I’m a motorycyclist (on my 9th bike, currently a Moto Guzzi 750) and with one exception early in my riding career, I have deliberately avoided wire-spoked wheels. On a motorbike, they are harder to keep clean, and you often (not always) need tubes rather than tubeless. A motorbike usually has far more power than it needs and for road riding, the slight weight saving of wire spokes is irrelevant. There is even an argument that slightly more weight adds gyroscopic stability. As a result, wire spoked wheels on motorbikes are largely reserved for trail or trials bikes (where weight is really important) or retro bikes, for the look.
As a cyclist who has toured and camped on 2 wheels, was once a keen tandemist, and who rides unicycles on and off road, I would always choose spoked wheels. They are lighter and have the right combination of rigidity in a straight line and slight flex if they hit a bump. Those moulded wheels with a few thick spokes offer no benefits that I can see. OK, so they may not need trueing, but if they ever do go out of true, they cannot be restored. I also think they look ugly.
Solid tyres: heavy and unresponsive. Weight at the perimeter of the wheel makes more difference than any other weight on the machine. The firmness and rebound are easily adjusted mid ride. Almost no vehicles use solid tyres in preference to pneumatic.
Lighter frame materials: The frame is a much smaller component of a unicycle, and therefore a slight saving of weight is less significant. The heaviest component on a unicycle is always the rider. Even a bottle of water or a bar of chocolate in your back pack would outweigh any weight savings from a titanium frame. Riding on the flat or easy tracks, as most unicyclists do, weight saving is only a minor issue, and saving it at the rim and tyre is more important. Of course, weight is important if you want to hop ad jump, but then carbon fibre can snap easily and dangerously. A bicycle frame is usually only subject to predictable forces along its axis and I have seen them snap nastily. A unicycle used for trials or serious muni is subject to a far wider range of forces and more vulnerable to breaking.
I’m really pleased that this forum has given you such tolerant friendly replies. There are many bicycle forums where you’d be shot down in flames!
I’m going to go off topic and then bring it back at the end
One thing I would never have predicted was the outboard disc (ie Spirit cranks/Mountain Uni UCM) being such a good solution for strong narrow wheels.
Most wheels I’ve built have been either zero or very low dish, either unicycles or internally geared hubs on bikes. I’ve never ridden a 125mm wide inboard disc hub and wouldn’t choose one because a highly asymmetric wheel is technically inferior in strength. It’s still probably far stronger than I’d ever need it to be though!
Perhaps we have made our assessments based on logic and rhetoric which doesn’t really stand up to reality.
Will I try a 125mm hub with an open mind now? Yes! Especially if there’s a KH/Schlumpf in the works! Do I want to see solid rubber tyred mag wheels for muni/trials/road? Absolutely not! They’d ride horribly and neither could be repaired.
It’s like choosing Goodyear welted boots with replaceable stick-on rubber halfsoles as your casual footwear. Strong, maintainable with a little effort and does the job extremely well.
You have proposed Carbon Fibre Crocs. Pay more, get less and can’t be fixed!!
Thanks for the thought experiment. I’d like to see you put your money where your mouth is!
Of course, some people have solid tyres on unicycles. They use the same rubber as is/was sometimes used on wheelchairs, and only because their wheels are bigger than the largest available pneumatic cycle tyre (36 inches). They usually report that the ride is harsh. I had the same experience years ago on a genuine Victorian penny farthing.
It is not beyond the wit of engineers to make a tyre from some sort of closed cell sponge that would soften the ride slightly. It would eliminate punctures, but at the expense of weight and lack of pressure adjustment.
As we used to joke in the MZ Riders Club, they’re easy for maintenance, which is just as well as you have to do so much of it.
On the other hand, you have no option but to spend lots of money when a modern “black box” fails. My most unreliable motorcycle ever was a BMW, with electronic problems affecting everything from starting to switching off the engine to using the brakes.
It would still not be able to compress as far as a pneumatic tyre. Impacts are distributed by the pressurised air right around a pneumatic tyre
The internal friction of the material would increase rolling resistance. I have a wheelbarrow with a foam filled tyre. Supposedly it never goes flat but in reality it rolls like it is never properly inflated.
Never mind the low density, strength, lack of fatigue and awesome corrosion resistance. Titanium is easily the most beautiful of all structural materials and looks every bit as good as the most expensive precious metals.
I have a Triton 36 because it was the first 36 I had seen on Gumtree/eBay in over two years of looking. I was very lucky to have the opportunity to buy such a beautifully customised machine. I did want something other than another blue uni but it was far more than I had dreamed of finding.
A month later I would have had an old KH instead … and then had to explain to my wife why I needed to buy the Triton too.
Donˋt think so much about weight, we already cut our bikes in half.
The reason for me why I ˋm unicycling is because it ˋs high fun and not high end.
George
I knew there were reasons for this, most people that have been into it for a while would already know. I was unaware, but now have a better idea of why things are where they are currently in the unicycle / cycling world.
I should have asked about airless options, not solid rubber. Sorry bout that. I most likely made everyone think I had heavy in my mind. I was thinking of an internal lightweight foam, sort of solid, but light.
Highly recommended. I have a V7 ii Stone. Before that, I had a V7 Stone that was stolen. My wife and I went to Motorcycle Live (a massive bike show) and sat on pretty much every bike that was not a sports, cruiser or adventure style and decided that the Guzzi was still the best, so we bought another. So much character.
