Bit Measurements

For various reasons I did not get to ride this past week.

To drown my sorrows I got on-line in search of yet more titanium double bridle bits. During my search I ran into something really interesting, a company that sold its titanium bits measured in inches, not millimeters (mm). I FINALLY got to buy some widths of Weymouths and bradoons that Fager Bits do not produce, except by special order, 4 3/4” and 5 1/2”, as well as a set that measures a true 5 3/4” (I found those bits on Ebay, and they are also available from the Horse Bits Ireland web site, where they sell the Stiel brand titanium bits).

Then for some odd reason I got the idea to see if there were any 6” titanium Weymouth curbs available. There are none available except for a few in stainless steel. During my search I landed on the Neue Schule website (they have no titanium bits) and when I checked on their curb bit sizes I ran into millimeters, yes, but they were of different widths than most of the bits available in millimeters. I got out my old index card where I had listed the different measurements from 4 inches up to 6 inches and their conversion to millimeters and I realized that the Neue Schule people's millimeter measurements were the nearest thing possible to measurements in inches, down to just rounding errors.

So I will now list the equivalents.

Millimeters-(Inches) Inches Inch to millimeter equivalents

105 mm (4.13”) 4” 101.6 mm

110 mm (4.33”) 4.25” 107.95 mm

115 mm (4.53”) 4.5” 114.3 mm

120 mm (4.72”) 4.75” 120.65 mm

125 mm (4.92”) 5” 127 mm

130 mm (5.118”) 5.125” 130.175 mm

135 mm (5.3125”) 5.25” 133.35 mm

140 mm (5.5156”) 5.5” 139.7 mm

145 mm (5.7”) 5.75” 146.05 mm

150 mm (5.91”) 6” 152.4 mm

So I found that the Neue Schule and the Horse Bits Ireland Stiel bits are sold in measurements that closely follow the English inches that we use here in the USA. The Fager bits are sold in millimeters that roughly approximate English inches.

Why does this matter at all? Well some horses get incredibly fussy if their bit is a little bit too small. Generally I find that the horses are more forgiving about a bit being a little bit too big, but a too big bit can slide around in the horse's mouth and cause some horses distress if the rider's hands are not completely steady and even (like mine are at times).

As for the stainless steel bits, I have found bits from 3.5” up to 7”. To get the equivalents on these sizes the formulas are: mm to inches--multiply the mm's by .03937 to get the inch equivalents.

inches to mm's—multiply the inches by 25.4 to get the mm equivalents.

Just one more note. IF you have wrinkles at the corner of the horse's mouth you probably need a slightly wider bit. One wrinkle is not a big difference, but two or three wrinkles put the bit up where the horse's skull gets wider. This can happen if you add a flash strap, use a dropped noseband, a Micklem bridle, or you just want the bit higher (sometimes it is the horse who wants it higher.) Two wrinkles or more—be prepared to buy your horse a wider bit if you want to keep your horse happy and taking contact confidently.

It can really pay off to get your horse a bit that is made of a metal that does not cause an allergic reaction and which fits well. The allergy problem is why I changed from stainless steel to titanium, and now I can find bits in a wider variety of widths than I had access to before.

Have a great ride!

Jackie Cochran