The blog’s stats for the last couple of days show that my last post, about the Cannondale Dutchess concept bike for women, has generated a LOT of interest. That certainly doesn’t surprise me. Having seen quite a few student designed concept bikes over the years, I can say without hesitation that this is one of my favorites. For that reason, I wanted to find out more about the bike, and the ideas behind it, from it’s designer, Wytze van Mansum. I got quite a bit of info from Wytze, so this post will be a bit longer than usual.

Before going into some of the details, I will share his short, official explanation of the design:

“This is the Cannondale Dutchess; the result of the graduation project of Wytze van Mansum at the Delft University of Technology in assignment of high-end bicycle manufacturer Cannondale.

There is a revival of the city bicycle as a mode of transport throughout the USA in congested cities like New York. And Cannondale is eager to serve the high end of this new market.

This elegant commuter is designed with young urban women in mind, who care about their looks, health and the environment, but don’t want to be bothered with technical details or bicycle maintenance. To fill this desire of a carefree and stylish ride the design was approached as a fashion item. Although the looks of this bicycle are of a deceiving simplicity, the underlying technical details are far from that.

Dutchess refers to the typical Old Dutch bicycle, the ‘Omafiets’, but integrates its form elements in an innovative way. The rear fender acts as a structural part of the frame; it holds the carrier with a load of up to 50kg. The eye-catching arch connects the whole bicycle from handlebars to taillight both structurally and visually. At the same time it expresses the sturdiness, comfort and ease of ride of the ‘Omafiets’. What she didn’t inherit is the weight; loyal to the Cannondale philosophy the weight of the complete bicycle is kept under the 14kg by the integration of parts and functions.

The integrated transmission with the gears in the rear hub means the bicycle can be ridden in formal clothes and at any speed.

The hub brakes are completely integrated and hydraulics makes them self adjusting to compensate brake pad wear. Because the brake lines are fully integrated into the frame the brakes can double act as wheel locks. The lock in the handlebar stem locks up the oil flow and keeps the wheels locked.

The adjustable handlebars allow for different riding positions from upright to extremely sportive and they can be folded together for easy storage. They also can be used to secure the bicycle to a fixed object with the same lock that is used to lock up the wheels

High up and well visible, the bicycle rider sits on a pedestal compared to other road users. While car drivers are tucked away in metal boxes and pedestrians go up in the crowd, the Dutchess’ cyclist paddles along gracefully, displaying herself to the world. By this rational a bicycle could well be considered a fashion accessory. And this clean, maintenance free concept bike could even be sold as such.”

Pretty interesting…and you can read more about the Dutchess project (as well as see more development images) if you download Wytze’s portfolio. Several of his other bike concepts are included in the pdf, so I would definitely recommend checking it out. You probably still have some questions about the Dutchess though, so lets get into some of the features.

The frame shape is quite different, with its flowing lines and lack of seat stays, but it still comes across a clean, updated traditional bike form. That is the core of what initially appealed to me about this design. Wytze explains his idea behind the form;

“It should stand out in the shop, really something special; but when the user is riding it, the attention should be on her, not on the bike. She wants to be seen, not been stared at as if she was riding some sort of circus attraction.

I achieved this by making the form logic; normally a diamond shaped frame is the most logic form, but this is for a sports bicycle. Add the rear fender, the luggage carrier, the chainguard and the step through frame to the equation and you will see that this is a more logical form then the diamond shape. This is the reason why everybody sees it as a regular bike even though it is so different.”

The pivoting handlebars in this design allow the rider to tailor her position on the bike. Toward the middle of the pivot, the bars allow for a very upright typical “omafiets” position with good visibility for city riding. When the bars are positioned all the way forward, the riding position is much sportier (see the picture that illustrates these two positions). The system is continuously variable, so the rider can choose any position and lock it down with the handle in the middle. The fact that the handlebars also close and function as a lock is really just a byproduct of the hinged system. Wytze explains:

“There is a central locking point in the stem, it locks the handlebars (as in the video), and it locks off the flow in the hydraulic brake lines, so the wheels can be locked. Brakelines are inside the frame, stem, handlebars. Thieves need to cut into these vital parts to mess with it.

The handlebars lock is not always practical, it was mainly designed to fold together for easy storage. In the concept a cable lock was integrated inside the long arch which could be pulled out, wrapped around a fixed object and inserted in the stem, double acting as a steering tube lock.”

The modular wheel idea is another interesting element of the design. According to Wytze:

“The hubs / wheels are identical; it is transformed into the specific front or rear hub by inserting either a dynamo or gear ‘module’. This whole thing asks from you to completely forget what you know about dropouts. You have a cheap, empty shell as a hub/wheel. You slide it between the forks, insert the brake modules and the specific modules, tighten them and the wheel is all set. This is as fast as a normal set up, but you can’t take out the wheels when the brakes are engaged (hence the brake – wheel lock). Furthermore as a bike mechanic working at my LBS I have to re-lace many wheels because the gear hub wheels can’t be bought as stock part because there are so many possible combinations. Here you can order cheaper prefab (prelaced) wheels and slide in the expensive gear modules.”

This is a concept bike though, so regarding the wheels, Wytze goes on to say; “This is dreaming: this is a better standard then the current solution, but it will never happen.”

Also because it is a concept bike, the drivetrain is not completely explained. Wytze says that “it is maintenance free, it has an efficiency of 96% (compared to 98% chain efficiency). It works.” The hole in the bottom bracket is visually striking, but it had another purpose in the design; “it is the legacy of the idea to give the customer the option to fit the bike aftermarket with an electric pedal assist.

Nowadays you either buy an electric bike, or you don’t. Transforming one into the other is not simple. But here you can slide an aftermarket motor in the crank, slide the battery pack in the oversized seattube, and you have pedal assist for at least a range of 10 miles (for most commuters far enough) you can slide out the battery pack and fast charge it in half an hour. You can take out the motor and batterypack and have the advantages back of a lightweight bike.”

Wytze spent 8 months on the design and 5 months on the build, but due to time constraints, there were still quite a few details that didn’t make it into the prototype. I will let him outline some of those details for you:

– the luggage carrier is modular, you can exchange it for a basket, they love having a basket in the rear in Germany ;), or a childs seat (as the rearfender is the frame, it can be legally attached to the fender under european laws)

In the concept there are skirt guards covering a large part of the rear wheel (the arch and fender are the contours) the skirtgaurds contain envelop bags or very flat paniers as you might call them. Up front there is a basket / bag hybrid. Here in the Netherlands at the show that (lack of storage) was what bothered most people about the prototype.

– the saddle was to be a lot nicer then the stock one I used here. (see render on my site)

– there were even airless tires incorporated to really achieve that maintenance free bike I had envisioned.

– kickstand is included in the design, just not in the prototype; it is a double legged, sturdy kickstand that slides from the straight part in the rearfender near the bracket, remember the rearfender is actually a tube so it can contain the kickstand

– (though it isn’t shown in the pics) the rear fender is a hollowtube as mentioned before, there is actually a small plastic fender extension that slides out of the back, to make the fender long enough for the really rainy days.

Whew! Long post. For those of you who made it this far, I will say again that I am really impressed with this student project. If you have ever worked on a corporate sponsored project in design school, you know how many hours went into this. It is worth remembering that this design and rideable prototype was the work of one student, with input and guidance from Torgny Fjeldskaar at Cannondale (Update 11/21: Wytze had two other mentors on this project; Annemiek van Boeijen and Bruno Ninaber van Eyben).

I think Wytze did a great job. If you haven’t already, check out his website and watch the HD video of his prototype in action.