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TECH NEWS
Bike at Bedtime Nubike - 1 (1)How does that work?!? Check out the chainless NuBike
The chainless NuBike is a design that has been around for some time now, but we thought we’d show it to you just because it’s so unusual. Some might call it downright strange.
NuBike is an idea from US inventor Rodger Parker. Rather than a traditional chain drive system, it uses two long levers connected to a gearbox that converts your up/down stepping motion into rotational movement at the rear wheel. That’s the gist of it.
The obvious question: why?
Rodger Parker claims that NuBike goes faster than a normal bike with less effort.
“The first advantage is leverage,” he says. “NuBike’s pedal cranks deliver two and a half times more power to the rear wheel using leverage.”
The argument is that NuBike’s longer levers deliver more force. Granted, a longer moment arm will reduce the moment force that you have to put in to get the same output, but generally we just use gears (as Nubike can) to control the input force independently of the output force, no matter the length of the crank or moment arm.
“The second advantage is the use of gravity,” according to the inventor. “The rider’s weight provides forward motion throughout the entire pedal stroke, not just for part of it.”
We've seen vaguely similar arguments for the use of Rotor Q Rings which are designed to enhance torque production during your pedal strokes, but that's a whole other can of worms that we're not going to get into here.
Rodger Parker also reckons that the NuBike system results in less drag and less maintenance, and says, “With linear motion, there’s less stress to the body, so less blood oxygen requirements to the legs, less strain on the heart, and less flexing of the hips, knees and ankles.”
If you’re cycling for fitness, part of the appeal is that it challenges your muscles and cardiovascular system, but Rodger Parker says that part of his motivation for developing the NuBike was that his wife “ended up with a knee problem likely caused by years of extensive riding”.
We're not going to go into a full critique of the science – this is just a quick Bike at Bedtime – but you can check out NuBike's YouTube videos for all of the claims and see what you think. We'd be interested in your comments.
We've not swung a leg over the NuBike so we can't comment on the performance. We can tell you that the use of treadle-type systems to transfer power to the rear wheel is far from new. The American Star Bicycle used independent treadle mechanisms back in 1880, for example, and then there was the more recent Alenax bike that prompted the late engineer and cycling guru Jobst Brandt to write, “I think the inventor (and investors) did not realise that converting reciprocating motion into circular motion is best done by a rotary crank rather than a reciprocating lever, and above all, they weren't bicyclists.”
There are plenty of other examples out there, but NuBike’s system has its own patent which says, "The mechanism includes a crank lever, which when forced by the driver’s legs, pushes a drive arm that, in turn, rotates a drive wheel. The rotation of the drive wheel transmits a torque to the bicycle’s rear wheel via a gearing mechanism.
“This invention is… a bicycle propulsion mechanism... whose crank levers are much longer than those of a conventional bicycle, provide excellent ergonomics, makes a highly efficient use of the power transmitted by the rider, and which uses relatively few parts for a smooth, reliable, and highly adaptable mechanism."
The patent claims that "one improvement offered by the invention is that many frame elements in a double-triangle frame configuration, such as a chain stay, seat tube, bottom bracket, and down tube, can be eliminated and [it] thereby allows a reduction in weight.”
A built-in mechanism “prevents horizontally opposed lockup of the drive levers by advancing one pedal at the top of the stroke and retarding the opposite pedal at the bottom”, according to NuBike. This is also designed to provide “a smooth, natural transition from one stroke to the next”.
Rodger Parker reckons that a carbon-fibre NuBike frame weighs less than 1.36kg (3lb) and the gearbox that converts linear pedalling to rotational motion “weighs less than the chain and sprockets of a 10-speed”. A complete road bike is a claimed 8.16kg (18lb).
When it comes to fixing a flat or putting NuBike into the back of a car, removing the rear wheel is said to be quick and simple: you just open two quick-release levers and disconnect the shifter cable.
What about hills? The patent says, “The invention is adaptable to bicycles using a conventional gear cassette, an internal gear hub, or any of the numerous gear configurations known in the art.”
You’ll see that “known in the art” phrase in patents all the time. It simply refers to designs that are already out there.
The NuBike in the video (above) is a 4-speed system that allows you to customise your ratios. The design also lets you coast.
> L-shaped cranks — explore the crazy idea that just won't die
Is NuBike ever going to set the market alight? Don't hold your breath for that one. When looking for £275,000 investment on Kickstarter five years ago, it received pledges of £3,000 so funding was unsuccessful. Be honest, though: you'd still like to give it a quick blast, wouldn't you?
