When creating reversible bumpers, I saw that some teams purchase a kit from robopromo.com, however, I know that some teams also make their reversible bumpers from scratch. I was wondering which ones way would be the most effective. Thanks!
2815 ran reversibles in 2013, and 4901 did in 2014. It’s not hard if you have someone that can sew and paint your numbers on the bumpers right-side up.
2809’s white paper was always my guide: https://www.chiefdelphi.com/media/papers/2437
With my team we did not buy the bumpers from the site we made it by ourself. It worked great but the only flaw was that a few staples would come off but it was no big deal. The bumpers were still efficient quick to change and did not cause us a lot of trouble.
We had no problems using reversible bumpers (we have used them the last three years). If you can sew them and have a stapler then you can follow guides or just think through how to do it.
Awesome, thank you so much!
Be careful with robopromo, due to a lack of team members but a desire for reversible bumpers, we bought a set from them. The problem is they were too big, so when using a 2.5" pool noodle, the velco on the top or would be covered. This wasn’t a defect either. When we called them up they said they were designed to use 2.75" pool noodles. If you’re considering buying them, don’t. Just make them on your own and safe yourself some trouble.
We used reversible bumpers for a few years - just figured out how to do it ourselves. You need an industrial sewing machine though or something close. The normal bumper material is pretty tough.
Note that many good teams do not use reversible bumpers. They prefer the use of material with a lower coefficient of friction and they wrap it as tight as possible.
While this is not exactly a reversible bumper design, this is what my team has done for the last 2 years and we have loved its efficiency.
We build a set of bumpers with these screwed into the wood and sew the tops of those snaps into the cloth so we can snap the cloth cover on and off. We just make a set of red and blue cloth covers and call it good.
The snaps are much more durable than the velcro most use for reversible bumpers and take almost as little time to change out* (less than a minute by 1 person to switch colors).
*Can be done by hand but is easier with a hammer
We have seen multiple teams with reversible bumpers get penalties for coming unvelcroed in a match and showing 2 colors at once, but we have never had any issue like that with this design.
I’ll look into that design since we do not have a sewing machine- thanks! I heard about the ill-fitting bumpers for robopromo.com from another team, so that’s why I’m skeptical about them. Thanks for the input!
Just a reminder to make them look nice. Like I have said in the past, if you put a lot of effort into making a great looking robot, why muck it up with ugly bumpers.
This is where we preach about bumper score, right? Yeah, right here.
Bumper Score is not a real thing, in that nobody gets a trophy for that. But it is a subtle proxy for the build quality of the rest of your robot, since everyone has to build the same bumpers (more or less). If your fabric is tight, your numbers are pretty, and the mounting reasonably quick, you probably sweated other parts of your robot about the same. If your bumpers are a mess of staples and stitching rework jobs, flop around a bit when installed, and take 30 minutes and disassembling half the robot to change, few alliance captains are going to hold out hope that you’ll be able to go rounds in playoffs.
We have used RoboPromo the last few years. Not saying that teams can not do it themselves if you have the tools and know how and time. However we found these guys to be easy to work with and they have always gone above and beyond for us. Mike has spent the day after kickoff for the last few years working with rookie teams at either our rookie quick build or at one on the other side of the state, teaching teams exactly how to build bumpers hands on sending them home with one bumper at no cost to the team so they could make the other three. They have also released on youtube video tutorials on how to build bumpers. We built bumpers for years on our own and learned more than on trick on building from them. One thing we found out last year was covers not fitting, only to find out that the 2.5 noodles we bought were actually not 2.5 as stated on the box or the sellers website. Once we got the correct noodle size (paid a bit more) everything fit correctly.
