HNF eBike Makes Use Of BMW i Swing Arm


OK, get your geek-goggles (nerd noodles?) on, and take a look at this.  This is a floating swingarm design that allows the pedals, mid-drive and belt to all live in harmony and peaceful co-existence with each other, yet remain a moving swingarm suspension unit.  From the BMW press release:

The drive unit swing arm is a new kind of frame technology for full-suspension eBikes featuring a mid-motor. The concept allows the drive train, which was previously firmly attached to the main frame, to float freely, eliminating the need for the conventional chain tensioner. This permits for the first time the combination of a rear suspension and the durable, maintenance-free carbon belt drive on full-suspension eBikes, resulting in outstanding propulsion and handling characteristics.

The BMW i patent for the drive unit swing arm principle facilitates for the first time the integration of mid-motor, gears and belt drive into an innovative suspension module, thereby dispensing with a belt tensioner.


The Heisenberg XF1 suspension detail

Apparently, this was developed with automotive applications in mind, but then had no real product targeted – thus the release of the patent to Heisenberg.

Heisenberg XF1 blet drive detail

Heisenberg XF1 blet drive detail

This gives the bike the following:

  • Mid-motor and even axle load distribution
  • Maintenance-free belt drive with hub gear, without chain tensioner
  • Highly stiff frame
  • No pedal recoil
  • Grip and traction in all riding situations, as there is no stiffening of the rear arm swing
  • Possibility of implementing a modular drive system
  • Freedom in the design of the main frame

While your geek goggles and nerd noodles are on, we hope your credit limit is plugged in too – HNF Heisenberg, (under founders Michael Hecken, Karlheinz Nicolai and Benjamin Börries), doesn’t cheap out on their innovation.  This mechanical wonder will hit the market at €8,345 ($9,200).  That breakdown, (according to a comment on Green Car Congress) likely amounts to: E-bike: €1,000, Four-link drive arm mechanism: €1,000, BMW logo: €6,345.

Interestingly, this design harkens back to the old one-piece motor-final drive swingarm of the venerable Honda Hobbit, Cub, mopeddy thing where you get the motor, swingarm and drive chain all enclosed in one piece suspended from the frame.  What is old, is new (and electric) again.

Get your orders in to HNF Heisenberg here, on their site, and you can read the whole press release from BMW here.

Category: BikesBMW


12 responses to "HNF eBike Makes Use Of BMW i Swing Arm"
  1. wavelet says:

    This type of suspension is totally unnecessary for bicycle-type vehicles (electric or otherwise); the price is simply unconscionable.
    Yet another concept that exists simply for cheap-ish PR.
    Boo to BMW for having any involvement with this.

    1. Nix says:

      “unnecessary”? Well, in the purest of terms, no, it isn’t “necessary”. Bikes without any suspension at all have fulfilled basic utilitarian needs for decades and decades.

      But when it comes to high-end full-suspension performance electric mountain bikes, it is a whole different story. There are plenty of full-suspension electric mountain bikes with similar price tags.

      As it turns out, there actually IS a significant problem that this solves. One of the long-time issues with making a center-drive full-suspension mountain bike work, is the pivot points for the rear suspension.

      In a perfect world, the pivot point between the bottom bracket and rear triangle should be very close to the center of the crank spindle. This gives the rear suspension the best performance (especially under pedaling). But center-drive systems often take up a lot of space around the bottom bracket (for example the Bosch Mid-Drive system). That pushes the suspension pivot points far away from their optimal positions.

      This design completely eliminates this problem, by virtualizing the pivot point. This isn’t simple stuff you figure out by trial and error in your garage. This takes lots of computer force-analysis and CAD-CAM work, which is where a big company like BMW comes in handy. BMW already has the suspension software and expertise in their Motorcycle division, so they are a great partner. I would actually bet that BMW put way more resources into this than they will ever get out in the sales of these bikes.

      It is actually a very nice piece of engineering designed to appeal to folks who might drop $8-10K on full suspension mountain bikes that don’t even have an electric motor. They are only selling a very limited number of these, so they are more of a “Halo” machine.

