DarrenM wrote:...What kind of harness did you use Terra?
The first trailer I used a shoulder and hip harness with chest clip but I soon dismantled it into just a hip harness and then threw it away within 500kms. Too much vibration travelled through the cart, handles and harness. It was easier just pulling without a harness, my wrists and elbows could buffer the vibrations. I designed the handles long and balanced comfortably at hip level with room for a long stride.
If you do design a pull cart consider that it will always be easier braking the weight if it is in front of you. You could fit a braking system but that too will be easier to operate if the cart is in front.
If you buy a bicycle trailer and fit handles or a brace system/harness think about the wheel design. Can you fit larger wheels to the design or do the wheels fit within a fixed frame? You might appreciate the flexibility to try different sizes. Burley Cargo was a great little light weight trailer except I often wished for larger wheels which the frame didn't allow for, they have since removed that outer frame. The Burley Commute looks like what you're after. Simple, light, good for short walks and can be pulled or pushed, it may get jagged on rocks and tree roots but can be hefted/bounced over easily enough or just fit bigger wheels. Great for lighter loads of less than 20kgs. My current barrow is designed for up to 100kgs (lots of water) but unloaded i can lift it with one hand. So far so good and the average weight has been about 55kgs, max 70kgs. The wheels are in the middle of the load, packed well, balanced, it can be pushed with 1 finger over flat terrain. Not so fun on any degree of incline or decline but that weight wouldn't be fun in any kind of cart design unless fitted with a motor or brakes.