Hello! I’ve always found bumpers to be a bit interesting, as they’re constructed differently from the rest of the robot and are a requirement to have. I’ve always been really interested in reversible bumpers, especially since my team doesn’t use them. After attending a few regionals with teams with reversible bumpers, I wanted to ask this poll. Does your team use reversible bumpers? Why or why not?
We use reversible bumpers and will continue to
We don’t use them but are considering them in the future
No thanks we’ll stick with non-reversible
We used/use reversible bumpers but might (or have already) revert back to non reversible
My team has used reversible bumpers for the past two years, and we have liked them a lot.
Depending on what style of reversible bumpers you decide to use, they can be complicated to make and require a decent amount of sewing knowlelge. But once they are made, they are extremely convenient to use and reduce the amount of things that the pit crew/drive team needs to do before heading to their matches.
If you have any questions, feel free to reach out!
The wear spread between two sets of bumpers usually lasts a season + 1-2 offseason events, especially if you use hollow core noodles.
The only thing worse than making bumpers is fixing them on the ground at champs because the fabric is torn and the noodles have compressed too much. IIRC an unintentional color flip is no longer a very harsh penalty, but it’s certainly a DNP. The potential advantage is less wear on the bumper mounting mechanism, but meh. Grasping at straws to find a “real”, “hard” advantage when the program is already structured around two sets of bumpers.
We make our reversible bumpers using robopromo reversible bumper fabric. Makes bumper changing not even something we have to think about. Sometimes we have done it in the queue or even as we are actively pushing the robot to the queue. Definitely would never change that. Just make sure to put the numbers on the right way around for both sides lol
Our team used reversible bumpers for a couple of years during a period when we had one team member particularly skilled at sewing them. The problem was, we found them more trouble than they were worth for the work they required. In the end, we just went back to two sets of quality bumpers using our own quick-change mounts and have never regretted it.
We use reversible bumpers, and also tend to have a lot of robot issues - even though we have a relatively small team it’s worth it to use time during the season to build reversibles so we have the extra 5 minutes in the pit or in queue to finish a quick fix and maybe save an RP or two.
We have used the same reversible for about 2 years, we changed the font on our new ones and we decreased some weight after STL 2023. but honestly if you don’t change your frame, which we haven’t, they are awesome. A little hard to make but they are very nice
I used to be completely against reversible bumpers but our team had a good experience with them this year. Here are some advantages I saw:
Saves time between matches compared to non-quick change bumpers. Compared to quick-change bumpers, it requires less engineering knowledge and less design time. Of course, reversibles are harder to sew, but in our case we had a student that was very skilled at that.
It requires less manufacturing precision to create one set of robust bumpers than two for the same robot. With two sets, you have to build both exactly the same, where as with only one set you can finagle things on both the robot side and the bumper side, if that makes sense. We’ve never really built two sets of bumpers that went on and came off easily. Part of that is due to not prioritizing bumpers enough, but spending time on bumpers has an opportunity cost.
Cheaper and less material to construct.
I wouldn’t universally recommend them, and of course they have disadvantages. My default recommendation would be to build two sets. But I think that they shouldn’t be entirely dis-preferred.
We have used reversible bumpers since the team’s rookie year (2014), and they have worked great for us. It does tear a bit but most tears could be resewed after a comp in ~10 minutes. I personally sewed our bumpers last year and it took about a week to do (including backups). A Big plus side to them is that you don’t have to spend time switching bumpers and you would have a harder time losing the screws to attach them.
We used them for the first time last year and love them for a few reasons. Only one set of bumpers need to be made, which not only saves time/resources, but also saves space when traveling. It’s also nice to not have to take off the bumpers besides inspection and for major repairs. Time saver in the pits/queues.
Last year we were at 6 competitions, and didn’t see too much wear on them. This year, through two regionals, it has a few tears. Nothing too major, and probably has more to do with hitting the sides of the charge station.
The only reason we’d go back to regular bumpers would be if we decided to go with a non-rectangular chassis like we did in 2014.
I should probably put what my team does. We use nonreversible bumpers and my team doesn’t plan on changing that. My team is large enough to have people working on bumpers while others work elsewhere. When the idea of reversible bumpers is brought up usually the answer is no since we’ve had no issues with nonreversible bumpers, and it would be quite the learning curve to learn how to make reversible ones. I’ll continue to dream for the day that our team tries them out because the benefits of having to make half the amount of bumpers and more time for robot stuff during comp, but for now, we’re continuing with nonreversible.
We use reversible bumpers and will continue to do so. As long as the kids continue to ask me to sew them. They love them. But it’s a lot of work. It takes me about 12 hours to sew an entire set. (Give or take how desperately quick we need them) and I’m a professional seamstress.
If you have someone willing and able and can do a good job. (Please put velcro across the entire legnth and always have the loop fuzzy side face the carpet) then most students prefer them for the reasons stated by others above.
If you want to learn how to do them, so you can see if it’s worth the trouble, there’s lots of tutorials on here to search through. It’s definitely worth the read through, if for no other reason than to be able to truly appreciate when they’re done right.
If it’s going to be a struggle to find someone to do them, or if you have to learn sewing first, and you’re trying to see if they would be “better”, you probably won’t be satisfied with the results. If someone isn’t happy and somewhat excited to try and make them, you are probably not going to get the precision and attention to detail you need in order to get them right.
When they’re done right there are many benefits to be had, but if they’re not done right, they can be extremely detrimental. So if you decide to do them, don’t cut corners and make sure you take the time to ensure they are robust and will serve you well.
We found out that puting some pile velcro on the hook side works so then it doesn’t matter if the hook is on the carpet or not. (Pile = fuzzy, hook = pointy)
We used reversible bumpers last year, and in the offseason, the flaps started to heavily fray, making it pretty difficult to keep the whole thing in place, and it didn’t really look good at roboticon
We have used revisable bumpers for 1.5 years and non-reversible for another 1.5 (switched to non reversible in the middle of last year). I would recommend using them only if you have a lot of time to spend making them perfect. A set of alright non-reversible is much much better than an alright reversible bumper, however a really really good reversible is better than a really really good set of non-reversible in my opinion.
Also important to consider, how high are your bumpers off the ground? Our first year our bumpers had quite a big amount of clearance off the ground and worked perfectly for us, however last year our bumpers had much less clearance and dragged across the ground, got caught, etc. This is what lead us to switching to non-reversible which, since they’re not as thick, had more clearance to the ground.
Here’s a link to an old post with lots of explanatory pictures from 2019 on 4829’s bumper mount system. We developed this during the Steamworks season and have used it ever since. It basically uses steel angle plates screwed to the backs of the bumpers that fit into machined HDPE or ABS mounts on the frame, with the ends of the C-sections secured by hitch pins through the mounts and angles and into the frame. It’s extremely secure when installed but can be changed in less than 30 seconds by just pulling the pins and pulling the bumpers away from the frame, then reversing that with the other bumper set. We’ve never had a hitch pin come out on the field or had a mount break. We used to cut the plastic mounts on a table saw (literally kerfing out the recesses for the angles) but now we cut them on our CNC and do the whole batch at one time. It can be adapted for almost any frame style (the pictures are of our Steamworks bot, which had a kit frame, but we do them on our 1x2 tube frames now) and the angles are usually just 4" angle irons from Lowes with one arm cut down (the hitch pins come from Lowes too.) In the pictures the angles are run downwards along the bumpers, but this year, because we needed the bumpers to be flush with the bottom of the 1x2 frame, we ran them upwards instead. Either way works the same. We’ve seen many other systems since we invented this one, but it works so well for us we’ve stuck with it.
