Long vs. Wide Drivebase

Is your team going with a wide or a long drivebase?

Not Tippy
Longer base takes up more room on bridge

Takes up less room on bridge


Anything else?

tippy tippy tippy. If you’re going over the bump, or even over the bridge, you almost always have a large chance of tipping.

Largest bumper gap for a ball intake?

well you can only pick up 3 balls at most…

If you want to be picked for elims then go wide. No long robot will get on that bridge with two other robots and balance.

Three wides will fit with 11inches of overhang. If one of those is long you are never balancing.

What if you want to be one of the picking teams in elims? There might be some other considerations too…

you could have bots one wide then long then another wide and to balance it out you shift the long bot

I vote square bot. My team disagrees but I like it.

Actually, what I really want is a bot that’s tiny but still shoots. That would make me happy on the inside.

Use holonomic or mecanum, you’ll have both.

What if the long-bot turns 90* after it’s on the bridge?

It’ll have to be perfectly balanced, and turning with 2 other robots on the bridge will be hard if not impossible.

The transverse (wide) bot does have its advantages. For one, you have a greater pick up area. Even though you can only carry 3 balls, it’ll still be easier if you don’t have to worry about being perfectly aligned, you can just run over the balls and grab them. Also, there is a greater chance for tipping, but if you keep a LOW center of gravity, you’ll be fine. My team had a transverse bot in 06 and we had no problems, and that was with a giant ramp that you had to climb at the end. It shouldn’t be a problem. But hey, it’s up to team decisions, you should have your chassis fit the rest of your robot’s functionality.

I think you are overestimating how tippy the bridge is. You can be pretty offset and the bridge will still stay “balanced”

Everyone seems to be overestimating this. I predict it will be harder to get two robots on one bridge than it will be to balance the bridge when they are on it.

But the bridges are pretty slanted; that might make it tricky for a ‘wide’ one to climb and climb over them.

Doesn’t this mean that if the outer bots are 4wd, just the slightest error in driving will send one of the robots toppling over the edge?
This 3 robot balancing act seems to be getting harder and harder…

They don’t necessarily have to go single file remember.

Bridge is 48" wide, two relatively thin robots could squeeze next to each other. Or overlap could occur to squeeze a third on.

The offset isn’t the problem; the amount of space available for turning is. With 2 other robots, even if they’re sideways, you’ll only have 20 inches or so in which to turn.

You’ll literally have no space to turn once the other two robots are on. 3 wide robots, with bumpers, will take up 28X3 inches + 4X3 inches, or 96 inches. The bridge is 88 inches. You get a few extra inches if the wheels of the end bots are right at the edge, but not enough. Someone has to hang off or be way smaller than the max dimensions.

Those are some very bold statements. Have you already tested your bridge theory?

Coming from a team that has been Wide Base more often than not, I’ve learned that controlling a wide base robot on a field with terrain without tipping over is a considerable challenge. According to one of our mentors, our Aim High robot was driven very carefully (on a field with no terrain besides the ramp) to avoid tipping. Rapid acceleration and deceleration while driving a wide base robot is a recipe for disaster. Drivers used to a standard drop center 6 wheel drive will find that driving wide base is quite different than what they’re used to. It obviously can be done, but it’s just tougher.

Despite the drawbacks, wide bases do have certain advantages that might be pivotal. The increased area for an accumulator allows drivers a lot more leeway during pickup, regardless of ball control. I can see this reason, coupled with the attractiveness of having a smaller profile on the bridge, driving many teams to build wide base robots; however, I’m expecting that the disparity between Elimination-worthy wide and long bases will favor the latter, due to more teams sticking with what they’re comfortable with.