12

marketing picture of a Cyclotron bike, from their website

You've probably seen these weird hub-less bicycles, the Reevo and the Cyclotron; while they "look cool" I wonder if anyone has long term maintenance experience on these. Considering that normal hub/dérailleur systems ought to get re-greased and fixed, and any stripped cogs replaced, every 10 years or so, I am not sure I believe the "maintenance-free" claim.

Is this bicycle design too new to be familiar with any bike repair shops... or is the verdict still out on the long term reliability on this design?

14
  • 16
    Do these bikes actually exist? All I can find is pictures that look like raytracing renderings or photos of clay model, old Kickstarter and Indiegogo campaigns and complaints about manufacturer disappearing.
    – ojs
    Nov 11 '20 at 16:17
  • 2
    Bicycles are a very mature technology.Wire spoked wheels might be hundreds of years old but it turns out they are the best arrangement for light weight and strength. If hubless wheels were a better solution than spoked wheels they would be commonplace already. Nov 11 '20 at 16:23
  • 2
    The mechanics if these are nonsensical because of the large diameter wheels high leverage acts on the 'bearing' points. even more so through impacts on rougher roads.
    – Carel
    Nov 11 '20 at 16:24
  • 1
    The videos for Reevo look real to me. I guess the design works enough for shooting a promo video if you throw enough materials at it. No information about how much the bike weighs, so I guess it's extremely heavy. Maintenance is probably going to be tedious.
    – ojs
    Nov 11 '20 at 16:29
  • 1
    This isn't a "hubless" wheel. It simply has a gigantic hub that's nearly the same diameter as the wheelset itself.
    – FreeMan
    Nov 12 '20 at 13:56
30

Verdict seems to be 'this is a scam'

Cyclotron is a scam https://cyclotronscam.boards.net/board/1/general-discussion

Reevo is suspiciously similar

https://www.reddit.com/r/shittykickstarters/comments/ivk95y/reevo_hubless_ebike_anyone_know_anything_about/

Comments on there about sum it up: looks good to the gullible on Facebook/Kickstarter, in reality is much worse than existing solutions. Hubs & spokes work just great, spokes are fantastic things in that they are each in tension making the wheel strong and repairable.

https://www.cyclist.co.uk/in-depth/85/the-science-behind-spokes

The 'advantage' here seems to be 'not having basic physics on my side, but looks cool'.

One such bike was made an art school product; I suggest that is as far as this will get

https://www.flickr.com/photos/laulaulau3/31994357/sizes/o/

Until these things are actually available and in people's hands, it's best to work on the basis that this is either an outright fraud, or at best will be a terrible piece of junk that works incredibly poorly.

I'm not going to hold my breath to see if my instincts are wrong. But I'm glad you posted this, because I saw these on Facebook and immediately thought 'lol, scam', and now I've done 10 minutes research I'm feeling pretty much confirmed about my theory. But then I am a very cynical person, so.

There is a bit on hubless wheels in general here: https://en.wikipedia.org/wiki/Centreless_wheel Essentially they are a problem looking for a solution

Edit: I had a look at the technical names given here: https://www.indiegogo.com/projects/reevo-the-hubless-e-bike#/

CEO might have relevant experience https://www.linkedin.com/in/alec-lim-6877821b7/ but it doesn't appear to relate to bicycles or motor vehicles, maybe only robotics

Lead engineer seems to work on microchips in Italy https://www.linkedin.com/in/andrea-stona-87984739/

CTO seems to work for Osram as his day job on lighting, connected lightbulbs, etc. https://www.linkedin.com/in/chewivan/

I get the impression there are a few software people there; how much work they are doing is not clear, but there doesn't seem to be much if anything in the way of 'people who could reinvent the wheel'

11
  • 2
    From Wikipedia: "One real-life example of hubless wheels ... Tron " :) lol Wikipedia is great for disinformation but the other links are quite informative, thanks for the writeup.
    – NoBugs
    Nov 11 '20 at 18:25
  • 2
    There was a real hubless front wheel called the Black Hole. One problem with this design is that it's not hubless; instead, you wind up with a rim-sized hub. In the case of the Black Hole, I believe the rim rode on 4 rollers positioned around the circumference (which may have ridden on bearings, in turn).
    – Adam Rice
    Nov 11 '20 at 18:55
  • 12
    I can see a possible advantage of hubless wheels. You are riding your bike down the road in a warzone, someone fires a shoulder mounted rocket at you from the side. Hubless wheels have a big hole in the middle for the rocket to go though, so it has more chance of missing you. :)
    – mattnz
    Nov 11 '20 at 19:30
  • 4
    @NoBugs you didn't read the article very closely. The Tron bikes mentioned in the article are real street-legal motorcycles with hubless wheels, made to look like the ones in the movie Tron: Legacy, that were sold to the public.
    – rclocher3
    Nov 12 '20 at 2:14
  • 3
    @mattnz and that soldier would get a bollocking for wasting an expensive rocket round on a soft target that only requires a burst from a rifle. :)
    – Criggie
    Nov 12 '20 at 2:23
20

