Over time, the effect is to wear down the heel and extend the toe, which hurts the horse's motion, and to unbalance the hoof. When a horse's hoof is unbalanced and improperly shod, it will hurt the horse's locomotion and damage the hoof. For racing thoroughbreds, most shoes range between size 5 and 8. Sizes are determined by the total length of the metal in the shoe. For one popular manufacturer that ranges, in a front shoe, from 12.5 inches for a size 5 to 14.25 for a size 8.
Most racehorses now wear aluminum shoes where once they raced in steel.
The turndown gets the horse's heel off the ground so the soft tissue is not being constantly beaten. They are cleats of metal that go straight down from the shoe, usually toward the heel, into the track. The idea is to anchor the foot on the slippery track. Some trainers use them in any conditions. Like jar calks, stickers extend from the bottom of the shoe to give more traction but are not as large.