Latest Comments
- Hirsute 3 sec ago
A man who tried to send 500 bikes to a charity in Africa had them refused at a Scottish port after they were classed as waste....
- Clem Fandango 7 min 16 sec ago
Motor normative nonsense. I bet you're one of those drivers that crash into other road users all the time because you have to constantly focus on...
- Andrewbanshee 27 min 43 sec ago
Where I live we are experiencing a lot of housing development on small and large plots of land. These developers don't seem to have problems...
- slc 29 min 52 sec ago
There is a spot in the River Avon which seems to attract bikes and scooters that have been chucked in. At low tide it looks like an archeological...
- hawkinspeter 33 min 59 sec ago
Sometimes peanuts
- Homebaker 1 hour 50 min ago
Oh you can't block roads, what if I need to drive my elderly aunt to the emergency hospital, and even though there are better routes, I want to go...
- mdavidford 3 hours 22 min ago
The answer to this is to have no friends.
- Backladder 5 hours 15 min ago
While original sash windows are nice they make it very hard to keep the house warm, we eventually went for upvc double glazed sash window...
- Steve K 6 hours 39 min ago
Other drivers only care about disabled people when it gives them a way to object to cycling infrastructure.
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33 comments
So at the moment when I'm putting in 200 W at the pedals the rear wheel receives roughly 195 W due to drivetrain power losses, by that statement I'm now going to get 500 W at the rear wheel for the same effort? I am no expert but I think the laws of thermodynamics might have something to say about this.
I think Archimedes already would have.
No mention of how it performs on hills.
All the videos seem to show people riding it on flat ground.
I suspect there is a reason for that...
We had a guy on the Amsterdam Velodrome during the 90's with the exact same drivetrain but as a trackbike.
Would like to see some world class sprinters rip this thing apart. Its a fun design but would not trust it with my life.
Disappointed that no one has suggested L-shaped cranks would improve this design yet.
But the article above has a link to road.cc's very own one on the topic, just near the bottom...
Hoping to see a combo of this in your Christmas gift ideas this year - Gizmo-ears-shaped seat, with an eliptical ring driven by some kind of arm-with-a-kink-in-it system. Ideally with some overcomplicated tech so that close-passing drivers can get a readout in lights on your clothing of exactly how many watts you're pushing, to the nearest 0.01 W. Plus bike should also incorporate a mid-mounted tent (with aero-improving design) and come in a shade under 15K.
It will then be shot down by road.cc readers because it lacks the mountain capabilities of a full-sus bike or it's 0.5 seconds slower over the average shopping trip.
Everytime someone visits the L-shaped cranks page, a baby squirrel gets shot
Win win!
Gold plate it, brand it Chump, and sell it to MAGA Morons.
It looks like a 21st century version of something built in the 18th century…
(edit) Sorry, may not have been clear. I meant - imagine if Geoffrey Godfrey Higginbottom, Esq. had been given access to plastics and carbon fibre.
Ah yes. The Higginsbottom perambulatory engine.
Reminds of this, which has the advantage of being something you could actually go out and buy if you were so inclined.
A disadvantage of that system is that there is a return spring on each side which will consume energy that is lost and does not contribute to the forward motion.
There's a wonderful explanation of leverage here: https://youtu.be/ldcdiu82-_Y?t=34
If riding a bike involved lifting a kettle bell attached to a chain then great but it obviously involves sprockets and chainsets that do exactly the same job as his long lever but possibly with less metal overall.
A big issue with his design is that it still needs a gearbox to connect his small crank to the drive which has its own problems such as weight, size, bearing strength and torque limitations which will be problematical in particular for mountain bikes.
With this explanation of leverage he is assuming most of his audience are fools which is never a good strategy. That is probably why his Kickstarter bombed.
Of course I would like a quick test ride. Cleaning a chain is something I am very bored, so I am very open to new ideas of anything that will make us get rid of it.
To be honest though, all such designs until they catch on and get on a big serial production to drop prices, they will be super expensive so out of reach for commuters.
*Atrocious French accent* We already got one!
I would be really tempted now to buy a belt drive for this reason. Not sure though how much efficiency would I lose both from the belt and the gearbox. On the other hand my often dirty chain must not have the best efficiency.
Nevertheless the major turn off of belt bikes is their price as they practically have double price.