      If you think their full-suspension bike is too extreme for your needs, it looks like they also sell more basic bikes starting at around $3,000.

      1. Pushmi-Pullyu says:

        “…more basic bikes starting at around $3,000.”

        Your definition of “basic” clearly differs rather sharply from mine.

        I had my 10-speed stolen off my front porch, despite being secured by a “Kryptonite” high-security lock. (The thief didn’t cut the lock; he cut the porch railing.) And that bike was worth less than $500. I hate to think of the kind of security (and insurance) you’d need for a bike this expensive.

        1. Nix says:

          I haven’t left a bike outside overnight since the 1980’s. In college I had a bike locker. At the commuter station I rented a bike locker, and now I keep my bikes in my garage.

          Bikes that have to be locked up in an urban environment are a completely different category of bike. They are a special case. Best to buy the oldest junk bike that you can find and paint it badly to make it look really ugly. Forget buying anything new or anything electric. It will walk.

  2. Nix says:

    This isn’t even anywhere close to the most expensive center-drive Fully for sale these days. The Haibike XDURO FullCarbon ULTIMATE runs a cool €14999,00.,3007,23476,detail.html

    1. Nix says:

      My point being that saying the majority of the price being for the BMW label is silly. Haibike doesn’t get thousands of Euro’s for their brand, e-bikes just cost a lot to build.

  3. Phr3d says:

    @Nix: so you’re saying that this would provide more comfort for my tushy than the spring seat on my Schwinn then..

    j/k if not obvious..

  4. PHEVfan says:

    If the rage in future cars is in-wheel motors, I would think that bikes could benefit from that as well. That would eliminate the conflict that center drive creates with the pivot point. Granted it puts the motor weight on the down side of the spring, but motors like this are getting lighter & more powerful.

    1. Nix says:

      There are a number of benefits of mid-drives over Hub drive for bicycles. Hub drives have actually dominated the electric bike market for years, with mid-drive only recently becoming popular.

      1) Better location for the weight. Hub motors throw the weight too far to the front or rear (depending on what kind of hub motor you use)
      2) The mid-drive can use all the gears of the bike. This improves climbing, acceleration, and top speed. Hub motors tend to bog down on steep and long climbs. Especially off-road at slow climbing speeds.
      3) Mid-drive systems do a better job of reacting to pedal stroke pressure on systems with torque sensors that vary the amount of assist to match how much effort you are putting into pedaling. hub motors can bog down, not giving full assist at times, and more assist at other times.
      4) Mid-drive tends to use less battery power than a hub drive, and get more useful assistance out of smaller electric motors. With the Tesla Roadster, they were able to ditch the 2-speed transmission by simply putting in a bigger motor and feeding it more power. That’s fine when you are talking about something as large as a car. But on a bike where the electric drive system is already about half the weight of the bicycle, just throwing more power and bigger motors at it is counter-productive.

      Again, much of this doesn’t apply if you are just riding around on level, flat streets for shorter distances. But that’s not what this bike is for.

  5. James says:

    Ted, you need to peruse YouTube, my friend. There are Craigslist beater, full-suspension Taiwanese aluminum mountain bikes with a Crystal Lite 1000W hub motors that would rock this expensive piece’s world! All for around $500.

    I have to re-post this part of the article:
    €8,345 ($9,200). That breakdown, (according to a comment on Green Car Congress) likely amounts to: E-bike: €1,000, Four-link drive arm mechanism: €1,000, BMW logo: €6,345.


    Perhaps that’s the type of cost breakdown of the i3 as well?

    1. Nix says:

      This sounds like the typical BMW M5 vs. Yugo argument. Sure, a cheap $500 dollar electric bike can get you from point A to point B. Just like a Yugo can get you from that same point A to point B.

      But pretending that a BMW M5 should have the same price as a Yugo because at the very basic level they can get you from the same point A to the same point B is silly. Same here. No, the $500 dollar cheap bike will not perform the same as this will.

  6. Heisenberght says:

    “The 2015 Heisenberg XF1 e-bike”

    I REALLY like the name of that bike 😉