How to Stop Bucking in Horses

about fitting your horses saddle as you would buying yourself new shoes. Saddles arent onesizefitsall. Ideally you should buy a saddle after you buy the horse. Enlist the help of a good saddle fitter and dont depend on saddle pads to fix a poorly fitting saddle.
Your horse could be objecting to having the saddle girth over tightened. You should be able to slide your hand between the cinch or girth and the horses body. Over tightening can cause pinching and chaffing both in the saddle and cinch areas.
Bits occasionally can cause problems especially if the horse has a dental problem.

Be sure your horse has a bit that fits is comfortable for him to hold and is the mildest possible to control him.
How Are You Riding Your Horse?
It may surprise many people to know that horses dont actually like being ridden or driven. Much of horsemanship is convincing your horse to do things willingly that it sees no earthly reason to do. Some horses figure out very quickly just how skilled and determined the rider upon its back is. Just like people they can become very adept at avoiding work they dont like. If your cues are muddled you arent able to read the horses thoughts and dont know how to curb unwanted behavior many horses will pick this up.
When a horse bucks it probably gives some signals beforehand. It is up to you to learn how to recognize these signals and take countermeasures before the bucking actually begins. This is where a good instructor can help you hone your skills. Many people spend many hours and dollars on finding quick fixes e g. buying more severe bits tiedowns etc.. However the answer to most behavioral problems under saddle is to increase the skill and knowledge of the rider.