Monday, May 12, 2014

Add two DIY Carbon Disc Wheels

Finished Wheels with Carbon Fiber Covering

If you have read this blog previously, you probably get a sense that I hate to spend good money on expensive frames and parts if I can figure out a way to build those myself for a much more reasonable price. The one area for which I may be able to gain the greatest benefit (speed) for the least amount of cash, is to build disc wheels.

My initial search of what others have done relative to DIY disc wheels was to find that many had bought sheets of plastic, cut a circle from it, slice the circle from its center to its perimeter, and make a "cone" or disc that fits from the hub, to the spokes and to the rim.  Then the do-it-yourselfer would then glue, tape, and/or mechanically fasten the plastic disc in place relative to the hub, spokes and rim.

Some studies even propose that DIY disc wheel covers perform equal to the expensive carbon fiber disc wheels.

As I was searching the subject, I found that many disc wheels actually contain spokes.  Well my existing wheels contain spokes.  And those wheels do not have rim brakes...

After ordering 24"x24" - 3/32" ABS plastic sheets, I retrieved the delivered box from the front door, only to find that the box of plastic was actually pretty heavy.  I do not need more weight for the handcycle! So I decided to use a a similar technique as mentioned above, but with a single layer of carbon-fiber substituted for the ABS plastic.  This would reduce the weight considerably.

The process of building the wheels was to use one layer of carbon fiber for each disc (one disc per side of each wheel).  I laid out the carbon fiber fabric on the ABS plastic I had bought (with the intention of building wheel covers). This ABS plastic was cut to a diameter that slightly larger than the wheel rim. I then applied the West System 206 epoxy to the carbon fiber fabric. The side of the carbon fiber fabric on the ABS-side was to be the finished surface.  After the epoxy cured, I was able to remove the carbon fiber from the ABS plastic.  It did not stick (to speak of). This gave me a fairly clean, flat and finished piece of single-layer carbon fiber.

Each  carbon fiber disc, after I sliced it from the center out and cut the hole for the hub, was glued to the rim. Of course the hub and spokes were in place on the rim.  The discs were oversized initially  There is an overlap now where the disc was sliced from its center outward as it is fitted to the hub outward to the rim. This is to accommodate the dishing of the wheel.  I applied epoxy to the overlapped area of the disc.

After the epoxy attaching the carbon fiber disc to the rim cured, the extra carbon fiber that extended past the edge of the rim was removed with a dremel tool.  

The first 30 miles on the DIY Carbon Fiber Wheel Covers went quite well.  I was surprised that the wheels were not "louder."  In the past, I have often heard cyclists with carbon-fiber wheels approaching me long before I was passed due to the vibrations/drum effect.  I expected the same from these.  But my expectations were not quite met.

Thursday, May 1, 2014

After 150 miles...

Delta-handcycle after the first 150 miles
My thoughts after 150 miles...

1 -- The handcycle feels pretty good.  That is, it fits like a glove -- or more precisely -- a recliner fit to my body.  As an example, when the weather is bad or I start a late workout I put the handcycle on the rollers, indoor, and throw a couple of  movies on the "big screen", I often do not get off the bike even after I finish the workout. Instead, I continue to lay on the bike to finish the films.  Hell, it's more comfortable than a chair.

My recliner for movies...

2 -- The disc brake is fantastic.  I will never ride a handcycle without a disc brake again.  On my next bike, I will design two of them into it.

3 -- The bike is LOW to the ground.  That makes it nice for getting off the bike.  I just slide over to the garage floor.

 4 -- Faster? I don't yet know if the bike is faster as compared to my Force-G or not.  My right shoulder is 4-5 months past the surgery.  The shoulder is getting stronger quickly but I cannot push particularly hard.  Though on a couple of small downhill areas of my "nightly" ride, I would hit 26 mph max (after a climb). In comparison, without pushing, I did hit 27 mph with this bike.  So, this bike is at least as fast as my old one.  BTW, I had modified the Force-G such that I was laying pretty flat on it as well.  I am carrying about 7 extra pounds on the bike (about equally divided between the transmission and the carbon fiber). As well, after many months of little activity I have gained 7 pounds of fat.

5 -- I had to rebuild the handles in order that my hands would be more comfortable (the other handles were too small). Additionally, I wanted the right handle to have the twist shifter built right into it.  The design works out very well!  It is comfortable for short rides.  The real test will come on the 200K and longer rides.  That is when the hands cramp and shifting becomes more difficult.

Right-side handle with twist shifter built in