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Traditional single-belt lane balancers may fill the output side equally but don't draw exactly the same amount from the I put side.

Googling for "input balanced" single belt balancer designs did not yield any designs that achieve what I described. (Plus, since these could be needed on every belt that leaves the bus they'd need to be reasonably compact)..

Has anybody seen such a design? Is it even feasible without combinators?

The input and output balanced lane balancer on the wiki which you surely found on your search does exactly what you want:

Bilka wrote:The input and output balanced lane balancer on the wiki which you surely found on your search does exactly what you want:

I use it both on exit from the smelters and on each line that branches off the bus, and it isbetter than nothing, but under some conditions the bus still gets unbalanced.

Edit:. Never mind, the image did not load until after hitting Submit. That balancer looks different than the ones I tried. Thanks, will give it a shot.

All lane balancers operate on the same simple principles:

1. Split the input belt into seperate lanes
2. Construct a full belt from each lane
3. Merge the resulting lanes back into a single belt.

The above example is ofc made larger to see the steps easily. There's many tricks that can be used to make compact lane-balancing balancers even for multiple input lanes. The correct search term is thus "lane balance/ed/ing/...".

Bilka wrote:The input and output balanced lane balancer on the wiki which you surely found on your search does exactly what you want:

This looks to waste an underground belt. Specifically the left pair could be reduced to just one underground I think. Take the bottom left underground and the curved belt feeding it. Turn the underground 90° clockwise and put it directly after the splitter. Change it's direction to output. Add a curved belt after it to feed the second splitter.

I suspect the reason for the current design is so they can be built side by side without undergrounds interfering with each other.

cbhj1 wrote:I suspect the reason for the current design is so they can be built side by side without undergrounds interfering with each other.

Would still work. Just don't put a mirror image of one next to it. It will connect with an underground going the other way.

Why do you all make it so complicated ?

I just use a splitter and merge the two ways into a single belt....
There is no ned for the subway-belts

nosports wrote:Why do you all make it so complicated ?

I just use a splitter and merge the two ways into a single belt....
There is no ned for the subway-belts

That is the one I was using and didn't quite do the trick: split then merge on both sides of a belt.

That design:

- Correctly causes a full output belt.
- But under some conditions it causes one of the lanes of the input belt to be drained faster than the other. I am not sure why, but I suspect that it simply reflects the consumption.

So, I *suspect* (not know) that it is viable as an input balancer when you are drawing a half belt but not viable when you use full belts but inserters are taking items mostly from one side of the belt.

I i have a given input and thous it will be symetrically placed on the single belt.

IF the drain is unsymetrically and the input can't cope with the drain there is in my opinion no way you can solve this....

if the input can cope with the drain, but a side of the belt is chocked then with the single spliter all will be sorted of the lacking side of the belt - thouse improving the throughput.

For me its easier to input just more of some to have a full output belt, because if you think of it, then it need to be full to take full advantage of a filled belt

IF you have two input belt with differnt fill just take advantage of the input/output options of the splitter, so you can choose a main feed which will be filled by the secondary feed


I suspect all will do the same, but i would not think to much of it, because either the belt needs to be full --> more input, or it is even as possible, when the output cant cope with the input symetrically, or when the drain is highly unsymetricalla, one side will chocke and the reamaing input will be sorted to the lacking side ......

nosports wrote:I i have a given input and thous it will be symetrically placed on the single belt.

IF the drain is unsymetrically and the input can't cope with the drain there is in my opinion no way you can solve this....

if the input can cope with the drain, but a side of the belt is chocked then with the single spliter all will be sorted of the lacking side of the belt - thouse improving the throughput.

For me its easier to input just more of some to have a full output belt, because if you think of it, then it need to be full to take full advantage of a filled belt

IF you have two input belt with differnt fill just take advantage of the input/output options of the splitter, so you can choose a main feed which will be filled by the secondary feed


I suspect all will do the same, but i would not think to much of it, because either the belt needs to be full --> more input, or it is even as possible, when the output cant cope with the input symetrically, or when the drain is highly unsymetricalla, one side will chocke and the reamaing input will be sorted to the lacking side ......

You are balancing / filling the output. But the question was about balancing the input side. Completely different issue.

mrvn wrote:

Bilka wrote:The input and output balanced lane balancer on the wiki which you surely found on your search does exactly what you want:

This looks to waste an underground belt. Specifically the left pair could be reduced to just one underground I think. Take the bottom left underground and the curved belt feeding it. Turn the underground 90° clockwise and put it directly after the splitter. Change it's direction to output. Add a curved belt after it to feed the second splitter.

Unfortunately, that won't work, because the splitter would then be sideloading onto the left side of the belt instead of the right side. Which means the second splitter in the balancer won't work correctly.

tzwaan wrote:

mrvn wrote:

Bilka wrote:The input and output balanced lane balancer on the wiki which you surely found on your search does exactly what you want:

This looks to waste an underground belt. Specifically the left pair could be reduced to just one underground I think. Take the bottom left underground and the curved belt feeding it. Turn the underground 90° clockwise and put it directly after the splitter. Change it's direction to output. Add a curved belt after it to feed the second splitter.

Unfortunately, that won't work, because the splitter would then be sideloading onto the left side of the belt instead of the right side. Which means the second splitter in the balancer won't work correctly.

Right, you then need an extra belt so the underground belt side loads onto the belt going north and items end up on the right side of the belt again.

Here's one that may be what you are looking for:

@Trebor It took me a while to understand how this balances the two sides of the lane, but now my mind is blown.

This is amazing! I will definitely use this one.

I'm not sure if you realized, but your design is a full-speed dual lane input balancer. It isn't limited to a single belt.

The only drawback ... it's not a perfect output balancer :/ it only fully balances the input.

Here I created another version that fully balances both input and output of a dual belt at full speed.
I don't think it will get a lot more compact than this.


The important principle behind it, as can be seen in Trebor's post, is that the final splitter merges two lanes that have their sub-lanes swapped.
As can be seen in the next image, the copper and iron get swapped, and the last splitter then merges those two swapped lanes.
Swapping the left side twice (opposed to not at all, as in the previous version) is necessary to create an even output balance.

Here's a slim version, which is probably useful for integration into large busses:

Unless you are merging belts, blocking belt lanes or using a belt that transitions from a faster belt to a slower belt, 90% of the time you don't need to lane balance belts.

Also you are lane balancing the left belt twice, which is redundant.

Zavian wrote: ↑Wed Oct 07, 2020 1:11 pm Unless you are merging belts, blocking belt lanes or using a belt that transitions from a faster belt to a slower belt, 90% of the time you don't need to lane balance belts.

Also you are lane balancing the left belt twice, which is redundant.

You are of course correct. My main usecase for input lane balancers is at the transition from the smelteries to the main bus, or at train unloading stations.

The double balancing on the left side is on purpose, it's not actually a balancing, it's a sub-belt swap. The two sides of the left belt get swapped twice. If you only care about input balancing, the entire left side is redundand, as can be seen in the previous post. But to achieve output balancing, you need the double-swap.
If you'd only have a single balancer on the left side, both output lanes would be the same and the final, actual balancing splitter at the end would do nothing.

Here, this shows what happens without the second sub-lane swap. Only input lanes 1 and 3 get pulled:

This is the only belt design I know which truly guarantees input and output balancing.

"Waste of resources" or not, for balancing 1-1 belts I would just use the 2-Belt I/O Balancer, because it doesn't use unconnected underground belts, which saves you from unwanted underground belt connection mistakes in very tight spaguetti places.

2-Belt I/O Balancer

4-Belt I/O Balancer