I know the difference between Trials and Mountain Unicycling, but what is the difference between the unicycles designed for said activities?
Well, Mountain unicycle’s usually have about 24x3" tires. Trials usually have 20xsomething" tires. I’m sure there are other differences, but I don’t know them.
To me the difference is that the Trials unicycle is intended specifically for Trials, which means it doesn’t have to go very far. A mainstream MUni is intended to cover ground, which means either a bigger wheel, shorter cranks, or (usually) both.
A MUni can double fairly decently as a Trials cycle, if it’s strong enough. You’re just throwing a lot of extra weight around. A Trials uni, however, is probably not very fun for any kind of distance ride, unless you’re riding with a group of people on 20" wheels.
Beyond that, the Trials uni should be able to withstand an infinite number of hops. This means real strong axle and crankset, good handle, and a solid connection between the two (seat, post, frame). On a MUni, depending how you ride, you may not need those elements to be as strong.
I agree with most of what John has said, although I am not sure about the crank length comment. I only have a MUni and have never ridden a Trials Unicycle, but as far as I am aware the common tendency is to use shorter cranks on a 20" than you do on a 24" Unicycle. Unicycle.com reckons 170mm cranks are best on a 24x3" MUni to get the maximum torque for climbing and descending hills. 170mm cranks would constantly hit the ground on a trials Uni, and some people find even 145mm cranks too long for trials. I guess John might have been talking about 26" or 29" MUnicycles when he mentioned the short cranks, because I have not really taken them into consideration (and John has thousands more Unicycles than me). Bigger wheels often use shorter cranks to attain more speed while sacrificing control. On UNiVERsE most of the trials riders use 20" Unicycles, but you see Kris Holm using a 24" for trials stunts. Both of these types of Unicycles, Trials and MUnis are usually built much stronger than novelty or learner Unicycles, and are made using fat parts with agressive/abusive riding styles in mind.
Yes, my reference to cranks was off. A 20" wheel is generally going to have much shorter cranks than a bigger wheel, depending on the use of the cycle.
The common optimum size for 26" (or 24 x 3") is 170mm, but if you ride a lot of rolling or easier terrain, 150 or even shorter cranks can be used.
On a 20" Trials uni, 145mm is probably as long as you’d want to go. Even then, normal street riding will have you hitting your pedals on the ground a lot.
I think when the Universe was made, Kris was not yet using 20" wheels, so you don’t see much of it then. In fact, the use of Trials wheels was just getting started then, and Dan and Adam were probably among the very first riders to use them.
Nowadays, Kris can be frequently seen on a 20" when doing Trials moves.
Completely untrue:
Once you get the hang of yourself going more slowly than on a bigger wheel, as long as you are riding as fast as it can go, (comfortably fast, still maintaining control) you soon find that it’s ‘fast enough’
Then, take that trials uni to a hard-packed MUni trail. It’s a blast, and a completely new experience. Doesn’t handle so well in the mud though.
I’ve found that if you have several style-specific uni’s, it’s really fun to see how many barriers you can cross with each one. Trials on the Coker is proving quite fruitless, though.