Can anybody recommend a site that explains how the different driving bits work/function? Best would be with pics.
http://www.drivingessentials.com/Bit%20Overview.php
I like this link. I gives a good general idea on bits 
[QUOTE=DiamondJubilee;8430184]
http://www.drivingessentials.com/Bit%20Overview.php
I like this link. I gives a good general idea on bits :)[/QUOTE]
FWIW, most of the discussion of those bits is not sophisticated with respect to their function.
I have the same question as the OP, so I’d appreciate some of you experts weighing in!
In particular, I have a sensitive little dressage mare who seems to like a custom loose ring mullen mouth bit I have for her. But I want to know if I could get something even more inviting for her by choosing a different shape mouthpiece. I see the most snaffle-meets-mullen mouth bits with loose rings in driving world, so I figured I should come over here to learn.
Thank you!
Oh, and is the purpose of the half-cheek on a mullen mouth to somehow push the “outside” side of the face around when you pull on the opposite side to turn in that direction?
How do you driving types choose the length of those extensions and the size of the rings?
Thanks again.
The purpose of the slots on the lower cheeks of the Liverpool is to give you instant adjustability. These bits are used with a curb strap or chain, so if you can make it very mild - rein on top loop, loose curb chain - but if you find yourself with too much horse, you can get someone to make a change for you without removing the bridle or changing the bit. It’s a safety and convenience thing.
If you are always driving on the ‘dead man’s loop/slot’ then you have other issues. 
They are generally straight mouths because (and don’t get me started on a jointed pelham) if you have a jointed bit, it makes the curb chain much less effective -when the joint bends, the distance between the sides of the bit gets shorter, loosening the chain. Since they are usually straight mouths, you need more options with ports and shapes because you don’t have the various options provided by joints, lozenges etc. There is the straight, the mullen, the glory, and then there are ports.
When you drive you do rely a little more on the bit because it and the whip are the 2 physical connections you have to the horse. No seat, no legs.
I believe the half cheek snaffles that are sometimes seen on ponies or Standardbreds are half-cheeks to prevent the bit being pulled through the mouth, but without the danger of the top cheek snagging should the horse rub on a shaft.
The size of the rings should be proportional to the size of your horse - ponies often just us a 2 slot bit because they are smaller animals. Bigger head, you can use a larger bit.
You will probably get even more/better detail from others but I learned a lot about bits this year.
[QUOTE=mvp;8430738]
Oh, and is the purpose of the half-cheek on a mullen mouth to somehow push the “outside” side of the face around when you pull on the opposite side to turn in that direction?
How do you driving types choose the length of those extensions and the size of the rings?
Thanks again.[/QUOTE]
Actually, the half-cheek is “supposed” to be pointing upward! It was a “safer” version of a full cheek snaffle, nothing to snag on with no lower cheek. But with folks ‘coming to their own conclusions’ when seeing it for the first time, a great many seemed to think it was for preventing bit being pulled into horse mouth. Some forgotten Harness Racing horse used the bit successfully, was greatly copied with his odd bit, until the design turned into the second most common style used with light driving horses, retired Harness Racing horses, for driving with a buggy type vehicle.
In Pony Club, any ring sided bit with a cheek (full or half) is required to have bit keepers attached to the bridle cheekpiece to hold mouthpiece in position across the tongue. Son’s horse was using such a bit, and it was quite interesting how the use of bit keepers changed how bit worked with her, actually she seemed to like it better that way. Bit keepers holding bit up in place, means no ‘delay time’ with bit moving into correct position when reins are activated to slide around on the rings.
If bit is pushing face around, it does not sound like bit is the correct size or reins are being used correctly.
I have SEEN horses gape their mouths open incredibly wide, so even those 6" loose rings on racing snaffles, start going into their mouth. The short sides of a half-cheek or full cheek bit are probably not going to do much good in prevention of bit pulling thru. I also considered how BAD would horse react if he closed his mouth onto the cheek ends pulled into his mouth, so the option of NOT using the bit keepers was removed from my thinking!! Yes unlikely, but possible in a bad situation. Good reason to have a cavesson or full noseband snugged down on your bridles so he can’t open that wide, you hope.
I don’t really know about any sites, but reading about bits I have seen some very good articles in the past in Western Horseman. Principles of leverage, direct pulling, lengths of bit reach to shank, would all apply. Mouthpieces can affect those principles by adding other pressure points to the horse. Bits are bits, whichever discipline the horse is doing. Rein length with Driving might give MUCH more leverage to the hands on the rein, so you need to be a lot more careful with your strength.
I have seen changes in Driving bits over the last years, more choices, more widely available, in correct sizes for both large and mini sized animals. Nice to see that, so animals don’t have to “make do with almost fitting” as in the past with only a few sizes to be found. Measure the animals mouth, before ordering a size. A medium sized horse MAY NOT wear a 5" bit, might even need a full 6" bit for a wide head. He deserves to be comfortable while working, in a bit that fits him well, along with that mouthpiece he likes.
Thank you all, very interesting.
Goodhors, do you have any links to some of the articles you were talking about?
That series of articles is old, didn’t find it with a search for bits. I asked WH for the dates or a link, will have to see what they say back.
They do have a book on Bits, among their other books for sale. I just don’t know that it covers the articles or not. Probably a good book with Greg Darnell being the subject with his knowledge of bits and bitting from his bitmaker side of things. Here is a link to the book, should you want to order for $5. WH does interesting books, usually packed with information, like the Legend series.
