You have great angle differences in using a breastcollar or a full neck collar with hames. Draft horses use full collars most times because they have more surface to “push” against, moving big or heavy loads, than a breastcollar gives them. Driving horses are actually pushing into harness to go forward, not technically ‘pulling’ their loads. Drafts are often sold with their well fitting collar, so new owner doesn’t have to figure what will work well on that horse. Hames fitted on full collars need their trace setting to be placed over shoulder correctly, to get the best angle of draft, to use the horse power most efficiently moving the load. Collar does not rock with traces properly placed.
Michigan State University did many studies years ago to learn those best effective angles, for plowing, dragging logs, pulling farm wagons. Sometimes lengthening traces would get you the needed angles. I am sure the Equine Department there would share the information with you. It may be online too, if you do a search.
Breastcollars should not have such acute trace angles down to their singletrees. You want it down slightly, not straight back or uphill, that is incorrect, even on very light carts. Horse has less surface than full neck collar to push against. We moved a singletree on our Road Cart to below the crossbar, to get that slight downhill angle. It was recommended by two very well known horsemen at a clinic. I felt pretty good that this was their only critism of my turnout! They had plenty to say to other folks!! Whew!
There are other factors that can come into play, width of breastcollars, straight or V cut, padded or single thickness, style of shoulder straps. English or UK carts often have chains from singletree to axles, aiding horse to “pull low” yet not affect his line of draft on traces. This is called axle draft. Many of those 2 wheel carts are quite heavily built, along with seating for 4 people. They may have adjustable seating for balance or maybe not.
Size of the equine affects how you set them up to work. So many modern Draft Horses are HUGE! Not going to succeed well as farm workers on such long legs. An inefficient design for that job. Showy in hitch classes though, which is a big market for young horses. My Grampa seldom owned anything much over 16h. Said they ate more than the work you got out of them. Had to get more hay and grain to work well, than smaller horses he could grain lightly and graze on pasture free. Then there was the extra work heaving harness way up on them daily, unharnessing. He bought the taller ones for resale after he got them going well. They sold easily then and made him a profit.
One thing to mention, was a past fad for light marathon vehicles a while back. Trying to reduce the load for better recoveries. We saw MANY bad combinations, horses hooked to pony carriages, hooked too close to vehicle with short shafts or poles, kicking the vehicle when extended or carriages hitting horse hind legs, traces hooked below hock level, lifting front wheels almost every stride!! Force of large horse breaking welds, front ends while going forward. Folks totally ignoring all the older horse, angle, weight of vehicle, rules of hitching. We seem to have gotten over that now, but always is someone who thinks to “reinvent the wheel” to gain competition advantages.
