ridecamp@endurance.net: [endurance] Rider Weight

[endurance] Rider Weight

Fend, Gary (gf@merkle.baaqmd.gov)
Wed, 27 Mar 96 10:38:43 pst


The posts on rider weight seem to be talking about two different
things. One is whether or not the same horse is better off carrying
less weight. The other is whether or not a large rider needs a large
horse.

The first is obvious. Would you rather go backpacking with 25 lb pack
or a 75 lb pack?

The second is not so clear cut and the following is a theory from high
school physics that was discussed by Dr Bennett at the AERC convention
a few years ago.

Assume you start with a horse that is 14-3 and weighs 800 lb. (Any
assumed dimensions and weight will work). Since the weight will
increase by a factor of the linear dimensions cubed, a 15-3 horse
will weigh in at 976 lb. (800*15.75^3/14.75^3)

Now assume the smaller horse has 100 theoretical "strength units",
again any number will do. Since strength is a factor of the linear
dimensions squared, the larger horse would have:
100*15.75^2/14.75^2, or 114 strength units.

If you put a heavyweight, say 220 lb, rider on both horses, the
smaller horse would be carrying 1020 lb and the larger horse would be
carrying 1196 lb. (His own weight plus the rider's weight)

14-3 horse: 1020 lb/100 su's = 10.2 lb per strength unit

15-3 horse: 1196 lb/114 su's = 10.5 lb per strength unit

The larger horse is carrying more weight per unit of strength!

I try to explain this to my mare every time she suggests I get a
bigger horse. She doesn't believe me either ;).