I have been thinking about writing down the tricks of loading and carrying different cargo with bicycles. Partially because it is quite different than carrying load in a car, and also because with a little preparation and technique the carrying capacity can be extended and the carrying experience greatly enhanced.

• Secure everything to the body of the bike. Moving content may affect your balance, and windswept content not only may get damaged, but can distract you riding in traffic.
• Balance the load. Being balanced is especially important when the ride is hilly, the road is uneven, or you are close to the carrying capacity of the frame (or the carried weight is close to theat of your own). In each of these cases the lack of balance will show up as volatile bike handling or frame torque, that is disconcerting, and a sideway pull, especially while using the brakes.
• Load placement is important from the visual perspective as well. Mark oversize items with a red flag where it sticks out the most, and place the bulkier part on the traffic-side of the bike, so you don’t hit the curb, and are more visible to drivers. They will also give you more space this way!



• If you carry people be careful about load limits. Some cargo bikes have a fairly low limit of weight carrying capacity. For example attaching the XtraCycle FreeRadical kit to a regular bike frame logically makes the combination weaker and more prone to torsion: It reuses the same wheels, and ads an extra piece between the regular frame and the rear wheel, while also elongating the wheelbase. None of these will make the resulting cargo bike any stronger, exactly the opposite. But why is this about people especially? Normally, when I load my bike with dead weight, I am aware how much I load. But when I give a ride to another person, the act of sitting onto the bike is so much easier than loading the bike with the same dead weight. So don’t overburden the bike. See some approximate load carrying limit below.
• It may not be windy when you are loading the bike up, but it will definitely blow more when you are riding. So ensure the lighter and larger objects are securely fastened. And if you carry a sail, be aware of the wind;-)
• Mind your own power too: Depending on your stamina and the length and steepness of the hill you plan to climb, the resulting limit may be quite low. You can in fact calculate it a good calculator is here.



• The lower the center of the weight is, the easier to handle a bike. This doesn’t necessarily true for trikes and trailers, but the lower the center of gravity is, the better in general.

Bike/trike carrying capacity by type (combined contains rider weight, otherwise the limit is without rider):

Bakfiets style bikes: 200 lbs
Christiania style cargo trikes: up to 800 lbs depending on the kind!!!
Bikes at work Trailers: 350+ lbs
Sun Atlas Cargo: 400 lbs combined
Surly Big Dummy: 220 lbs + rider
Surly Long Haul Trucker: 300 lbs combined
Xtracycle FreeRadical: 100 lbs + rider
Yuba Mundo: 450 lbs + rider!!!

References:
Longtail cargo bikes
Joe cargo bikes