DF vs DFXL Size

While I’ve got both a DF and a DFXL in my garage, I thought I’d post some photos that show the size difference between the two models for reference.

Here are the dimensions.

Check out how Daniel Fenn derived the pattern (buck) for the DFXL from an expanded DF. Notice how he avoided expanding the wheel wells, derailleur hatch and front cover to keep the changes simple… Very clever.

The DF (blue) and the DFXL (red) currently residing in my garage. BTW… one of these will be for sale after a brief evaluation period,

Good Bye to the Catrike 700 and Hello to DF 141

I’m once again a 3 velomobile owner. I’ve just completed a trade of the black Catrike 700 plus cash for a crashed standard DF velomobile. DF 141 had been involved in a crash about a year ago when it ran into the side of a car that turned into its path. The owner had repaired the resulting cracks and ridden it for the last year. The repairs were structurally sound but not pretty.

So why would I do this deal? Ever since I managed to squeeze into the tiny Milan SL, I wondered if I could downsize from my DFXL to a standard DF. A standard DF would have a smaller frontal area which could potentially be faster. My 700 spent most of its time hanging in the garage so it was time for it to go. The plan is to spiff DF 141 and see if I can comfortably ride it. If so, I’ll sell my DFXL. If it’s not comfortable, I’ll sell it and keep my DFXL

Carbent Raven (Sold)

I’m pricing this Carbent Raven for a quick sale. I am the second owner of this bike. It has a fairly large frame. I would guess that it would fit a rider with 43″ to 47″ X-seam. It weighs 21 lbs with pedals. It shows that it has some miles on it but is in good mechanical and cosmetic shape. There is one exception – the carbon fiber seat has been patched on the face surface which is covered by the seat foam. (See the photo below). The seat seems structurally sounds but that hidden patch is not pretty. This bike is ready to ride today.

sold!

  • Some Details
    • FSA double crank with Q-Rings
    • Terracycle Idlers
    • SRAM chain with little elongation
    • Mavic 700c wheels and hubs
    • Bacchetta long handlebars
    • New foam seat pad
    • X-Eyed front brake, Bacchetta (?) rear brake
    • Avid brake levers
    • Shimano SPD pedals


Another Bike!

Only days after I picked up the Carbent, I noticed a posting in Craig’s List for a Bacchetta Carbon Aero for $1000. It looked to be in near new condition. I had to check it out. So, I made the trip up to San Luis Obispo and bought it on the spot. It has some pretty high end components like a carbon fiber crank, Q-Rings and a carbon fiber seat. It is pristine.

I’ve ridden both of my high racers and have decided that the Carbon Aero is staying and the Carbent will be put up for sale soon.

Getting Back On A Bicycle

It’s been a year or two since I’ve owned a recumbent bike. Recently my friend, Gregory, bought a used Carbent high racer. We get together from time to time to ride trikes or my velomobiles so I thought it would be fun to get a similar bike so that we’d have another option on our rides.

I began looking for used Bacchettas and Carbents. I even considered buying a new Schlitter Freestyle. But, since I don’t anticipate riding a bike very often, I decided to spend as little as possible. I was able to pick up this used Carbent Raven on eBay for a very low price. Carbents are built to fit the buyer. Boom length and seat recline are not very adjustable. So, I hope that I won’t need to do any surgery on this bike. I’m sure that I’ll need to refresh some parts before I take it on the road.

Update: I picked up the Carbent and it was in much better shape than I had expected. It fits me well. It will need a new chain and some cleaning but that’s about it.

Front Wheel Fairings for the DFXL

As part of the effort to help PeterB’s Battle Mountain run, we’ve been working one some front wheel fairings. These are added to the bottom of the factory pants to shield the exposed lower wheel. This has been a real challenge. The shape has to enclose the front wheels yet being wide enough to allow the wheels to travel through the steering arc. Also coming up with a shape that allows mounting to the curving bottom of the pants has been tricky. At this point, I’ve gone through three iterations of shapes. Each iteration involves building a plug, mold and part. So far, each shape has been symmetrical side to side so that I can use a single mold and trim the resulting parts to fit right or left. Before showing the evolution of shapes, here’s a photo of the latest iteration, painted and mounted on my DFXL.

The first shape that I came up with is a long teardrop shape with curved sides. The problem with this shape was that in order to open the tire slots wide enough to allow the maximum steering angle, the slots opened into the vertical part of the sides (due to the curve of the sides).

This lead to a second shape with vertical sides. This allowed plenty of room for cutting the tire slots in the bottom without the slots going up the sides. But the fairings looked massive when attached to the pants.

The third shape was based on the second but was shorter and with reduced volume.

So this is where we are right now. This 3rd iteration is smaller and there is enough room to cut the tire slots. It’s mounted with the use of magnets and tape as shown below.

However, I’m still not happy with the shape. The front seems too blunt and the tail should be elongated to make it more teardrop shaped. If I can muster the energy, I think that I’m going to modify the first shape to overcome its flaws. In the photo below, you can see the current shape in red and the first shape in white.

Oh and by the way… We have not tested the idea of adding fairings to the pants. For all we know, these things could add more drag than they’re worth. We’ll do some roll-down tests to make that determination.

“Screwless” Access Panel for the DFXL

There’s a little project for the DFXL that’s been on the back burner for a while. The front access panel on the DF is held in place by ten flat head m4 screws. I seldom need to remove that panel but when I do, it’s a bit of a nuisance. This can be particularly bothersome while out on a ride. In addition, I have to say that I find that the visible screw heads detract from the look of the DF. So this has lead to my “Screwless” access panel. There were 3 goals for the panel.

  • Be quicker to remove and re-install.
  • Give the DF a cleaner look.
  • Require no modifications to the DF body itself. The mounting system must be confined to only the panel.

Here’s the first iteration of the screwless panel. This was produced from my mold, followed by a little body work to remove the stock countersunk screw holes.

I’ve found that the addition of the NACA duct on my previous panels really made a difference when riding on warmer days. Here’s the screwless panel with a NACA duct added.

To mount the panel, I came up with a simple system of flexible tabs attached to the panel that would catch under the lip of the body. The tabs are attached to the panel using six carbon fiber slotted anchors that are epoxied to the panel.

Here’s the underside of the panel with the NACA duct and tabs installed. Different materials were used for the tabs in different locations to provide the right flexibility to allow easy installation but with a firm mount. The tabs slide into the carbon fiber slotted anchors made with a male/female squish mold. All of the tabs except the 2 rear tabs stay with the panel during installation. They’re just tucked in after the panel is in place. The 2 rear tabs are inserted after the panel is in place. It takes a few seconds to install or remove the panel. No modifications to the DF body are required.

This is the 3D printed squish mold used to produce the carbon fiber slotted anchors.

Full view of the DFXL with ducted, srcrewless access panel.