Sunday, January 27, 2013

Finished bike

An overview of the steps...

The original design

The foam plug

The final DIYcarbon fiber handcyle with hardware 

Over the last 3 weeks I have added the chain guard and leg holders to the handcycle.  You will also see a round hole in the carbon fiber just behind the back support and below the neck support.  The hole gives access to the interior of the handcycle in order to store two 100 oz. hydration pack, spare tire, and tools.  also, I will be adding built-in rear red lights -- one on each side of the bike.
Leg holders and chain guard

Some other views:

Side View

Tool storage, Embedded cables

The next steps is to test the bike on the road... stay tuned...

Monday, January 7, 2013

Base & Fork

The base is nearly complete.  There is still some work to finish on the neck of the base as well on the inside of the wheel wells.  I coupled the base and the fork with the headset bearings and steerer tube.  I probably should have given a bit more space (another 1 or 2 mm) between the fork and base to accommodate the turning of the fork.  Everything fits together though.  

When I finish it, I will lock in the steerer tube into place with cam-type of headset cap on both the top and bottom of the steerer tube.  I designed fork to be able to be easily remove and replace it in case I travel by air. It only takes a few minutes to decouple and re-couple the fork to the base.  

Here are the pictures:

Top View


Top Front

Wednesday, January 2, 2013

Finally -- Speed Comparison Between Two and Three-Wheeled Handcycle

My inclination that a two-wheeled handcycle is faster than a three-wheeled handcycle may have some ammunition.  The site -- -- allows one to compare the aerodynamic efficiency of various bikes and riders in many configurations. The bike types include a three-wheeled handcycle.  (BTW, this is only available on the German edition and not the English one-- but math is math no matter the language.)

One edition of the calculator mentions the use of SRM's PowerMeter for verification of the aerodynamic efficiency results.

The difference between a two-wheeled low-rider recumbent and a three-wheeled handcyle is actually greater than I envisioned.  If indeed the two-wheeled handcycle works, I may be looking at  a 5 mph improvement under race (and perfect) conditions.

As I had mentioned in an earlier post, I thought I was pushing out about 200 watts average (hey, I am old and it is only arms!) over about 20+ miles at near race pace.  The calculator output below pretty much confirms that. Considering that I had actually raced 26.2 miles at 19.1 mph with no drafting, a large hill and about 40 turns/curves -- many of which required braking -- I would expect that the the calculator -- with the 3-wheeled handcycle bike type selected --would predict a slightly faster pace since the calculator is using 0 slope. It did indeed (about 0.7 mph faster @ 19.8 mph):

The calculator with a 2-wheeled recumbent low-racer (all else equal) calculates 24.3 mph:

There you have it!  A 8.3 kph difference in bike types equates to as 5 mph increase in speed at race pace.  For my longer workouts (90 - 120 miles) I can expect  (well, "hope for") a 4.2 mph improvement.  Of course this is under perfect conditions that never exist!