More dumb questions...

I am not a real cyclist (but hope to become a real unicyclist) and not as up to date on the technology etc. as most people here probably are. I am big on simple well built things that last long and need as little maintenence as possible

  1. Wheels.

I view steel spoked wheels as someting that should have gone out of date long ago. I remember them being a hassle in my motorcycle days, and really liked that they were avoidable on road bikes.

I do wonder why these have not been replaced long ago with 3 or 5 spoke set ups like some BMX machines have, and are not the industry standard?

  1. Tires.

Why not never get a flat solid rubber tires? I used to find getting and fixing flats cycling and motorcycling and dealing with a flat in a ride to be a hassle. http://www.tannus.com/

  1. Advanced materials

I see titanium frames and mentioned once in a while. Not much about carbon Fibre. Has anyone ever made a frame or wheel set etc. out of this or other more interesting high end material? How did it work out?

This question has been answered to you in the other thread. Spoke wheels offer still the best weight to strength ration. The next step in the evolution are light textile rope skokes or carbon fiber spokes. Theese clumpy plastic wheels ride really bad and haveto be replaced as a whole. You only find them on the cheapest of the cheap unicycles. In my eyes: absolute crap

Solid rubber tires are more heavy and offer mostly poor suspension and damping characteristics. If you want better flat protection, go tubeless. That said: I’ve never had a single flat on all of my unicycles.

There have been carbon fiber frames and you can buy carbon fiber rims and saddle bases. They’re all very stiff and very light. But also extremely expensive and prone to cracking when crashing. For rims and saddle bases it makes perfectly sense (if you have the money), but I’d make no other part of my uni from this material.


Don’t think so much about all of theese questions. Go out and ride more! If you spend all the time on your uni that you spend with messing aournd with all of these questions about rm holes, spokes, etc., you would have more benefit than from building the “perfect” uni. (that said: I consider a uni like you suggestd above with solid wheel, full rubber tire and all made of carbon far far away from perfect.)

There have been some improvements in strength to unicycle parts. I had multiple seat post failures prior to upgrading the seat post to something better than stock. Also, there are a few models of cranks with inserts where the pedals screw in. I have a pair of Impact Eiffel 140mm cranks with these inserts, and the pedals have never budged when I tried to re-tighten them.

Some equipment problems only manifest themselves once we learn certain techniques. For example, my stock Oracle seat turned to mush after I started pushing and pulling hard with one hand on the seat handle. And spokes started breaking after I learned to hop and started using it frequently as a corrective measure.

I had a few problems because I didn’t understand the ISIS specification, specifically that a “stop” is a part of the specification. The spacers need to be sandwiched between the cranks and the hub. There should be no extra space.

Back to the “little maintenance as possible” notion: If you’re a bigger rider, you need to check the tightness of things frequently, especially when the unicycle is new or when the parts are recently installed. You’re going to have to expect a certain amount of maintenance just to get things dialed in. For example: experiments with tire pressure, raising and lowering the seat post, adjusting the angle of the seat. When I started using bar ends, I spent a lot of time reconfiguring and adjusting the bars.

Spokes are the overall best option, simple as that. That might not be the case for bicycles, but it is the case for bicycles and unicycles. (Aside from a very few high end roadbikes.) Most people don’t want to buy a new wheel when you hit the curb a little too hard.
It is also relatively easy to manufacture good spokes, a good hub and rim, and the using the adjustment spokes offer to make a very round wheel. Moulding a whole bicycle wheel at once is not as easy, making a 1 meter large and dimensionally accurate within half a millimeter part from carbon fiber is difficult.

I kinda like being able to choose the “spring rate” and suspension preload of my tire, you can’t do that with flat solid rubber tires. The actual dynamic behavior of air tires (and solid rubber tires too, for that matter) is relatively tricky, but the air in a tire can act more like a spring, and absorb high velocity impacts, while rubber acts a little like a damper, and stiffens with higher velocity impacts (like a bump in the road produces). The overall ride quality you can achieve is better with an air tire.

You can absolutely make carbon fiber frames and wheels. But currently, paying a whole lot of money for a marginal weight loss is really not worth it.

The only valuable measurement on whether a unicycle part is good or not is what I call the “Fun-Cost Ratio”. I would buy a trials unicycle with an aluminum frame, because the saved weight (and better stiffness, alongside a better geometry) makes riding a lot more fun. I would not buy a lighter rim for my Muni, because it’s fun to ride as is, and a lighter part wouldn’t change that much.

lol, I’m picturing this super-light, fragile carbon frame, paired with a heavy mag-style wheel and a solid rubber tire.

