If you have a number of differently proportioned horses a treeless saddle might be the most economical choice for you. Not everyone can afford a different saddle for each of their horses and the treeless can fit your whole  herd!  They can be used on wide or narrow horses and fit well on  horses of average proportions but, DO NOT fit well on very high withered or extremely mutton withered horses. They do fit low withered horses as long as an anti-slip pad is used with them.      

  Treeless saddles are also light weight and easy to lift onto the horse's back and can make saddling easier for people with back, neck or shoulder problems.  Since there is no wood or fibreglass  beneath the leather seat, these saddles are very flexible and form fit to your horse's back and also to your body. There is actually more communication between you and your horse because you can feel the muscles in the horse's back and he (or she) can feel your seatbones push down when you back, stop,or turn your horse.      

  One drawback of the saddle is that they do tend to slip, especially on low withered horses, and a mounting block is recommended when mounting with a treeless. I'm of the school that believes it's kinder to the horse using a mounting block, especially if you are a bigger person and I prefer using one even with a treed saddle. This has not been an issue for me.

   As to the rider's seat size you should definately go to the manufacturer's web site and use their style of measuring your thigh and factoring in your height and weight before deciding on which size seat to order. The treeless saddle will wrap around your proportions and generally if, for example, you ride in a 15" western; you will take a 15 1/2 or 16 inch treeless depending on how heavy you are.    

   I would suggest that you try out the saddle before you make your final decision as to buy or not to buy.  You know the saddle will fit your horse's back as long as he is shaped like the average horse. So, you need to ride one to see if you like the feel of having no tree and to see if you like the way the pommel and cantle are positioned on the saddle.  Many manufactureres have demo models but, you must pay shipping back and to. I have a number of friends with different brands of treeless saddles and they let me try them out on my horse.  I  found I liked the Bob Marshal original but, not the Circle Y Bob Marshall. The pommel position on the Circle Y was not comfortable to me but was just right with the B.M. original. 

One fact about the treeless saddle that I greatly enjoy is that they are QUIET.  There's no leather-rubbing-leather squeak to scare that colt you are starting or to mask the sound of the crickets in the wood or the chicaedas in the trees while out on a pleasant trail ride.

Ebay user aviemarie contacted me about this guide and has one of her own which goes into greater detail about these saddles.

    So, be quite sure that that new or used treeless will be a good fit for your horse and yourself by following these guidelines.     Anne