Standoff lift or c-channel?

I’m rebuilding my rd4b and wondering if using standoffs for the arms would reduce weight by a decent amount?
I want to use a 2 motor rd4b using highspeed motors with either a 1-5 or 1-7 ratio.

It would reduce the weight, but at what price? You would lose a ton of stability/strength if you did so. I would advise against it

What if i did a hybrid and used one standoff arm with one c-channel arm to provide enough structure. Also if i were to add flatbar to brace the design?

Hey Gameon! Standoffs are pretty close to the weight of a 2 wide c channel, so you’re not really accomplishing anything by doing that. However, if you’re really interested in lightening your lift, you could try cutting a 1x2x1 c channel in half to form a 1x1 L. These pieces are half the weight and probably 80% of the strength of a normal c channel. You might only want to use them on the top stage of the lift, however, because they’re quite a lot harder to attach things too, and they flex a bit more easily than a normal c channel. If you do this, your lift will be significantly lighter.

In any case, 2 motors on 1:5 speed will be a gamble. The lighter your lift, the lower friction your joints, and the more linear your bands, the better off you will be. But, with enough tuning, it’s totally possible to get that sort of gear ratio working.

Good luck!

Thanks for the info @Anomaly another question i don’t use plexi very often but would using that for my arms be a way or reducing weight without giving up too much structure?

you could try shorting the 2x35 bars themselves but your lift would be smaller in height

No :stuck_out_tongue:

Lexan is extremely light relative to c channels, but you’re sacrificing a lot of strength. It might be worth attempting, but I’d be extremely surprised if it held up.

However, if you do try to do it, you’ll need to bend the lexan in an L shape and possibly double it up. That way, there’s more strength in all directions, and the lexan is less likely to flex.

Standoffs are just over half the weight of a 2 wide c channel, but it depends on which length standoffs you use and how many couplers.

Not if you know what your doing.

@Bryan R I was thinking of using 6inch standoffs mostly to cover the distance and having a few cross bars to secure it better.

Standoffs longer than 1.5 inches are heavier per linear inch to increase their strength over long spans, so the lightest and longest standoffs are 1.5 inches. You can connect standoffs using couplers, but they are steel, which makes the bar even heavier. If you want a really light standoff bar, use 1.5 inch standoffs or 1 inch standoffs and buy nylon couplers. Of course, that would also make it really weak, so I would recommend using 1x1 L channel like @Anomaly suggested, or use aluminum chassis rail, which is 75% of the weight of c channel.