Factorio Forums

Here is popular belt rebalancer:

But, as you can see, output of this rebalancer is sparser than input.
So, here is proper rebalancer, that can keep density of items on the belt in case of full load:

...or you just use faster corner belts and one faster belt at the merging point. (express in that case)

But there is quite a lot of time, when you use red belts, and express belts are not yet available.
Also, I'm not 100% sure, but I think first version even with express belt in the middle wont give maximum density.
You probably need more then one, to "compress" output.

If I'm balancing a belt there is additional space on the input so there is no need to worry about compression

https://forums.factorio.com/forum/vie ... 808#p12891

This design will rebalance quite good and guarantees a better compression as the standard rebalancer with one splitter (but perhaps not so good as above). And it splits not 1:1 but 3:5!