Direct drive recumbent.

[Andrew 1973]

7kg = ~15.4lbs

Despite the weight, that is a very clever design. I'd certainly like to give it a try just to see how it compares to the MBB configuration that I am used to.

Regarding the frame...broken carbon hockey sticks? Who would have ever thought?

 

[Eric Winn]

Instagram link

Instagram link (opens in new window):

http://instagram.com/hubcycle

This thing is really cool but that hub assembly looks enormous in the video over on Instagram...

Googling hubcycle is not very helpful - lot of stuff out there already using that name...

-Eric

 

[bladderhead]

Is the MC2, in speed mode, a

Is the MC2, in speed mode, a belly-bike?

Pinion is squarely aimed at Rohloff's market share. On a diamond-frame, Pinion is better weight dist, but on a Cruzbike, is Forkflop City.

 

[andrei.petrov.90]

Looks great, Joakim

Please share more ride videos

 

[Wannabe]

Way cool

..... I can see it now. A vendetta Hub Warp Factor two wheel conveyance!!!

 

[Óscar Morales Vivó]

Signed up just to mention that I'm happy to have found that someone more mechanically inclined than I could test if this concept would work. I'd love to have one of these as a commuter myself.

Feel free to post plans and stuff, I'll eventually find out someone handy who has a workshop and owes me a favor ;o)

Only question I can think of: could a Rohloff be adapted to direct crank use? If so it may make for a less ginormous front wheel hub assembly (not sure how many gears would be useable either).

 

[hamishbarker]

7kg for the front wheel seems huge, but think about it like this:
in addition to the normal function as a wheel, hub and tire, the big front wheel replaces the following:
- bottom bracket (2-300gm?)
-chain (500gm?)
-derailleurs (front and rear) (200gm)
- bottom
- one shifter (since only one shift cable needed, or is it like a rolhoff with twin cables making a loop? anyway, still only one shifter (save 100gm?)
- multiple chainrings (300gm?)
- cassette (300gm?)
summing these replaced bits: 2.2kg?

Still seems to be a lot of excess weight. I guess there is some beefy metal in the flanges which the forks attach to , and also the flanges which the spokes attach to are much much bigger than usual. Not to mention the BIG cross sectional area of the hub. With the front end being so heavy, perhaps susceptibility to crosswind in case of putting full disc covers on it would not be as bad as on other bikes.

It's certainly appealing to remove so much stuff but either pinon gearboxes are over engineered and too heavy, or the gear ratio/ weight of a conventional drivetrain are just very hard to beat. I guess there have been many decades of development of the latter to get the weight down.

 

[MrSteve]

This is an old thread!
The broken hockey stick bike still looks like it's a comfortable, relatively fast commuter.
Here is a thought...:
That big hub would be useful as a windbreak if it were used as the FRD transmission in a low racer.
The bike would be very long and it would not turn very well at all, but it might work as a fast, comfortable, reliable randonneur.

 

[Martinius Berg]

Hello Joakim

Martinius here from Norway. I have the Nuvinci Harmony N360 hub installed combined with the Sclumpf SD on my Challenge Chamsin . As far as i can understand the Nuvinci N 360 design and tech. it would not be adaptable with your direct wheel drive.

It would be fun seeing you bicycling fast on this prototype

Sinc. Martinus Berg

 

[Jeremy Garnet]

Response to some of the discussions about my paper (Garnet paper):

I feel a need to respond to some of the discussion about my paper in this forum, particularly the critique that the paper is based on a misunderstanding of bicycle ergonomics. I think this perception stems merely from a misinterpretation of the scope of the paper.

I agree with John Tolhurst that upper body involvement in the control of a bike is an important aspect of riding, and vital to the ergonomics of any bike. This is one of the reasons I believe that MBB bikes are a compelling design. Far from being a disadvantage, there can be an athletic benefit to resisting some pedal forces with the upper body. In the paper, I acknowledge this by stating: “the involvement of the arms and upper body in the pedaling process is not unpleasant but brings a certain athletic appeal to the riding” (end of page 2).

However, it can be too much, which was my experience from riding my direct-drive recumbent, so I sought to find ways of reducing it by analyzing the impact of head angle on pedal force feedback – hence the paper.

One of the interesting things that came from the study was the positive impact of the outward lateral component of the applied pedal force. This force component decreases the pedal force feedback, but does this to a greater degree when the pedals are located further forward from the steering axis (due to better mechanical advantage relative to the steering axis). Therefore these forces have a much greater beneficial effect on a chain-driven MBB bike than on a direct-drive MBB bike. I believe this is the reason that excessive pedal force feedback was an issue for me, but is not a problem with the Cruzbike.

So my paper is not in any way a critique of the Cruzbike’s geometry. Rather the reverse – my research supports conventional frame geometry for chain-driven MBB bikes (see figure 20 of the paper). The Cruzbike is an excellent design and has the correct frame geometry. For chain-driven MBB bikes, there is absolutely no need to incline the head angle, or to do any of the things I suggest in my paper. These design challenges, and my recommendations, are exclusive to direct-drive, where the pedal crank is closer to the steering axis.

I trust this answers some of the misgivings surrounding my paper.

Jeremy Garnet

 

[Cruzbiker]

How did you make the handlebar? I like that angle for the hands and plenty of space for lights, cycle computer etc.

 

[Roger Underhill]

Kervelo have produced a fwd direct drive with pinion mounted in the wheel. Their website seems to have changed a lot and the range of bikes seems very different to the last time I looked. Here’s a link. http://www.kervelo.com/ No pinion in sight right now so I’m not sure what’s going on there

 

[Rampa]

Looks all there to me.

Suspended and unsuspended bikes.
Gearbox for frame mount or hub/crank-gearbox.
7 or 12 speeds.
Much more refined designs now.

My only concern is having the cranks so low. I'm used to having them at seat height, or a bit higher.

 

[Roger Underhill]

That goes with the territory Bigger wheels is the only way to fix that but I think it’s all relative to the seat angle so from what I’ve seen it would probably be ok. I think the carbon version was lower to the ground in any case. My concern then was heel clearance for my size 13 feet! They told me it wasn’t an issue though