 inches. It’s 24 inches. Which means 8 inches from each corner must be covered.

EDIT: In the image this highlighted part is the answer to your questions.

Before anyone suggests it, no, tilting/turning those short bits of frame on either side of the U cut-out won’t help. It will create a new shorter side right where the cut-out is. The two corners of that new side will need 8" of bumper as well, further covering up the U cut-out.

The picture from the manual that was posted with a gap in the frame does NOT have 5 sides. It has 4 sides. A side goes from corner to corner, not from corner to gap.

So does the 8" of bumper have to be continuous? Or if you had a 4.5" section of bumper, then you use the Rhino bumper kit to have the rest of the 3.5" of bumper raised, would that still count as your 8" of bumper coverage?

These balls are pretty squishy. You could get them through a **much **narrower passage if needed. (That said, we’re lifting the ball over a continuous solid frame perimeter, using a gap in the bumpers to help keep things tight and low.)

I don’t see anything forbidding this. Bumpers are not required to all be at the same height, or even horizontal along their length. However, given the hardware required to mount this, it would probably be easier and lighter to raise the whole corner.

I guess no one figured out why the maximum bumper height is 12" this year…sigh…

Yes we did, shhh :wink:

A hard lesson from 2012 :slight_smile:

The legality of non-horizontal bumpers seems contradictory with the rules others are stating. It implies that it is legal to have an 8" vertical bumper, attached to an 8" vertical frame member at the corners, which fits within the 4" and 12" vertical envelope. Does anyone else see this configuration as illegal? If this is legal it allow for a much wider center gap for those doing something in the space between the bumpers.

While the Blue Box below R19 doesn’t explicitly apply to your situation, it would stand to reason that the 8" of bumper cover still have to be along your Frame Perimeter, and your Frame Perimeter does not go vertically. It’s a question for the Official Q&A, but it somewhat goes against the intent of the rules.



Yes probably a Q&A question. I guess it depends on the definition being used for perimeter, some dictionaries state it means the 2D shape as if looked at from above but others make no distinction and count following a line around all outside edges (3D) including a vertical portion of the edges as being pat of the perimeter. But this may also count as being another ‘side’ of the robot.