This is a general help, intended for all different varieties of horse bit. A general guide to ensuring your horse’s bit is at the correct height in the mouth would be to aim for ½ – 1 lip wrinkles at the corners of the mouth. Please bear in mind when fitting the bit that mouth conformation varies and some horses are much shorter from the corner of the lip to the muzzle (‘short smile’). In this case it is often tempting to shorten the cheek pieces excessively thus causing the horse much discomfort and to appear to grin like a Cheshire cat.
When fitting a bit with a fixed cheek, such as the Eggbutt Snaffle Bit, the lip should gently brush up against the butt end ensuring a snug, although not tight, fit.
If using a Loose Ring then the general rule would be to have clearance either side of no more than one eighth of an inch from the corner of the lip up to the hole that the ring passes through.
The fit of the bit needs to be assessed at rest and then with a contact. It is quite common for horse riders to employ loose rings that are too big for the mouth and then run the risk of rubs in the corner of the horse’s mouth.