Just finished geared, fwd GX35 powered folding bike

Discussion in 'Photos & Bicycle Builds' started by nwguy, Dec 30, 2007.

  1. nwguy

    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.


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  2. locoWelder

    locoWelder Guest

  3. 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.
  4. 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.
  5. MtnGoat

    MtnGoat Guest

    Wow nwguy, that 5 speeds on the front is wild! Congratulations.
  6. Dockspa1

    Dockspa1 Guest

    Looks awsome Nwguy! That is the stationwagon of MBc's. :D:smile:
  7. iRide Customs

    iRide Customs Member

    Sweet ride! I bet the wifey is grinning ear to ear every time she runs errands.
  8. nwguy

    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.
  9. dbigkahunna

    dbigkahunna Guest

    That is a great set up. I would be interested in a set of plans.
  10. Jim's geared, FWD, GX35 powered, folding, NAKED bike

    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
  11. Jim H

    Jim H Guest

    Dang!!! That's really, really, really nice! I want one, now!
  12. Bean Oil

    Bean Oil Guest

    Sounds great!

    Just doublechecking something: when decelerating, the freewheeled cogs do not allow any engine braking, correct?

    Other than that, does the shift technique involve a slight de-throttle?

    Thanks for your reply.

  13. nwguy

    nwguy Guest

    Decelerating and de-throttling

    The driving cog mounted on the Staton gear reducer box is just a 3-prong coaster brake hub style cog. The driven cog is the 5-sprocket freewheel mounted on the front wheel. When the engine's off, the front chain and freewheel stay still while the front wheel spins. So the front wheel makes the "ticky ticky ticky" sound of a freewheel spinning while you ride with the motor off. Same thing when you're decelerating, although you can't hear the "ticky" sound over the engine. There's no engine breaking as it's not a "fixed" gear.

    No need to let off the throttle while upshifting to smaller/higher-gear cogs, but it helps when downshifting to bigger/lower-gear cogs.


  14. beast775

    beast775 Guest

    great build

    theres somethin about those foldups and motors that i like,good build lots of work,great front rack for staton box wow.:shock:
  15. Egor

    Egor Guest

    I built a folding bike a few years ago. I think yours is a first rate looking job. Did you lace the hub into the front wheel? I never got a clutch on mine just direct drive, I was going to install a compression release and then just pedal off and release, Zoom. Thanks for making me think, I have a Honda GX35, (keep that oil changed). Have fun Dave
    PS: I am sitting here in Ca. and I keep hearing that train sound in the wind. It is tearing up the awning in the back yard.

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  16. Dockspa1

    Dockspa1 Guest

    Not to change the subject too much, Egore, it looks like on the news you guys got ripped apart with the wind and then in the mountains, 10 ft. of snow wow!
    Now to put it back on track.
    How do you think those fold-ups would hold up riding in that? Fold up? Ha Ha
  17. I need to take a nap now. All that and it fits in your trunk. My brain is overflowing.
    That is the colest thing I seen today.
  18. Jim H

    Jim H Guest

    My little sister got a folding bicycle for christmas from Sears in 1967; 20" wheels and a heavy duty frame and rack. We used to ride three at a time...sure would like to find that old model...
  19. Sianelle

    Sianelle Guest

    The detail work on your Raleigh 20 is beautiful. I agree about the front wheel drive, - it's a wonder it isn't used more often than it is.

    Hum...... as it happens I've got a Raleigh 20 underneath my work bench....... :smile:
  20. nwguy

    nwguy Guest