8 Inch rule?????

In the rules, there has to be 8 inches of continuous length on the robot. But does that start on the bumper or the chasis? Cause if it has to have the space cut out for the ball in the middle of the chasis, does it have to start from the bumper or the chasis itself? :ahh:

There must be 8 inches of Bumper protecting both sides of every vertex (corner) of your Frame Perimeter.

does the 8" from the vertice corner mean the corner of the bumpers meeting out in space, or the 28" by 38" frame of the robot. I can find no absolute evidence in wording to support either one. Help appreciated. guess i’ll go reread the rules again::rtm::

The rules state that the bumper must cover the “exterior vertices of the Frame Perimeter”. I’m 93% sure it means 8’’ of the chassis itself.

Q. Does the 8" of bumpers required on each side of vertex include the 3" of the bumper meeting it from the connected side? Or does the bumper need to be 8" of plywood with noodle. In Figure 4-1 it appears that the upper left horizontal bumper is 8", and the vertical is 6" with no plywood on the end.

FRC3931 2012-01-24

A. Per Rule [R27], the Bumper must be at least 8 in. Per Rule [R28], the Bumper must be backed by plywood. Thus, the plywood must be 8 in. The figures in Section 4.1.6 are for illustrative purposes only and are not drawn to scale.

(emphasis mine)
I think this clarifies it pretty well. Good Luck :slight_smile:

garyv is right.

go check the official Q&A the posted answered this question several times.

(not exact wording but yeah):
A: The 8in. of frame perimeter directly next to the vertex must be covered by bumpers…

So the frame has to be 8 inches? I’m sorry, it’s just that we can’t find the exact answer anywhere.

If the plywood has to be 8 inches, I’m pretty sure there’s a rule that all of the plywood has to be supported by the frame. But I just want to double check it.

This is our case: Frame is 27 x 37, the 27 inches side has 6 inches of frame on each side and 15 inches of opening in the middle for the ball. Would we have to change both of those 6 inches to 8 inches? If so, that would kinda suck - we’d only have about 11 inches of opening.

Can u split the 8"'s up on one side? Like 5 inches on the Front on both the left and right sides?


8" from the vertex of the frame perimeter on each side of the vertex of the frame perimeter. Not 8" on the side of the robot. Not 5" on the perimeter + 3" outside the perimeter. 8" from the vertex of the frame perimeter on each side of the vertex of the frame perimeter. The configuration you are proposing should not pass inspection at any event, as it only has 5" on one side of two vertices.

Neal, I would suggest understanding the implications of [R33] as currently written, which says quite clearly that 1) bumpers must be supported by the frame of the robot, 2) as part of that support there is a maximum gap depth or width, and 3) as part of the support the ends of the bumper need to be supported (this particular item was added in Update 2, IIRC). Because of that, you will need at least the equivalent of 8" of frame supporting the bumpers. Yeah, you’d only have 11" of opening on the narrow side. So does everyone else who is smart enough to build their robots 1" undersize to avoid trouble with the size box. At least you’re not getting told this at your first regional…

We asked a question on the first Q&A and got a very specific answer. YES the bumper has to be 8" and YES the opening will be 11" or so if you load from the front/rear.

This is how I see it.

That is correct. 8 inches on each side.

Is it just me or should the GDC re-write the bumper rules so that they arent so confusing! :stuck_out_tongue:

Does it mean 8 inches for each side of the robot combined, or 8 inches on the robot in a row?

In other words, can we have two sets of 4" bumpers on each vertice (know I spelled it wrong) of our ball intake side making 8 inches total for side, or must we have 8 inches on each of the vertices?


If you drive long ways, and you have an opening for a pick up, then you have 8 inch of frame on each side of the pick. Giving you about an 11 inch opening for said pick up.

The intent of the rule and the Q&A answers that I’ve seen has been pretty clear that the 8" is measured from the vertex. That’s not 8" per side. That’s 8" from the vertex, per side, per vertex.

And on the GDC rewriting the bumper rules so they aren’t as confusing, they did, or at least made a stab at it. The problem is that they are having non-100% coverage for the first time since 2009. And instead of having a percentage as they did in 2008(?) and 2009, they specified a length from a corner vertex. The problem is that people are having trouble understanding what “at least 8 in. of Bumper must be placed on each side of each exterior vertex” means (or they may just plain want it to not mean what they understand it means).

Then again… The definition of Bumper may not be clear in that rule. Which is why the very next rule defines how to construct a Bumper, and what a Bumper is.

4.1.6 Bumper Rules
Robots are required to use Bumpers to protect all exterior vertices of the Frame Perimeter.** For adequate
protection, at least 8 in. of Bumper must be placed on each side of each exterior vertex**

Yes. Welcome to FRC.

Each vertex has two sides, for a total of eight sides. Each of these eight sides MUST have not less than 8" of bumper, backed by “something substantial”.

The least amount of bumper you can get away with is eight 8" long pieces.

Thanks for clarification, Eric. We did make them 8 inches. Now we just hope our grabber works well with 11" opening.

That would be really bad if we never changed it and they told us at the regionals.