I’ve got a question about Hunter style frames (two sets of narrow legs on each side, as opposedto one thick leg on each side). For anyone with experience on these, is there any problem with strength? How about frame flex? It seems like because of the narrowness of the legs, they would flex from side to side while riding, or when jumping. Would they work for trials? Freestyle? I notice that they are usually used for MUni. Would they be appropriate for anything else?
Seems pretty solid to me, and that’s on a Coker. I noticed a lot more flex on the standard frame. So I would imagine the shorter the frame the less flex. I don’t think the crown is suitable for Freestyle.
So the Hunter style is good for road riding and I’m assuming MUni. Anyone from the trials scene have an opinion?
By the way, I’m also including this unicycle when I mean Hunter style.
The Hunter is proven bombproof for muni and distance. Strength and flex totally not an issue. Not good for freestyle due to sloped crown. Not sure I’d worry about it for trials, since there are so many well-established alternatives. Since trials often combines with street, I think a flat crown would be more than a “nice to have”.
The Hunter design is solid.
Making a solid unicycle with that style of frame is a combination of geometry and solid tubing with a large enough diameter.
The geometry is how much of a triangle the two legs form. The Hunter design uses a good sized triangle. The DM Vortex frame, unfortunately, did not. The Hunter design is stiffer and less flexy than the DM Vortex design. Design the frame so the geometry makes the frame stiffer.
Don’t skimp on the tubing. Use a large enough diameter that the tubing is stiff enough. The Hunter uses standard bicycle tubing as used on the seat stays of a bicycle.
Joe Rowing used his Blizzard frame for trials, with no flex problems.
I’m sure he said what John said, that the stiffness of the two tubes was significantly greater than the strength of a single tube because of the triangulation of them.
Joe
The basic concept behind the Hunter/Telford/Vortex frames is the same for all three. Instead of using fat, low-end “cheap bike” tubing, on unicycles being built wider than all previous unicycles (wider tires at the dawn of manufactured MUni), use two pieces of high-quality bicycle tubing (as for a bike’s rear triangle).
As I remember it, the Hunter design came first, but Geoff Faraghan designed his Telford frame before today’s version of the Hunter frame was made (there was at least one slightly different prototype). The intent of the Telford frame was to imitate the seat post angle of a bike, so bike seat posts could be used, specifically suspension ones. Otherwise it was designed to look cool, which it did.
The Hunter frame seems to be a good, rigid design. It may look a little funny, but it does the job well. As much should be expected from an experienced bike frame maker like Rick Hunter.
The DM Vortex frame may have been thought as a logical extension of the thin tubing design into a more symmetrical shape. I also came up with that design, on paper, before I ever saw one.
So you have high-quality, thin tubing. This enables you to expand your “framework” fore and aft, while at the same time keeping your frame’s width to a minimum. This is especially useful for shorter riders. Now, not sure if this needs to be added or not, but if you added a hinge mechanism to any of these frames it would risk compromising their rigidity and would certainly undo any of the weight savings.
You guessed where I was going with this 
But I wasn’t going to put a hinge on it, don’t worry. One more question: it sounds like the Vortex frame isn’t as stable for Muni. Would it be stable enough on a 20" frame? I can’t tell how wide the gap is between the sets of legs on the Blizzard frame for comparison…