Just finished geared, fwd GX35 powered folding bike

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nwguy

Guest
A few days ago I just did the painting and final assembly on my Honda GX35 powered, front wheel drive bike. It uses a 1960s vintage Raleigh 20 folding frame. I built a flatbed cargo rack and removable sidewalls using locust wood (harder than oak), intended to allow my wife to haul two bags of groceries back from the local grocery store. The geared front wheel drive works great, and the bike works great as a normal bike with the motor off. This has been my goal with both of my motorized bikes. It uses an 18.75:1 gear reducer from David Staton (www.staton-inc.com), which is a little heavy at 8 pounds but should last forever based on the quality of construction. I've tried 18 and 22 tooth drive cogs on the gear reducer shaft and am not sure which to use in the long run. A test ride up a *very* steep and long hill allowed me to ascend at 9mph without pedaling the whole way on the 18 tooth cog. It seems to be a keeper as it rides very well and should be really functional with the cargo box.

-Jim
http://www.outsideconnection.com/gallant
 

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Dennis Becraft

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How does it compare to your GX31 bike? Seems like this one will perform a little better. Do you miss the suspension? I'd really like to know your mpg figures. They should be very high. Probably better than 250. I'd like to see you build a streamliner and regear to take advantage of the reduced wind resistance. Sam Whittingham got over 80 mph on pedal power alone that way. I'll bet you could get phenomenal performance and fuel economy with a fully enclosed fairing. I'm amazed I haven't seen anyone combining HPV type streamliners & multispeed small engines. Don't forget to add your little trademark orange mudflap.
 
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imperfectionst

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I would think full streamlining on a two-wheeler would be difficult to control in real world conditions, with trucks and side wind. So you need a trike, which gets heavy. It's a neat idea though.
 
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nwguy

Guest
The performance between the GX31 powered recumbent and this FWD upright are pretty close. With what limited riding I've done on the upright (weather's wet and cold lately), the recumbent seems to beat the upright for top end speed. I think that's due to a combination of better aerodynamics and a slightly higher high-gear. They say 90% of resistance on a bicycle above 20mph is wind resistance, so the laid back position of the recumbent is a huge speed advantage. When I commuted on it, simply folding one arm in towards my body and pointing my toes forward would boost my speed by one or two mph. As for gas mileage, like I mentioned in another post, I commuted a month and a half on it once, nine miles each way and didn't use up the gallon of gas I had in my one gallon tank. Yes, I do miss the suspension. It was almost sinful it was so comfy. But the Cloud 9 seat on the upright is pretty great.

The upright seems to have more raw power though with the slightly bigger engine, but less top end speed. I built it for climbing a killer hill home with groceries, and will probably switch back to the 22 tooth drive cog from the 18 tooth cog, forcing my wife to pedal a bit going up hills so I can enjoy higher speeds.

When test riding it up the killer hill, the pavement was wet, and I purposely rode off into the sandy shoulder to see what happens up a very steep hill with FWD on wet sandy pavement. Yes, the front wheel slipped, especially when I leaned backwards. Leaning forwards reduced the slippage. Riding back out onto the wet pavement stopped the slipping altogether. This was a *really* steep hill, probably greater than 10% incline.

I'm surprised more people in this forum don't try FWD solutions. They solve a lot of problems. The hardest thing about it was building the fork. Am wondering if there'd be any interest in people purchasing a replacement "front end" (fork, front wheel, derailleur, motor and reducer) as a kit. You could pretty easily convert any bike to a geared, motored bike while retaining the pedal performance of a decent bicycle

As for motorizing a faired bicycle, yes performance and economy would be phenomenal, but crosswinds would be dangerous, and mixing with "real" motorized vehicles at the speeds you'd attain would be too.
 
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Dennis Becraft

Guest
Jim's geared, FWD, GX35 powered, folding, NAKED bike

They say 90% of resistance on a bicycle above 20mph is wind resistance, so the laid back position of the recumbent is a huge speed advantage. When I commuted on it, simply folding one arm in towards my body and pointing my toes forward would boost my speed by one or two mph.

As for motorizing a faired bicycle, yes performance and economy would be phenomenal, but crosswinds would be dangerous, and mixing with "real" motorized vehicles at the speeds you'd attain would be too.
I guess I should not have recommended a "fully enclosed" fairing. There is a great deal of work that has been done with practical streamliners that are not fully enclosed, are easier to get in & out of and are not significantly vulnerable to crosswinds, primarily by having rounded vs. slab sides, truncated tail sections, vents etc. Since you've noticed improvements with minor posture changes, I'm sure you could design for greater aerodynamics that wouldn't compromise safety. I can mix with traffic using a sail on my recumbent. I use it PRIMARILY in crosswinds! http://www.youtube.com/watch?v=xKmZRoK7CRw
There have been coast-to-coast crossings by 2 wheeled recumbents with "practical" full fairings. The Lightning F-40 did it in 5 days & 1 hr. in 1989 (L.A. to N.Y., 2,910 mi.). I very firmly believe there is much neglected potential here. Fairings don't have to be used to go too fast for safety in traffic. They can be used for weather protection and economy. There are very small engines that could get decent performance in a streamlined vehicle with a multispeed transmission like yours. Weedeaters start at 18cc. There are lots of 25cc engines. Some of us like myself live in flatlands. Some use our bikes for very long trips on low-traffic roads where it would be safe to go much faster than we do now. It just seems natural for us to try to get every advantage we can. Somebody will be doing it soon. Why not one of us? Start Googling recumbent fairings, you'll be convinced when you learn how huge a difference they make. I don't want to stay on my soapbox too long in your thread Jim, I just think someone with your skills could easily make a whole new class of machine. And yes a front end "kit' like you describe is an EXCELLENT idea. Better than anything I've seen on the market. I wish I'd thought of it. Here's my rudimentary version: http://www.youtube.com/watch?v=5L8QEYN5w9U
 
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