The rubber pads under the seat of a Cruzbike Quest are attached with glue. As a result, those pads might move and migrate around their mounting point over time or even fall off while riding and get lost. How annoying is that?
In the world of recumbent bikes, it’s not uncommon to discover that a manufacturer isn’t yet producing a replacement part for some tiny item, or their stock pile is small. This might be an example.
So, what do you do if you lose one of those pads and don’t have a back-up yet from Cruzbike? My solution is the following.
I’d create a pad of a thickness equal to the original pad by layering a bicycle inner tube multiple times with Gorilla Glue between each layer (like a wafer cookie). Then I’d cut it to the necessary size and shape with an Xacto knife or box cutter. (Finesse is unnecessary, by the way.) In this case, I would use an inner tube mainly because it would have the right properties (flexible, grippy, cheap) and is the sort of thing a cyclist might have laying around.
If you don’t have an inner tube to sacrifice (or resurrect), I’d look for something with similar properties by browsing the isles of a large hardware store. The main thing, it seems to me, is that you’re looking for a piece of strong rubber that would stay flexible under a wide range of temperatures and will not permanently compress. Neoprene might be a good rubber for this purpose, too, but maybe harder to source.