Wide chassis vs thin chassis


#1

Hello,

I was wondering what everyone’s opinions were on a wide chassis vs a thin chassis. A wide chassis has the benefits of having a wider intake so it can pick up balls easier and can likely defend better. A thin chassis has the benefits of being able to fit in the corners between flags and walls easier, park easier, and escape defense easier. Overall what do you guys think is better and what are other pros/cons? Thanks


#2

Okay - so. I had a 35 wide robot, and then a 20 wide robot. between the two extremes, I would choose the 20 wide over the 35 wide any day. However - there’s this area in between 30 and 25 holes wide that most people are generally in. This range is probably the best. It gives you enough space to build, and is also not ridiculously wide. I think in my opinion, driving even something around 30 wide is significantly easier than driving something that’s 35 wide, and although driving 20 wide was a lot easier to get around people than on 35, our driver had to drive really well to pickup the balls properly (our intake was in total around 17 holes wide). A wide chassis does not necessarily = better defense, and likewise thinner robot does not = better against defense.


#3

I think one of the main benefits of a thin chassis is that the turning radius is smaller. This means that (given enough torque) a thin chassis would turn faster than a wider chassis. If you don’t need to fit that many complicated mechanisms on your robot, I would just make it thin.


#4

ok - this is untrue. your thinner chassis will not turn noticeably faster than a wide chassis. There’s a limit to how thin you want to make your robot, before it starts entering the area of diminishing returns. Just because you can, doesn’t mean you should: https://youtu.be/qGNFWMYMqIk.


#5

While I think that going 20 wide may be overkill in terms of thinness (props for making it work), going somewhere in that range between 30 and 25 wide is the sweet spot imo as well. Going 35 wide is unnecessarily wide, as you should be a good enough driver to not need a more than 13 inch wide front intake. Going 35 wide also make you a very large target for defense, which is an ever present danger in this game. I don’t think that the turning radius argument is valid for deciding between chassis of the 35-25 range unless you for some reason have an all traction wheel drive. As a driver of a 35, 30, and 28 wide chassis robots, I can conclude that there is absolutely no difference in the feel of turning in any of these, as long as your wheel setup gives your robot a centralized center of rotation.


#6

Yeah. 30 to 25 is the sweet spot. Going less is not worth it (there’s not much detriment, but you don’t gain much), and going more has nothing added. Driving 30 and 35 against heavy defense does make a difference in my opinion - it’s noticeable. 30 and 25 though, there’s not much difference.


#7

I agree that having a thinner chassis allows you to avoid defense a little bit, but that depends on your drive style quite a bit. While having a wider chassis makes you a larger target it also makes you harder to get around, so you can play defense easier if you want.
Honestly this whole question greatly depends on your drive style. Are you somebody who is better with speed and prefers to out maneuver your opponent? Go with a thinner chassis. Do you like to hold your ground and push back against defense. Go wider, and find your sweet spot somewhere in the middle.
Now, from someone who has a 35-35, we used to have issues reach corners and tight spaces, but that was when we had a narrow roller. Now that we have a wider roller, it’s not really noticeable, and our grabbing surface is larger which makes things easier on our driver, which is the ultimate goal. The easier it is to drive the better.


#8

hmm, how wide do you guys go on your wheels?

I chain mine so the drive section is 6 holes wide each which means 12 holes are being used for just wheels unless I start building over them.


#9

Personally, I would prefer a thinner chassis. We had to have components of our robot that would exceed the size constraints if we had a 30 wide chassis, so that’s a pro. We could also reach the bottom flags SO much easier than if we had a wide chassis.
If you want a wide chassis, it means you want a robot that is essentially a tank. Based on my experience, it is much slower and you don’t need that. It depends on your driving style. Would you rather hang out in one area and score points there, or do you want the ability to move?
As for the intake, just make use of the space you have.


#10

I built a pretty cool thin robot with an H strafing drive last year. It helps you to stand out a bit if you have a really meta design. Alternatively, with defense, you’re more likely to tip sideways with a thin base. It depends on your CG.


#11

I love the width of my 35 wide ball intake. If you want a lighter and more maneuverable robot, the best option is probably to cut your length instead.

These robots are awesome examples of very wide but less long bases. The effect is a full-width ball intake but low weight and good maneuverability.

Best of luck!


#12

Okay. Guys. I keep going back to this: a thinner chassis =/= tipping sideways easier. I’ve linked a video to us trying to see where we would tip on a 20 wide robot -that’s 10".

now - our intake on the 20 wide was NOT the biggest issue with our robot, believe it or not. I would also like to respectfully (as much as is possible in the online community now), disagree with what @vexFTW said about being wide. We played a lot of matches with wide robots, and even the pilons (5225a) and wof (8825S) last season were quite wide. Being wide doesn’t drastically improve maneuverability on field, and toggling flags with a 30 wide or 25 wide should be roughly the same - it’s not going to be harder or easier on either. Being a tank won’t slow you down, a 200rpm drive will still get to ~190rpm on each pretty easily.


#13

At my competitions, if you had a wider chassis, you would have more attachments on them, which would be more weight, which would, in turn, make the robot heavier. As a result, you would be slower. I wasn’t trying to say that a standalone wider chassis was slower, just the more attachments you are (probably) intending to put on there.

If you have a wide chassis, but not much on it, then that’s more weight on your robot you don’t need.
Hope this clarified my original statement.


#14

Ah - yes this makes sense. When we went to a wider chassis, we didn’t add much more on. The total weight of our robot increased probably by about the weight it would be to make the cross braces longer. A wider robot means you have more space to attach stuff, but also means you have more space to better distribute what you put on. I think a team would be able to take a wide chassis, yet still make it fast and light (if they had plans for a thin chassis anyways).


#15

I intentionally made my chassis out of steel to add weight. It should help me against V5’s superior drive power. It’s wide, but my driving style allows it to be maneuverable enough.


#16

Agreed, we have a 35-35 and only weigh 16lbs. We are still very fast, however when all four robots are crammed in one section of the field it gets pretty challenging to get where you need to go.


#17

I like thin, so that you have room for your attachments to hang over a little bit.


#18

why would you want…attachments to hang over? What happens when you get hit?


#19

okay: i found this match from a while ago. Please review it and take conclusions about whether or not a thin robot will really help you get around the field. https://drive.google.com/file/d/1wlNpbSUAz2fD55qfYKAmhLRdRdrocOds/view?usp=sharing


#20

I mean that you have room for something like a claw to pick up an item outside the base instead of inside the base.