Double the price, but can do double the distance.
Pros and cons - I'd say they're best for particular applications.
Mine's for a (relatively) efficient commuter / general transport. And since I'm only now commuting to work from home and don't run a power meter on mine it doesn't need to be race- or audax- efficient. If you want gears, that's going to be a hub-gear system and that will determine the overall mechanical efficiency, not the belt. (Alfine is good enough for my use. Shell out for a Rohloff one and it should be about as good as a standard deraillieur system all told).
For me the "efficiency" also includes "less time cleaning / faffing / getting oil off trouser legs". (Also applies to hub gears).
Down sides - you now need some system for tensioning - so that's sliding drop-outs or an eccentric bottom bracket. I have the latter and mine is definitely way more creaky than anything else I've ridden. I'm getting used to it but it's still a bit concerning and I know that's a deal breaker for some people.
I've only had 2 instances of bike vandalism in my whole life, but I'm always slightly concerned someone will take a razor to the belt - and you can't just walk into a store and get a replacement. Changing gear ratio is also more tricky as you can only get certain combinations of belt length, "chainring" and sprocket.
You need a frame you can separate at a seat stay, to fit the thing.
Maybe another con (for internal hub gears), is the effect of low temperatures. This winter, commuting in sub-zero temperatures on the city bike with Nexus 7, it actually got to a point where I couldn't shift out of 5th gear. I think the oil in the hub got too viscous once it got down to -5 deg C. No problems with my fast commuter running a 10spd Deore derailleur.
I didn't notice any issues with my Trek District that has an Alfine 8 at -8 °C. I did have issues with my conventionally geared fat bike at very cold temperatures (below -20 °C) where the freewheel stopped... freewheeling. I had to keep pedalling like it was a fixed gear or all the chain would come across to the top and derail. I replaced the hub oil with special low temperature oil.
Worryingly that is a decreasing problem for many...
I have heard of this but (in my short time using one) never had issues. For those folks in continental climates (especially the US) OR who have a yen for Scottish winter mountain trips perhaps...
Not having to tangle with oily chains or exposed drive components - for "transport" purposes that's a massive win as far as I'm concerned! (Combined with going to disc rather than rim brakes it really makes for a cleaner, less fiddly machine).
Next time my frame breaks at the offside rear dropout I'm intending to get it rewelded with more strength and a frame splitter put in on the drive side, for putting in a Gate's for use in the winter. Quite happy for a chain for the less filthy months.
I'm on my third frame, so only a matter of time.
Yet to have a problem with the Rohloff in the cold.
It's disingenuous to be claiming advantages from the use of levers (mechanical advantage) and gravity. With gearing, we can specify what mechanical advantage we want with ordinary bikes and bigger isn't necessarily faster. The thing with gravity is what goes down will need lifting back up again to complete a cycle, so there's no advantage at all unless you only want to travel a very short distance.
Claiming that it is faster is easy - let's see it in a race against an ordinary bike. It's notable that his YouTube channel doesn't feature any direct comparison of the bike being ridden.
Yes, there always seems to be some logical fallacy involved. Let's face it, on a human powered machine there's no free energy.
It's not a good look for the inventor to have to resort to saying things like that either. To be honest, if someone came up with a design that was lighter and faster than a typical bicycle, they could just get a bike company to try it out and then they could retire on their patent license fees. Resorting to KickStarter implies that it doesn't work very well.
I thought the title said "chinless"
These things always remind me of an article in Bicycle Quarterly about such another novelty bike (a shaft drive contraption) that sunk the fortune of a US family clan in the 1880s. Tagged on was a short piece on a recent re-inventor of the bicycle, entitled "Still at it after all those years". That phrase always traverses my mind on these occasions.
2022 - "NuBike tried a 30-day funding round on Kickstarter in which they aimed to raise $347,000, quite an ambitious goal. Unfortunately, they only managed to raise $4,000, 1% of what they had planned. The project was a massive failure." https://www.autoevolution.com/news/the-nubike-is-a-chain-less-bicycle-th...
Looking at the Kickstarter and I don't see how it could possibly met its target. The goal was $347,000, but there were only 50 bikes available for $3600 each. $3600 X 50 = $180,000. So it looks like the only way it was going to reach the goal was if they sold a few thousand baseball caps at $75 each, which seems rather unlikely.
Judging by some of the claims made about the bike, I'm thinking maybe science/maths isn't Mr Parker's strong point.
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