I would think about these in terms of bearings: The hubless design moves the bearing of the wheel all the way out to its circumference. As such, you get

  • extremely long racetracks

  • a need for many more bearing balls/rollers

  • the bearing balls/rollers rotate much, much quicker

  • the seal for the bearings must be much larger

  • the bearings are much, much closer to the road with its water, dirt and grime

  • not bearing related: the forces from the ground are transmitted to the frame along the loops of the wheels, requiring more material for the same structural strength

This boils down to much more material being needed, much more wear on the bearing balls/rollers, much bigger headaches sealing the bearings, and thus much higher rolling resistance than what is achievable with a hub based design.

In addition, you loose the slight suspension effect from the spokes.

So, all in all, its just a lot of cons for essentially no pros. I wouldn't buy such a bike.

2
  • 8
    The other issue is that a normal bicycle wheel gets its strength from tensioned spokes. If the inner hoop of the hubless wheel is built to similar strength as traditional wheel, it is going to be heavy.
    – ojs
    Nov 12 '20 at 9:03
  • 1
    @ojs Right. I have added that to my answer. Thank you. Nov 12 '20 at 9:43
3

I agree with thelawnet that the hub&spoke design is actually really great for a wheel, and hubless throws that away somewhat needlessly.

However, if you look at hubless as essentially a big passive hoop around a smaller wheel at the bottom, it's clear that it can in principle work just fine. As in e.g. roller skates, very small wheels are in principle enough to carry a person – the disadvantages are

  1. very small wheels won't roll over any sizeable obstacle
  2. lack of cushioning by an air tyre
  3. smaller wheels rotate at higher RPM, and would therefore require a higher transmission ratio for same speed at same cadence.

Points 1. and 2. are addressed by the hoop-wheel. As for point 3., while that is a disadvantage for a bicycle, it is actually a significant advantage for an electric vehicle: whereas humans need long transmission to get good speed out of the low cadences the legs can achieve (whilst having plenty of force/torque), electric motors have no problem with high RPMs at all and instead need very short transmissions to get decent acceleration/climb out of the low motor torque. Thus, for an e-bike, starting with a big wheel and long transmission and then gearing it back in a mid-motor is actually pretty stupid. The hubless design does largely remove this back-and-forth conversion.

5
  • As someone whose preferred bicycle brand is extremely fond of 16" and 20" wheels, this is me looking at you sideways for point 3 -- small (conventional spoked) wheels' worst downside is that they're worse at handling potholes. The gearing ratio changes are great for hill-climbing and cargo-hauling; and modern internally-geared hubs have a wide enough range that top speed isn't really a problem either. Nov 12 '20 at 14:45
  • @CharlesDuffy "worse at handling potholes." That was point #1. Also you and OP both missed my main small-wheels gripe: less deceleration is required to faceplant over the bars. And I say this as a regular 20" rider. You're right, though, about the gear ratios; they're easily tuned. My current 20" has a 52t chainring.
    – Michael
    Nov 12 '20 at 18:34
  • @Michael “less deceleration is required to faceplant over the bars” – that's not really a function of wheel size, as much as of bike geometry. It just so happens that a) bikes with bigger wheels tend to have (for obvious reasons) longer reach too, and b) bigger wheels are better at avoiding such big decelerations in the first place. Nov 12 '20 at 20:32
  • nod. Part of what makes Bike Friday interesting is their custom frames -- have a full-size bike with a given handlebar/pedal/seat geometry? They'll replicate that in a folder. And the "better at avoiding big decelerations" is a two-edged sword; having more angular momentum also means slower starting and stopping. Nov 12 '20 at 22:16
  • 1
    The Cyclotron is actually worse than small wheels at handling obstacles: If you look at the video where the clay model is ridden, you'll see that there is a fixed fairing around the entire wheel with small hole at the bottom. If you hit any kind of bump, it's the fairing that's both damaged in the impact and is stuck to ground.
    – ojs
    Nov 13 '20 at 13:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.