While watching a snow biking video, I saw that some of the bikes use a true swingarm design, which matches most motorcycles (as does much of bicycle technology). While this looks rather interesting, I'm wondering why it's so uncommon (and much more common are multi-linkage, seemingly more complex designs)?
I've found the bicycle he was riding, a Chumba F5, shown here:
If I had to guess, I'd say it was solely weight concerns to not use this design with less moving parts. It also (seems to) allow for more travel, so is there perhaps an upper limit on how much travel you can get with the multi-linkage design?
Further, I've seen the Y-Frames (especially on BSOs) criticized for having poor flex characteristics. Does it again just come back to the weight issue in that more reinforcement is required for these designs?