Bumper Halo vs Split

There are a couple of recent threads about bumpers

Got me thinking about Halo vs Split bumpers. What are the pros and cons?
Our team has traditionally used halo bumpers. I find them a bit hard to work with, sometimes hard to seat if the tolerances are too tight. It also may have cost us a playoff match in Heartland when we were trying to diagnose an encoder problem and a student unplugged the network cable because we needed to change bumpers for the next match. So are there any real advantages to halo bumpers?

Not really. Splits don’t add any new problems but remove several halo problems, tolerance being the big one.

7 Likes

Halo bumpers need fewer attachment points to be mechanically robust. Of course that comes with the complicated dance of “get it over the robot” and snagging the attachment points on the way down…
Sewing (especially for reversible) is somewhat less complicated on a halo.

2 Likes

I’m a fan of 2 C’s. Skip the halo problems while minimizing pieces (but still having 2 sets) and having full bumper wrap.

10 Likes

Never understood the appeal of halo bumpers. We’ve always used split bumpers, but always as 2 “C” bumpers that mostly or entirely encompass the frame. While we sometimes leave a gap for access by game pieces to an intake (as we did with this year’s robot), we cover the rest of the frame perimeter (i.e., we don’t do corner bumpers). While I can see that halos are theoretically stronger than other types, it’s not really necessary versus the strength of C bumpers. We took a dive straight off the traverse bar this year and fell directly onto our rear bumpers, where the two Cs came together, and the bumpers held just fine. Of course, we also use good hardwood boards (poplar) and fingerjoint the corners, so our bumpers are probably a bit more sturdy than most. Still, even when we still used pine boards and just glued and screwed the corners, we never had a bumper break despite serious hits and falls (our Stronghold robot had these more primitive C bumpers and fell from the top of the rope climb onto them without damage, for instance.) So no real gain that I can see in using halo bumpers.
Then there are the disadvantages to halos that everyone above has pointed out (more precise tolerances, difficulty of changing, etc.) to consider. In the end, they just don’t seem to have anything that outweighs these problems. With a good attachment system (and I outlined ours in the second thread the OP links to above) C bumpers are the way to go.

1 Like

We’ve only ever done straight segments or C’s. The C’s worked well with how we’ve done reversible bumpers the last few years and have transported compactly compared to how large a halo is (we take everything in a single minivan).

1 Like

We’ve mostly done straight segments, with the exception of L’s when you have small segments on either side of an opening. We did C’s for the first time this year, and had some struggle with tolerance in getting them on/off. Would probably prefer straight segments over C’s in the future for that reason!

1 Like

Also much easier to stuff into the crate, depending on how that’s laid out.

You get about the same number of looks walking through the airport and downtown with them though.

6 Likes

At Houston Champs (I think), I saw a team where the robot was dropped on top of the halo bumpers. Unfortunately, I don’t recall how the bumper assembly was fastened to the chassis.

1 Like

I’ve never personally done halo style bumpers, but the one time I tried C-Shape bumpers I was really happy with them. Having smaller pieces is nice for packing purposes. I am generally uncomfortable with single sided bumpers. Depending on the quality of your job, flexing away from the frame can be a real headache.

1 Like

You don’t use halo, didn’t like C the one time, and don’t use single side. So you use corners?

Sounds like the Bumper Halo is getting a lot of hate. 4272 has done halo style bumpers since 2017

In my mind, its the strongest (maybe I’m crazy). It gives a continuous plywood box for other robots to hit before damaging the chassis. It also means we can get away with fewer attachment points. I think last season there were 2 10-32 bolts holding our bumpers on (several other passive points), but only 2 nuts were required to put the bumpers on?

We CNC cut our bumpers, so clearance has never really been a problem.

I’ll admit, its kind of a pain to remove/replace so maybe someday we will switch.

2 Likes

I think you may have misread. Also, to clarify, I have used single side bumpers before. I just find them more difficult to “set it and forget it”.

1 Like

For some reason I read that as unhappy with them. Long day negotiating with QA of what a requirement means.

2 Likes

1706 uses a halo style bumper. One of the advantages is that bumpers come on or off easily by 4x 1/4-20 nuts. Having a continuous surface across the robot also helps with durability. For us at least, the only time we need to take bumpers off is for inspection and if we need to work on major frame pieces. Otherwise, they are reversible and very convenient. On our off-season bot (originally from 2018) we have two c-shaped bumper pieces that we use that are reversible. I believe that it all comes down to how the bumpers are built, if you are expecting defense, etc

2 Likes

Durability is the concern my team’s advocates of halo bumpers express. I just don’t know if I have ever seen people have durability problems with 2 C’s style bumpers. I was kind of fishing for people willing to complain about their 2 C’s having issues so I would know if there was a lot of potential for issues.

We have been using 2 C’s for a while. We havent had any problems with them breaking during matches. We did have problems getting them to fit, but that can be fixed by cnc cutting the wood. We used Riv-Nuts and 1/4-20 bolts to attach them so it was 8 1/4-20 bolts to get the bumpers off. We used 2 drills and didnt have any problems with not being able to do it quickly enough

2 Likes

The only split bumper issue we’ve really had were that “identical” ones have sometimes been different enough that they have a preferred side, and so they get marked left and right. The last couple of times the same color split bumpers can’t be switched because the bumper cutout specifies which side is which.

We tried halo 2021 and they generally didn’t like haven’t to place the bumper over the top, but it does have some advantages like adding structure and potentially needing less mounting structures. But another advantage of split bumpers for us is the storage of the extra set, which fit better under our cart platform that way.

1 Like

4901 did halo bumpers in 2016. It was fine once dialed in, but that was also a very small robot.

1293 did halo in 2018 and it drove us nuts—but that robot was tall, had a flip-out intake, and wasn’t the paragon of precision manufacturing. Our people seem happier with two Cs, and considering our taste for frame gaps (2019, 2020, 2022) it’s not like we’re losing a lot of strength doing so.

1 Like

About half the times that I have ever seen a robot get e-stopped due to the bumpers falling off, it was C style bumpers (the other half were mostly the style of bumper where you have 4 straight bumper pieces that meet each other at the corners). I think I saw a C bumper come off at CMP on Newton this year, but it was late enough in the match that I don’t think they got e-stopped.

We used a Halo bumper this year, but in the past we have used other styles (2020 was 2 Cs with a cutout, 2019 was a single piece with a cutout, 2018 was corner bumpers plus small straight segments on 2 sides, 2017 was single piece with 2 cutouts on adjacent sides plus a corner, 2016 was Halo, 2015 none, 2014 was 2 Vs).

Overall, we were happy with the Halo this year, but in other years we have had issues with getting Halo bumpers on and off smoothly. So, I think it depends on the robot design whether Halo is a good choice or not.

The C bumpers in 2020 were easy to get on and off, but we used automotive (racing) hood latches to hold them on and those were difficult to get aligned and latched.

In 2017 we used nuts on studs to hold the bumper on and we ended up stripping one of the nuts at an offseason event and missed a match because of it. Since then we use wing nuts (except for 2020 where we tried something new).