I’ve seen these for cars. Looks like a really interesting approach. But while I can perfectly imagine this to work on a car, where your wheel is more than 20cm/8inch wide, I doubt that it offers enough lateral stability when being only as wide as a typical bike/uni tire. Maybe they’ll work for road riding? Dunno. But for muni or trials? Hard to imagine … but who knows what future brings?
A wheel constructed from laced spokes under tension coupled with a pneumatic tyre is one of the most elegant and efficient solutions to a difficult problem that humans have ever created.
The problem is to make a wheel light and strong enough for human power which is comfortable to ride in a simple unsuspended frame, stiff, easy to produce, maintainable and cheap.
There are a huge variety of compatible components available (spokes, hubs, rims, materials which deform gracefully or fail catastrophically, tubed or not, five or fifty psi, slick or knobbly, fat or not). This can either be part of the search for value and game of compromise that we play and enjoy or perhaps an irritating distraction.
No one solution is best and if you want one solution, it will only be the best in its own little niche. What niche are you trying to fill with this foam tyre/monolithic wheel sophistry?!
Please stand while I play a harp tribute to Sheldon Brown on the spokes of my 36er while chanting lines from Jobst Brandt’s ‘The Bicycle Wheel’.
Hint: there’s a reason for that. It’s been explained enough times here and on the other thread, but I’m still not sure you’re getting it, traditional spoked wheels haven’t been replaced on bicycles (and unicycles) because they’re the best solution for the job. In fact they’re an incredibly elegant solution using the same principles as in the most sophisticated structures. Where road racers use anything other than traditional spoked wheels the only reason is because of the aerodynamic benefit - not really an important factor for unicycles. As I wrote on the other thread, the only advantage of the “mag” BMX wheels you seem to like so much is that the look “cool” (if you’re into that sort of look), they’re heavy and weak.
Sort of solid, but heavy. Way heavier than a traditional air filled tyre. Not only that, but poor rolling and poor shock absorption - because with an airless tyre like that only the material at the bottom of the wheel contributes to the suspension, whilst with an air filled tyre all of the air contributes. Foam cored solid bike tyres have been around since forever and they’ve never taken off because they’ve always been pretty rubbish. TBH there’s even less benefit to them now than there’s ever been, given advances in tubeless tyres which reduces the amount of punctures you get - I’ve been running tubeless tyres on my mountain bike for 15 years and in that time only had a couple of punctures where I needed to stop and remove the tyre (lots of punctures which the sealant stopped, probably lots I never even knew about). Though I’m still just running tubes on the unis as I don’t seem to get punctures on those (if I did I’d go tubeless).
As for the carbon frames, I sort of agree with what other people are saying. There would be a small weight benefit, but they would also be easier to damage. I’m a big fan of carbon for bike frames - I have 3 of them, including my MTB which I’ve bounced lots of big rocks off without damage. However I’ve also written off a carbon MTB frame when the handlebars spun into it. The sort of impact you get with a unicycle might well damage a carbon frame. Having said that, if I had lots of money and time I’d probably get myself one built, just because.
I have a carbon unicycle frame, it’s great, and super light! Only problem is, it was made in 1998 or so, before people started using wide tires for Muni, so it doesn’t fit a wide tire. It mostly hangs as part of my collection now. It’s not an all-carbon frame; it’s made with straight tubing (pretty thick but still very light) and aluminum lugs. Roger Davies made a handful of them before the days of Nimbus and Unicycle.com.
I have a closed-cell foam tire. Correction; it’s an inner tube replacement, meant to be put inside a 20", BMX-sized tire. I think the major selling point was no flats. Of course it weighs quite a bit more than an inner tube plus some compressed air. I bought it because I was thinking of making a half-wheeled unicycle. It would be perfect for that. IUF founder Jack Halpern used to have a 1.5-wheel stack uni, with the half wheel on top. It was very interesting to ride, and quite a novelty! He brought it to the USA National Meet in 1982 and I was able to ride it, having learned to ride a “normal” 2-wheeler earlier that year.
To back up what aracer says this website has a run down on non pneumatic tyres as of 2014 and why they suck with a historical run down of the last 30 or so years and every other variant that has sucked and why. This should put this to bed for you once and for all Up_Right. Then again maybe the writer of the article is being paid by tyre companies and it is all a conspiracy to keep foam core tyres down.
Sheldon Brown: “Airless tires have been obsolete for over a century, but crackpot ‘inventors’ keep trying to bring them back. They are heavy, slow, and give a harsh ride. They are also likely to cause wheel damage due to their poor cushioning ability. A pneumatic tire uses all of the air in the whole tube as a shock absorber, while foam-type ‘airless’ tires/tubes only use the air in the immediate area of impact. . . My advice is to avoid this long-obsolete system.” Brown wrote that at least fifteen years ago, but I am certain it is no less true today.
And for those interested in weights here is a comparison of a bunch of 20 inch frames. The Koxx One Carbon which I think is the only commercially sold carbon fibre frame is barely a weight reduction on the current KH 20" and it also has a shorter neck which means you cant cut your seatpost down as far theoretically.
Saving 15g is barely worth it for the chance to crack your frame in half when you land standing on it after a 900 unispin attempt.
The Titanium frames are a bit lighter again but still the reduction is negligible. 30g saving when the wheel-set/seatpost/saddle weigh ~4800g
Especially when for that 30g saving you are paying double or more for the frame…
