Bumpers for swerve

What are the best bumpers to use for swerve?

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While there are lots of opinions on bumpers, corner bumpers are probably the least regarded. With swerve drive, just covering the corners (i.e., the modules) is probably a bad idea. In our more recent seasons, the importance of defense and the impacts involved have become much greater than they used to be. Having most of the frame covered by good, properly secured bumpers has become imperative. Corner bumpers are less protective and much more difficult to secure well. So I’d say go with C-shaped or single unit bumpers as your best bet.


I was thinking heaviest and not shape because swerve bots always seem to be tippy especially if you’re not square. I guess it really depends on the rest of the bots cg though

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We have always done reversible and we swap between 2 C shape pieces to get the off and on quickly when we have a tall bot, or a single continuous piece when we have short bots. But reversible has been non-negotiable for us as it works well for all of our competitions. We tend to cover all sides of the bot and leave none of the chassis exposed since the last time we did that we had to replace the chassis rails twice in the same season from being so badly bent. We are considering using solid continuous from now on since at our first event this year they were ripped off twice due to higher speed impacts from swerve of swerve hits. We ended up changing our mounting and still had an issue in one of our matches at DCMP.

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Ive seen tippy swerve bots and tank bots with super low cog, and ive seen tippy tank bots and super low cog swerve bots. :person_shrugging: Swerve is easier to have a lower cog since a bare chassis will weigh more then a bare kop or wcd chassis.


One piece.
Maximum weight.
Tight, smooth, and slippery.

And make them look good.


FYI, there’s a gotcha for bumpers on Mk4i modules:

If you want a gap in your bumpers, you’ll probably be forced to mount them to the top of the module itself. That’s because the Mk4i modules are ~7" wide, which is longer than the minimum bumper length from a corner. The good news is that the Mk4i has some (#8) tapped holes which could be used for the purpose, but they may not be the most convenient depending on your frame design. It would be nice if you could carry the plywood or mounting structure further than the noodles and fabric, but a recent Q&A ruling made that (inexplicably) illegal.

It was kinda meant as a joke

Next time we’re in the same place (THOR maybe?) come check out our bumper mounting system. We use a machined bracket and pin system that has never failed us, even when we’ve taken some huge hits and big falls (like that dive from the traverse bar straight onto the bumpers at 2022 DCMP.) We use C-shaped bumpers too, though not reversible since the mounting system is really easy to take on and off, and we do always cover as much of the frame as possible, with maybe a minimal opening if needed for game pieces.

Any chance you could share details/picture(s) of your bracket system?

Any chance you could share details/picture(s) of your bracket system?


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 when we had a through-the-frame battery mount and we had to get the bumpers on and off a lot. It worked so well we’ve 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 secured by hitch pins through the mounts and angles and into the frame. The angles rest directly on the frame exterior, so no slop, but it also gives the wood about 3/16" clearance all around which let’s it flex slightly. Since we use hardwood boards (poplar) that are finger-jointed, glued and screwed at the corners, the bumpers themselves are pretty tough but have a good flex. The whole system is extremely secure when installed but can be changed in less than 30 seconds by just pulling the pins and sliding the bumpers away from the frame by about an inch then lifting them away, then reversing that with the other bumper set. 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 router and do the whole batch at one time. I’ll see if I can find the CNC file and post it (not sure where our machinist has it socked away.) It can be adapted for almost any frame style (the pictures are of our Steamworks bot, which had a kit frame, but it works fine on a 1x2 tube frame too) and the angles are usually just 4" angle irons from Lowes with one arm cut down (the hitch pins come from Lowes too.) We’ve never lost a pin or had a bumper come loose during a match, no matter what happens to the robot (serious collisions, falls, etc.) We’ve seen many other systems since, but this one works so well for us we’ve stuck with it.

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