Hi All - Given that the new bumpers cannot have a 45 degree edge. Has anyone thought about designs for reversible bumper colors?
I know some teams swear by them, but given all the hits they’ve taken last year, and who knows about next year yet, having 2 seperate sets that, in theory, take half the hits each, seems like a good idea.
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Is this in reference to the wood backing? Every time I’ve made reversible bumpers they’ve always had 90 degree corners. The only difference is in how the fabric is sewed together. What rules make reversible bumpers more challenging to build?
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I assume they’re talking about 4 separate segments and having the 45 degree bevel on noodles and the fabric cover.
We’ve done our reversible bumpers where each bumper is C shaped and the reversible portion wraps end to end instead of top-down. That way the corner construction also doesn’t really matter as far as the reversibility is concerned.
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This is also how we did ours when we did them and as a bonus they held up better to scratches because, well… there’s more fabric there.
We had reversable bumpers from 2016-2022 and never used mitered corners. Here are 2 examples:
I wrote a whitepaper 2 years ago covering color changing bumpers (and a lot more construction info)
https://www.chiefdelphi.com/uploads/short-url/wi0CmFAIUyxIOHWRYbRI8Pl54U0.pdf
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Context? I haven’t seen anything about a bumper rule change? 
Like this:
Yeah. I’m not sure how mitered or non-mitered corners affects that strength of the bumpers. I will say that having reversible bumpers is likely the only way we will ever go.
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We posted about reversible bumpers previously. Reversible Bumper Instructions Available Here
New rules don’t seem to impact doing them in 4 segments like this.
*A square robot would have 2 long and 2 short bumper segments. Each segment being reversible individually.
I see, I missed that one.
As a team that uses reversible bumpers, after reading through this, I don’t anticipate any significant changes to comply with these rules, the main difference will just be that the bumpers are uglier because of how the corners have to be. Our pits/cart is already cramped enough without adding a second set of bumpers to it.
Also, maybe it’s just me, but in the last several years of using reversible bumpers, we’ve never had any issues with bumper robustness aside from minor fabric tears and numbers coming off, and I’d like to think we play at a high enough level to be able to tell. Is the bumper robustness issues people are having perhaps just a problem of there being a lot of teams building their bumpers wrong/badly in the first place?
We build one piece bumpers every year as we feel they are stronger and better at protecting the most important parts of the robot. We have used the same shock cord method for tension since 2013 and have never had a bumper failure since. Some years sewing is better than others, but we recycled the fabric from last years set and ran them for 2 seasons total (129 matches + practice and scrimmages so far) with only minor tears and a few noodle replacements.
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I did this YouTube video several years ago on how you do reversible C-bumpers. Our team also uses the end-to-end version of them, since that gives you a continuously sewn cover with no unsewn edges at the corners.
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A lot of teams are seeing more bumper damage and frame damage where the bumpers are weak. Beyond pool noodle degradation, I think it depends a lot on how you build your bumper frames, how well supported they are, how heavy your bot is and how long your season is. 4 segment bumpers are much less likely to sustain plywood damage, but they don’t necessarily offer as much protection as 1 piece. A really solid tube frame will take the load from lower quality bumpers without the plywood deforming much, etc.
We use 1 piece bumpers with very strong glued plywood corner joints and a 80-90lb bot. The only thing that takes much wear is the noodles, but we have lower energy collisions due to weight, and our bumper frames are made from baltic birch and structural epoxy.
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I spent some time last summer on bumpers 
The takeaway from using this method was “oops, I should have tested with canvas, not bedsheets”… It turns out that you need at least one open corner for a non-reversible full bumper. A reversible up/down bumper cover needs one open corner on the fixed part and two open corners on the flip.
Thanks so much, @Patrick3357! I’ll be looking at these for construction this year!
@cbale2000 - FIRST released bumper rule changes for 2025. The document is located here.