DR4B width?

For an internally stacking DR4B, generally how wide are these in holes?

As wide as possible. A lot of teams have their towers for their dr4b on the farthest possible hole out (basically their towers sit on top of the c channel of their drivetrain), and some others, usually ones that only have one tower on each side, have their towers bolted into the sides of their drivetrain, which requires them to basically sit one hole inside. This leaves as much room as humanly possible for a secondary arm and cone intake.

Even if you don’t have a set amount, I would highly suggest just making it as wide as possible and working from there. For externally-stacking robots, you don’t necessarily want (or need) that wideness, but any internal stacker would greatly appreciate it.

On a 35 wide c-channel, I have mine 3 holes away from each end.

Our bot actually has them as far in as we can get it. Then we just build out instead of build in for our secondary arm. Its working well for us so far

Is there any particular reason your team chose to do this? Right now I’m just imagining a rather unstable dr4b if the towers are as far in as possible.

It’s actually extremely stable. We did it so that we could get extra height by building between the wheel base. The towers are about 5 inches apart and it works great.

People are making internals much wider and bulkier than they have to be, why make a 35 wide drive base when you can make a 30 wide drive base. And then why make an 30 wide drive base when you can make it 25 wide ;).

It is very much possible to make a rd4b stable without increasing it’s width.

hmm, antichamber strongly advised against a 25 wide chassis in this vid https://www.youtube.com/watch?v=FzKPYCJnxnk

Ours is as wide as possible on a 17.5" chassis (35 wide I think, idk I’m not a builder) and it’s pretty unstable. With enough rubber bands and crossbracing it works and doesn’t tilt much, but it is not ideal. I would recommend going much thinner. Wider structures won’t tip sideways as easily, but because of the distance between the sides, there will be much more force on cross-bracing (think of it as a lever; a larger lever arm means more torque). A thinner one will be more prone to tipping but will have much less slop and lean. In general, as long as your chassis is still ~18" wide, a thinner DR4B (within reasonable limits) will probably be more stable than a wider one.

Please please please don’t make a 25 wide robot. Turning gets super sketchy and it’s not worth it. The only benefit I see for a smaller base is that you don’t have to ram into cones in auton to get the mogo, but in the end, a 30 wide does that fine and a 35 wide chassis, while ramming into the cones, still works fine.

oh yeah forgot about our Lord, our saviour antichamber. Ofc only his point of view matters and none others.

honestly tho, no need for such salty aggression. In general, antichamber knows what he is doing and his points about the using a 25 wide seem valid. I brought up this video because it had popped up in my recommended and I watched it before coming here. You could use actual facts and experiences to explain why you believe a 25-wide chassis is better. I remember in the beginning of the year, many people optimized for this as in auton you could fit right through the cones but obviously looking at all the good bots now, everyone is wider than 25 holes

It didn’t work for his specific design. He said don’t do 25 wide if you are copying his robot.

ah true. im not sure if he meant an internal stacker in general or one that utilized his plexiglass (i know its not) stacker

Uhh, please don’t make a 25-wide robot. I’ve already commented on this, but please don’t do this. It’s not worth it. Benefits do not outweigh the costs