All pool noodles are not created equal. Mike has tried for several years to convince FIRST to legalize bumper-filling closed-cell foam pieces that would be better suited to protecting FRC robots from high speed collisions. HQ has resisted, probably because they (correctly, IMO) believe that neither Mike nor any single supplier should be the only source for a robot part. The supposed advantage of pool noodles is their general availability. One big advantage of an FRC-specific bumper-fill would be uniform size, which would make standardized bumper cover patterns feasible.
edit: +1 to the post below. We made reversible bumpers for a couple of years, but stopped doing that in favor of better fitting bumpers that slide out of pins more easily. We make one set red and a second one blue, then buy Robopromo slip covers in each color. Typically one set stays on the the comp 'bot and one on the practice 'bot, unless the comp 'bot suffers some bumper damage.
I would highly recommend using bumper covers, if you have someone on the team who can measure the sets correctly. They make switching between sets a breeze, without the worry of coming undone if good fasteners are used - with plenty of options available, from velcro to snap clips.
Just a tip if you use velcro, make sure your bumpers aren’t too close to the ground and watch where the hook side will hang. It could get caught on the carpet, and depending on the size, completely stop your robot movement.
I’ll look into that as well. We wanted to look at other bumper options, becuase last year we made two sets of bumpers, but our T-Nuts kept falling out.
I’ll look into that as well- thanks! We made two sets of bumpers last year, but out T-Nuts kept falling out, so I am trying to look into alternative options.
We’ve always made reversible bumpers, but I do custom upholstery for a living so it’s kind of a given. We’ve always made our own so I can’t give you any advice on the ones you buy, but hopefully I might be able to give some advice on the rest of it.
First, if you plan to make your own, use the most heavy duty machine you can get your hands on. Use at least a size 16 needle (the higher the number the bigger the needle) and upholstery thread (T70 or higher if you can get it)
Second, invest in a pneumatic stapler! This is vital. Harbor freight has one fairly inexpensive. It takes 1/2" crown and only does staples (no brads). This is important because the wider staples hold the material better without tearing it. (You’ll see wider staples on upholstery for that exact reason) You will find the stapling easier with the pneumatic, and you can adjust the pressure if the wood is hard to staple. I suggest 90-100 psi to start. You will not have to push on the stapler to get the staple to go in so it is also easier to hold the material and staple at the same time.
Third, after you put your T- nuts in, on the inside (the large flat end should go towards the your pool noodles on the inside) put a staple next to it in such a way that it won’t spin. Typically the cause of most T-nuts falling out is that they have been loosened by over tightening. Don’t use a drill to tighten bolts (I know ridiculous. Ok, just be careful to not over tighten).
Fourth, if you’re going to use velcro, be sure to put it across the entire legnth of the board. Don’t just put it in spots. (We’ve always used velcro and haven’t really had a problem)
I know the kids on my team really like the reversible bumpers because the ease of use.
If you need any help or anything feel free to pm me.
In the past few years: bumper damage means robot death, which in turn means alliance death.
Bumpers should never be an after-thought, and I hope none of 148’s future alliance partners cut corners on their bumper construction.
I’ve never met a bumper cover I trusted.
I’m always nervous reversible bumpers will reverse themselves, mid-match.
-Do yourself (and your partners) a favor, build a Red Set, and a Blue Set and switch between them.
-Build them as a “single rigid frame” style. Use that 20 lb “fastener” allowance.
-Make sure when they’re mounted they’re not going anywhere.
I encourage every team to over-build their bumpers such that they are “rock solid” during matches.
YMMV… Good Luck!
I agree with this guy.
However, I have to point out this:
-Build them as a “single rigid frame” style. Use that 20 lb “fastener” allowance.
Is HIGHLY dependent on the Person at HQ who drew the straw for QA for the day it gets asked about.
It is HIGHLY dependent on the opinion of the LRI at the event you are at.
It is HIGHLY dependent on the student(s) and mentor(s) who are present for the inspection and describe the “robust and rigid mounting solution” instead of a “steel backed bumper” or “fabric clamp” or whatever other nonsense has come about for the year.
In short. This particular bumper rule sucks. I hope it is being addressed this year but I’m not convinced it will be and we will have yet another year of silliness with bumpers and mounting hardware.
But I totally agree with this JVN guy. He’s pretty smart.