Recumbent, diamond-frame or trailer to move heavy things? Heavy things can be a lot of books, full beer cans, construction woods and other misc in a place where I cannot use a car and the trip is long and suitable for riding. So which one would you favor? And which kind of adjustment would you make to move heavy things? I have seen a post office with diamond-frame bike framed with a metallic balancing thing, for example. Any such devices for other options and what are they called? Stabilizer? Support device?



I have long been looking for something like that but haven't yet found from second-hand market, I believe they could be reasonable priced. A more sturdy example here from Austria with side wheels, now the frame is original. I don't know yet how much such side supports can stand so open to any suggestions, does not need to be diamond-framed like in the picture.
I would go with a four-wheel recumbent for carrying a big load any distance, just because it's comfortable and controllable. I have one, after building and trying a wide variety of load carrying bikes. It will carry 120kg in a 60x80x50cm bin (220l), and with a bit of plywood instead has carried a chest freezer and a washing machine (separately). With a trailer that has a similar bin I can carry 250kg of soil or other bulk material. It has a Rohloff hub and disk brakes on all four wheels, which makes 250kg loads relatively controllable.

The classic "long john" bike is a good compromise - they can carry 60-80kg bulk loads quite easily and are as fast and nearly as maneuverable as a similar weight diamond frame bike. But, of course, the load is in one piece, low down in front of you. Especially when carrying kids, the advantage of being able to see your load is significant. A long john can often also take a rear rack for added capacity (but you're back to breaking the load up and putting it in panniers).

If you can split the load, a Surly Big Dummy (or XtraCycle) works well, they're easier to ride than a long john but the split load makes them less flexible.

For short trips an upright trike based on a rickshaw works well, but riding slightly canted over (from road camber) is a very odd sensation that takes a bit of getting used to. I've seen one of those with a wheelchair strapped to the platform which was quite cool.

Trailers work well for loads up to about 100kg, but more than that is getting quite dangerous - if your bike falls over the trailer will not stop, it will run you over. For long loads a "jinker trailer" where you attach the load to your bike then the trailer to the back of the load can work really well. I've carried 6m lengths of bamboo and timber behind an upright bike this way. A cheap trailer is often a good start but they are usually poorly made and fall apart if used regularly. Expect to spend $500 or more for a trailer that will carry its rated load 5Mm or more.

My "big trailer" is 1m wide by 2.4m long with four wheels and inertia braks on the front wheels. It's only safe to tow behind the quad but will take ~500kg. It's more a question of how much I can pull.