6 Bar or RD4B

My team was wondering which one is better a 6 bar or RD4B. Really don’t know how to make a RD4B so im looking for 6 bar. Which one would be better for the new competition.

So this will depend on your experience in vex and engineering, your resources, and your overall game strategy. My team personally has had a few years in vex and have decent resources. You need to analyze your resources to see your comfortability with building new system. If you don’t feel you have the experience here is a great 6 bar that was my favorite last year.

Ok thanks that helps, but what kind of intake should my team use if im using a 6 bar lift

A couple of choices:

  1. Some sort of grippy thing, operated by a motor or pneumatics
    a. top gripping claw
    b. side gripping claw
  2. side roller
    a. arranged for horizontal intake,
    b. arranged for vertical intake,
  3. A passive intake (will need a release mechanism)
    a. motor release
    b. pneumatic release

1.a and 1.b seem pretty popular.

Beyond this, there are some more exotic intakes.

[edited for clarity.]

That depends on the overall strategy you’re going for. If you want to go for the mobile goals with the same system you use to pick up cones, it could look like this…

If you didn’t want to go for the mobile goals at all it may look like this…

or you could attach a chain bar that swivels like this to your 6 bar…

which would look something like this but with a 6 bar instead of a RD4B

I would analyze your main goals that you want to accomplish this year and design a system that works to accomplish that goal. Feel free to experiment and build upon these design or come up with your own. These are meant to be a starting place for which you can design a personal robot for you. There are also plenty of other example out there I just spent 5 minutes searching for some to show.

Ok thanks everyone who helped me i be building a 6 bar and experiment what intake and get back to you guys

I will look forward to it pm me if you need any help.

Yes sir

Strictly speaking, this is not a 6-bar.
It is a 4-bar stacked on another 4-bar.
But it is a great robot.


It depends on whether you want a linear lift or you think you can do without one.
If it is linear lift, then there are only that few options around - dr4b, elevator lift, scissor lift.

I stand corrected.

Though if i’m not mistaken it has all elements that would make it a 6 bar. They have just doubled the upright bars. Correct me if i’m wrong.

The main difference is that for a 6-bar, it is the same c-channel that runs from the lift tower all the way to the intake.
But if you look at 400x star struck, it is clearly 2 x 4-bar stacked together.

And this means where the lifting force is applied will be different.

I missed that. Thank you.

So in that case which on is better. I have experience working with a six bar lift but I have no clue how to build a RD4B.

400x is not a RD4B there design works the same as a 6 bar but it doesn’t have the same load capacity as an actual 6 bar has. I would suggest building what you’re familiar with. If you’ve worked with a 6 bar before go for it. Don’t allow me to confuse you. I apologize. I wasn’t as familiar with 400x as I thought.

Ok I will build a six bar and keep you guys posted

I have yet to make a value statement on the 6-bar here… RD4B would definitely be better for this competition. 6-bar suffers from less height, and being perfectly linear (if done correctly). That said, if you are not as experienced, a 6-bar is perfectly viable for a more simple robot and would be a valuable learning experience while still being competitive. But, having seen my sister teams have 8-bars at the beginning of the Skyrise season, a non-linear lift is definitely not ideal for stacking high.

Ok then I think I will make RD4B so how do I make one. For gearing should it be 1:7 or 1:5. And where do you mount the gears in the middle of the 2 parelle bars and the two motors.

Now what? I’m getting confused. Who to believe

8 bar vex on google
this (down) is a 6 bar

this is a rd4b