Most good whips or at least most good bullwhips have what is called a "double plaited belly". This consists of a rolled or plaited leather core attached to a rod that makes the foundation of the handle. Then a layer is plaited over both the handle and the core. To smooth out the layer and add density a bolster is precisely fitted around the plaited layer. On good quality whips this bolster is usually a very thin piece of leather. On cheap whips it's paper, duct tape or masking tape. The next step is to plait another layer over the bolster. Typically this layer is a higher plait number to accommodate the increase in diameter. Then another leather bolster is added. At that point the whip is ready for the overlay. Of course this is what is inside a good quality whip. In a lesser quality whip like the kind you can find sold in most tack shops these days the inside of a whip can and usually does have less layers and is some cases there is just a bunch of rope or if your lucky leather strips. There is no plaiting at all. I have even seen paper used for the entire insides of a whip. But that was a very cheap whip. The way I see it there are two reason the insides of a bullwhip are made this way. First, all these layers of leather help to build the whip up to a diameter that is large enough to match a comfortable size handle.

I have noticed a trend in some whip makers to make the handles of their bullwhips very narrow. I my self have been guilty of this in the past. In some bullwhips that are made for very fast sport cracking this can be a plus. But you do sacrifice density and density in the thong is what makes a bullwhip crack with out effort. This is according to good ole Newton. Second, a bullwhip has one weak spot and that is the junction between the handle and the thong. This is where the whip gets the most stress. The extra layers help maintain the wear ability of that junction. I have also noticed bullwhips that are made with a double plaited belles tend to roll out much smoother than those that don't.