Originally Posted by Summer08
If you've got a big horse an its used to the collar and traces' weight, you are not going to break anything using a work setup on a light load. Whereas if you use the breast collar set up and misjudge your laod you can break equipment and strain the horse. There is a big difference on where the pull is on the Horses frame in the different designs, so take breed into account as well.
Well put and welcome to the foum.
So ... you can use a rule of thumb by saying that you can never go wrong using a hame but you can, if the load is too heavy, by using a breast collar.