Category Archives: Recumbent Bicycles and Velomobiles

Posts about recumbent bicycles and velomobiles.

What’s underneath?

People ask me what the Leitra velomobile I ride is like under the fairing. Here are two pictures of the frame that I took last time I was doing maintenance on the bike and had all the fairing pieces and seat removed.

Leitra frame front

Leitra Frame front

From the front, you can see the two piece, carbon fiber leaf springs for the front two wheels. The “Y” shaped bit at the very front is where the front fairing attaches and pivots for entry and exit. The seat snaps into the frame just ahead of the rear wheel. In the center of the back of the bike is the rear wheel which sits inside a wraparound fender that keeps water, snow and dirt out of the seating area.

Leitra frame rear 3/4

Leitra frame rear 3/4

From the rear, you can see the Bionx electric motor assist. It consists of the linear motor hub in the middle of the rear wheel and the battery mounted under the left arm rest. The cargo area of the fairing sits above the rear wheel on the rack-like extension. The “V” shaped parts in the middle of the rack and two small strips on either side of the rear wheel are carbon fiber leaf springs for the rear wheel.

The frame is hard to pickup and put on a work stand, so I usually just hang it from my work stand with a loop of rope as shown. This lets me turn the rear wheel and adjust the derailer and lube the chain.

Sikorsky Prize falls!

One of the things got me into riding human powered vehicles was watching a NOVA episode on the Kremer prize for human powered flight. One of the MIT professors involved in that effort was riding a recumbent bike in several of the videos, something I had never seen at the time, and I fell in love with the idea.

Today, the Sikorsky Prize for a human powered helicopter has been won by a Canadian startup company Aerovelo. You can read about it here. Congratulations!

Another snowy ride home

Seems like this winter has a pattern of snowfalls during the day. Makes it tricky to judge if the snowfall will be too deep for me to ride home. I’m not exactly sure what my limit is, in part because the difficulty varies with the consistency of the snow, but more than an inch gets worrisome.

Here’s my Leitra tucked in to the garage after this evening’s ride home from work.

Leitra in garage

Leitra in garage

The Rest of the Fall Leitra Maintenance

I’m cleaning up my electronic files and realized I had a few pictures from my other fall Leitra maintenance that I had not posted, along with some notes on fixing a shifting problem with my SRAM DualDrive 3 speed hub plus de-railer.

To start with, it’s easiest to strip the fairing off of the Leitra to work on the drive train. It’s buried inside all that fiberglass to help protect it from the weather and keep it clean. The fairing is four parts. The nose and window section that tilts up for access, the upper tail box and side curtains and a two part lower tail box that provides some storage that is accessible from inside while you are riding. Here are pictures of the Leitra with the nose and tail box removed.

Leitra w/o nose & tailbox

Leitra w/o nose & tailbox

Leitra w/o nose & tailbox, another angle

Leitra w/o nose & tailbox, another angle

The major item on my repair list was to figure out why the 3 speed hub portion of the DualDrive was “stuck” in under-drive and would not shift into pass-thru or over-drive. The DualDrive has a “click box” that handles the 90 degree turn from the shifting mechanism inside the hub to the cable that runs to the hand grip shifter. Here’s a picture of it mounted on the Leitra. You can see that rear wheel sits inside a full coverage fender that extends down to a lip that protects the chain and de-railer arm from spray coming off the rear tire. The “click box” is circled in red.

DualDrive on Leitra

DualDrive on Leitra

The “click box” can be removed by setting the shifter in “low” or “under-drive” and pushing the black button on the box. This reveals the long bolt that goes into the shifter mechanism. This was surprisingly loose, which made me think I had found the problem.

A little Google searching later, I found that, indeed, that bolt needed to be firmly tightened for the hub to shift properly. I tightened the bolt up and then adjusted the shifter. The “click box” makes this easy with a little alignment window and a yellow indicator. The arrow in this next picture points out the alignment window. The yellow indicator should be in the yellow outlined box when set correctly.

Clickbox window

Clickbox alignment window

Once I had the shifter aligned, I had all my gears back!

I use the SRAM DualDrive in two ways when I ride.

On longer rides, I use the 3 speed hub like you would use the pedal chain rings, for large adjustments in the gear range. I use the de-railer for smaller adjustments.

But in traffic on my work commute, the 3 speed hub’s ability to shift while not in motion is a big asset. I tend to simply shift the 3 speed hub, ignoring the de-railer when going stoplight to stoplight because I can quickly drop down to low gear when stopped.

Needless to say, I’m glad to have the hub back in working order!

New Taillight

I’ve started preparing the Leitra for this coming winter. One thing I’ve wanted to do for a while was replace the low-powered taillight. The original light had 2 LEDs and wasn’t as bring as I would like. After a bit of searching around, I found a 5 LED light that uses higher brightness LEDs and offers several blinking patterns. Most importantly, it came with a mounting bracket that fit in the narrow space in the tail box lid. Here’s what it looks like from inside and outside.

Taillight from inside the tail box.

Taillight from inside the tail box.


New taillight from the outside.

New taillight from the outside.


New taillight from outside and above.

New taillight from outside and above.

Don’t know my own strength

On the way into work Wednesday morning, I pulled up to cross State Street, just a block from my office in Young Graduate House, a high rise dorm that’s been converted to office space, and as I pushed off I felt the seat back on V-Rex sag and something poked me in the side. Uh, oh. On brief inspection, I could see the seat was moving free of the cross member that mounts it to the sprint braces. WIthout that support, the seat (and therefore the bike) was out of action. Thankfully our van was empty and my wife graciously came by at lunch and helped me take the V-Rex back home. Today, I got down to figuring out what happened and fixing it.

Rans SeatThe Rans seat was one of the first really popular recumbent seats, appearing not only on Rans products, like my V-Rex, but also on other companies bikes as well. It is a large foam covered triangular base, with a cross braced, mesh fabric covered frame for a back. It attaches to the bike at the seat bottom and to sprint braces which usually go back to the rear triangle. The attachment points are marked by arrows in the picture on the right.

The upper mount point is part of a cross brace between the two vertical tubes that make up the seat back. The pop rivets that hold that in place had failed and cross piece had come free.

Cross Piece

After drilling out the failed pop rivets, and banging out the slight bend that one of the sides of the cross piece has acquired thanks to that last push off, I was able to pop rivet the piece back where it belonged. Then I put the seat back on the V-Rex and adjusted the tilt and distance from the pedals to fit myself.

I like the sliding seat back arrangement on the V-Rex better than a sliding pedal tube for several reasons. First, it’s simple to adjust. On the V-Rex the slide is help in place by a quick release skewer. Second, there’s no chain adjustment that needs to be performed whenever the seat is moved.

I’m looking forward to being back on the V-Rex come Monday’s ride to work.

Third Time’s the Charm

I wrote in a previous blog about commuting to work by velomobile. I found writing just about the Leitra a bit confining and wanted a broader scope. 🙂 So, here it is. This blog will be about bike commuting, managing a technical team, photography and other random things. It’s about trips that take some effort and by expending the effort the traveler learns and grows.
Along the way, I upgraded my server to OS X Lion and lost the nice Apple provided Blog tools. 🙁 So, I took the advice of my friend Hal Stern and made the jump to WordPress. My third blog platform. It’s pretty slick. So I imported most of my previous blog posts into this one. I think this will carry me for a while.