Maybe take one for the team and build it. At worst you have a hilarious piece to take to conventions and have as an example of why you don’t build that way, and at best you’ve got the amazing wheel you want. Custom unicycles are always cool, whether they’re smashing success or not.

If carbon parts were as delicate as folks on the forums say, the mountain bike trails I ride would be ankle deep in busted frames, forks, cranks, handlebars, etc. :slight_smile: People use this stuff. A lot.

In skis, bows, golf club shafts, pole vault poles, Corvette springs, etc, the springiness of composites is a feature. It takes a lot of carbon to make bike parts that don’t flex and are stiff enough to be effective, and they seem just about bomb-proof once you do. I’d guess it’s more that the basic hand-laid composite technique is labor-intensive and also probably not so dimensionally accurate, while the methods used for mass-market bikes and parts call for tooling that couldn’t be amortized over the tiny niche-of-a-niche market that is premium unicycling.

For wheels, the applications where people care the most about stiffness and unsprung weight–high-end sports cars, formula racers, and road-racing motorcycles–all use cast magnesium, with maybe some composite presence creeping in while I haven’t been following closely. In the pro cycling peloton, it seems to be low-spoke-count high-tension spoked wheels with deep-section composite rims. Pro cyclists complain about poor grip on rough surfaces when they use their more rigid disc aero wheels, which says that they count on their spoked wheels as a form of suspension. With our wider tires and lower pressures, that shouldn’t matter as much to us. Price and especially tooling cost has to figure in again.

Well, for one, bikers don’t go down as often, but carbon frames are undeniably more delicate than steel or aluminum. One hit on a rock and you can cause hairline fractures that you won’t notice until your frame explodes. My brother had a $3500 cross frame ruined from a single rock that got kicked up and caught between the crank and the frame while he was pushing. The internal damage to the frame wasn’t repairable at the bottom bracket.

If you don’t believe me, go check some stories out yourself:

Conversely, I’ve taken my surly and nimbus frames over rock gardens and had them literally flipping and twirling while hitting rocks down the side of a slope, and I picked it up and kept riding. You can see at the very least see the damage caused in most cases.

As you say, composites can be flexy OR stiff. When a rock meets stiff carbon, it’s going to win. The only place I see carbon frames being viable is for road riding. I’d buy a carbon v-frame for the 36er in a heartbeat.

I suppose one day eventually the techology will make some of these things more viable.

When I was into motorcycle trials in the 1970’s, they were all air cooled, twin shocked and drum braked. I correctly predicted one piece alloy frames with fuel tanks built into frames, monoshock, disk brakes, liquid cooled gas engines, electronic ignition, and electric powered units. All my fellow riders thought I was wrong and crazy etc. The one thing that did not come to pass was the elimination of traditional wheel spokes. A few machines had them, like the Merlin DG-3.

So we will see what eventually happens in the future to parts in the cycling, and unicycling world.

The plastic pedals I used to upgrade on my unicycle are considerably lighter than the metal ones they replaced.

If well made, light and durable I would prefer a one piece wheel where the rim, spokes, and hub are a single part. I would have thought that the techonology to make a cost effective better lighter maintenance free wheels like that is long overdue. It is not here yet.

It was only fairly recently that hubs became strong enough to be used for Muni at a resonable price.

I have had numberous flats, and broken spokes on my off road motorcycles. I would never buy a road bike with spoke wheels.

In motorcycles, you had to mess with points until they were replaced with pretty much zero maintenance electronic ignition. Antique motorcycles are a never ending series of constant maintenence.

I do agree with Jungleaddict. Unicycles fall a LOT more than bikes. In terms of flatland/street there is sooo much scope to land with all your weight in the middle of the neck of your unicycle while it has one pedal and the saddle on the ground. Surely that would put way more stress on the frame in a direction that it is not meant to in a way that bikes don’t really experience.

In muni I think we have more falls that involve the unicycle smashing into the ground than MTB’s do.

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 :slight_smile:
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.:wink:

The electrical gremlin that plagued British vehicles used to engrave his name on any equipment he fouled.

His name was “Lucas”.

carbon fibre, titanium …

Donˋt think so much about weight, we already cut our bikes in half.:slight_smile:
The reason for me why I ˋm unicycling is because it ˋs high fun and not high end.
George

If I get back into road motorcycling, I would most likely go for a Guzzi too.

The Prince of Darkness.

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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.

High fun, and not high end. Well put!

I like my things to be simple and durable.