36" Oracle hub failure

That hub is a 125mm bearing width whereas you presumably are after a 100mm width hub for a smaller unicycle.

I found some people say nimbus oracle 36" has the strongest wheelset since it has 125mm bearing width. But it seems not true because of the aluminum hub? I’m wondering if it’s a better idea to get a steel hub 36er is a better idea. But the qu-ax RGB also has aluminum flange, and I don’t like the KH36 with crank mounted disks which make me feel not safe. What else 36er with disc brake and CrMo steel hub could I choose?

You can build up an oracle 36er with this hub at 125.

I have that and think it is going to be bomb proof and have the wider build option.

I’m just a beginner and lacking knowledge of building my own unicycle. I’m thinking that maybe a steel hub with 100mm bearing is better than 125mm aluminum hub? I found a cheaper 36er of a Chinese brand but could found any review about it. Any one has experience about it?

Ah yes I should have been clearer. By build I didn’t mean you do the building yourself. But you can get UDC or a wheel builder to do it.

I got my 36er built via UDC UK’s service with the steel 125 hub:

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The aluminum hub is serviceable for most riding not not recommended for very hard use. You can get 125mm steel hubs and Nimbus 36ers come Nimbus ISIS Disc Steel Hub - 36 Hole (125mm center bearing to center bearing).

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It would be better and wiser to invest in a quality uni from unicycle.com, at least you’d get some backup and support from a dedicated service.

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That’s one weird machine.

The company those cranks reference (Koxx One) hasn’t existed for about a decade.

Yeah, but I can change the cranks and saddle by myself. Then I suppose if the hub is isis cr-mo steel I won’t go too wrong with this machine, right?

I’m based in Taiwan and there is not a local unicycle .com. So I think the service will not make too much difference for me. And ordering a oracle 36 with a steel hub might cost additional charge. Since the only durability problem of 36ers I found on the intetrnet is the aluminum hub, so I’m wondering if it’s worth to built my own wheel. BTW, I’ve asked morality company and they told me that most of their components are also made in Taiwan. So I guess the quality might be similar?

It is a risk and chance. I’m one of those who likes to try anything before judge. If you buy it you could help others in your area to understand if it is a good deal or a bad one.

Actually, I prefer to buy the best unicycles of their specific category. The price is not really my concern since I found the off the shelf options in the market are not too expensive. I know building my own unis by combining components from different companies may create even better ones, but for now I would prefer to choose the best one available first and change the components in the future if I’m not satisfied. Based on this idea, I’ve purchased a M4O Tecno WRC 27.5 and a Trial machine.

As for 36ers, I now have an old no-brand steel 36er without a brake borrowed from a friend. I’m searching for something as durable, but lighter and with the disc brake. When choosing the best 36er, I found there are very few options there and they all have the downsides that stop me from buying them. I found that the crank mounted disc has caused some severe injury, so kh36 is out. And then I found that the aluminum flange of the hub may also have some problems. I actually hesitate a bit about the Chinese brand because of my national position. But as they stated, the components are mostly from Taiwan, and I think maybe if the material chosen is correct and the components are not with special specifications, I might not go too wrong with them since there are not too many components on a unicycle. Maybe one with aluminum frame and cr-mo isis hub double wall rim will make a light enough and good enough 36er.

Are you referring to where a rider installed what amounted to basically a saw blade on their crank?

There are both advantages and disadvantages to a crank mounted disk, but the chance of increased injury from one compared to one mounted on a hub is negligible.

The biggest disadvantage in my opinion is the torque being transmitted through the ISIS interface, which on a big wheel stopping fast isn’t ideal, and is far more torque than you’d ever put through the interface when just pedalling.

Yes, the injury caused by the saw blade disc seems scary, but I think a regular disc would also cause similar injury though might be less serious. The distance from leg to disc is quite different for disc mounted inside and outside of the frame. A disc inside the frame not only has more distance to the leg but also has the frame to provide additional protection. I think this might not be a problem for a skilled rider, but it might be a concern for a beginner like me.

I understand the concern but the likelihood of hitting the brake disc either if crank or hub mounted is very low. Bloody shins from hits by the metal spike in pedals is much more likely. Shin guards will protect from both type of accidents and I highly recommend them while learning or riding at your limits.
Also you can mount UCI approved brake disc’s as they have rounded edges for safety.

Thanks. I indeed wear shin guards when I don’t feel very confident or riding uneven terrain.

I agree with @Hammer. In my 10 years of municycling the worst injury I’ve had was 20 stitches in my calf from pedal pins. Not had any injury from disc rotor nor am I aware of any of my uni friends that have been injured from a disc rotor, inboard or outboard, ever. Very negligible risk of injury.

I hear this from time to time, but surely the interface load from hopping or drops is far greater than braking? It would be interesting to do some measurements and get some real numbers.

The rotor is in the same position as a chainwheel on a bike. I’ve never worried about injuring myself on a chainwheel, nor do I know anybody who has.

A (non-sawtooth) rotor isn’t really that sharp. I don’t see a reason to fear hitting it more than any other part of the unicycle.

I do sometimes worry about my trouser leg getting caught on the caliper and taking me down, so I tuck my right hand trouser leg into my sock. But only on my 36er, since I mix with traffic and don’t want any Unexpected Events.

Thank you all let me know that disc injury is rare. I might be a bit too conservative but the advantage of crank disc seems not appealing for me so I think I’ll still avoid it. BTW, I’m wondering if head injury is also relatively rare?

Head injury is relatively rare, but since it is pretty terrible when you sustain it, wearing a helmet is a good idea. (Pretty similar to bikes in that way).

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