Live weight versus dead weight
It is important to remember that live weight (i.e. a rider) rides differently than dead weight (i.e. a pack load of any kind) and the 20% of body weight rule doesn't necessarily apply to live weight. A rider can move and shift in the saddle to compensate for rough terrain and can get off and walk. A good rider is also easier for a horse to carry than an inexperienced one. An experienced rider in a good fitting saddle on a fit horse could be fine on a long, tough ride, even if the combined weight of saddle and rider is more than 20% of the animal's body weight.
Packing the load
Dead weight, on the other hand, does not have the ability to adjust to terrain changes and, therefore, must be carefully packed to stay put and be comfortable for the animal to carry regardless of conditions. Remember, gravity works. Once dead weight begins to slide off to one side, it has the tendency to keep going. This can upset your animal, cause soring or, even worse, cause a wreck.
Unfortunately, there are no hard and fast rules on how to pack a load. It depends upon what you are packing, your equipment, your animal and all of the other conditions listed in Part I. However, there is one rule to always bear in mind: equal size, equal weight and equal weight distribution. If you follow this rule, you should generally have less trouble packing a load.
- Equal size. It is easier to balance a load that is the same size on each side. This is easy with panniers and saddlebags, which have a fixed size. It is more difficult with mantied loads. This is one reason I recommend panniers to beginning packers.
- Equal weight. Any kind of load should be balanced from one side to the other. This means that if your panniers, saddlebags or hornbags do not weigh the same, you need to balance the lighter side by hanging something else off of that side such as your rifle scabbard, pack saw, camp axe or another such item.
- Equal weight distribution. Try to pack each pannier, saddlebag or hornbag so that the weight is distributed evenly throughout. Do not pack all of the grain in the front of one pannier and your down sleeping bag in the back.
Both pack saddles and riding saddles need to fit well to be effective and not cause additional problems. A poorly fitting saddle will not properly distribute weight across the horse's back. If the fit is particularly bad, it can cause sore muscles or even open wounds. Before loading any weight on your animal, be sure to double check the fit and condition of your saddle. (Also be sure to use a good saddle or pack pad and check to ensure that it is clean on the side next to the animal. Grass seeds, burrs, crusty spots of dirty sweat can all cause a sore to develop on your animal).
When loading saddlebags, the weight and ability of the rider should be factored with the horse's size and condition as well as with the fit of the saddle. An inexperienced rider can unknowingly throw the horse off balance and too much extra weight in the saddlebags (especially if badly packed) will make recovery more difficult. Additionally, poorly designed saddlebags can hang too low or constantly shift, which can irritate your horse and put extra strain on him.
No simple answer
There is never a black and white answer to the question "How much weight can my horse carry?" The answer always has to be determined on an individual basis considering the factors listed in Part I. You know, most of these items are simple common sense, but so many of the "horror" stories that I have been told over the years could have easily been prevented if the people involved had just critically and honestly judged their animals against this list. So remember, if you have any doubts at all about your horse's ability to do whatever task you want to ask of him, make adjustments, live without some things or just don't do it.