Gravity racer - Calling all daredevils!

Discussion in 'BUILD CHALLENGES' started by breakurnees, Jun 17, 2011.

  1. breakurnees

    breakurnees

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    Careful out there guys. I should be getting leathers and a helmet this week, but I was feeling bulletproof and ran my bike down the driveway with shorts on. Now I am missing some skin on one of my knees.
  2. Three-Wire

    Three-Wire

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    I was in Creede, Colorado over the weekend and spotted this:

    [​IMG]

    A little different than what we're building, but still interesting.
  3. Philphine

    Philphine

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    [​IMG]

    [​IMG]

    truthfully, i picked this up for a compleatly different type of bike, but it could make a nice downhiller if you could keep the drivetrain to pedal back up.
  4. Three-Wire

    Three-Wire

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    Did a little work tonight... It's almost ready to run, but lots of little things still to do. Like rear brakes... And different tires... And truing the wheels and brake discs... And figuring out the final solution for the foot pegs... And adding balast... And maybe some paint and cleanup?

    [​IMG]

    It certainly could benefit from a fairing of some sort. If I can find the time next week, I've got some relatively easy ideas for a quick and temporary fairing.

    [​IMG]

    With me on it, the proportions look more appropriate but still I think a fairing would do wonders for the overall appearance.

    I may get a few hours to mess with it on Sunday - if I can get the brakes and tires done (and scrounge up the right P.P.E.) I'm gonna try to go test run the thing down the local hill!
  5. Philphine

    Philphine

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    well, it looks fast, anyway.

    probaly no aerodynamic benefit to it, but i added a bit of lexan to the numberplate from the x-games bike for my second bike

    [​IMG]

    i also used a squeeze clamp thing and propane torch to give it a little more curvature, maybe too much

    i have a second numberplate i may put on my real g-bike attempt (assuming i ever get more speed/riding in on it), but i want to learn more about how to shape it to maybe get some genuine results from it.
  6. Philphine

    Philphine

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    today's the day ain't it? is it over? last minute entries? extension?
  7. Three-Wire

    Three-Wire

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    I didn't get to run yesterday, so I'm out unless there is an extension to next week... It was fun, and it will run next weekend!
  8. breakurnees

    breakurnees

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    I'm all in favor of an extention, since no one has shown any proof of a run yet. I meant to today but worked 14 hours instead. How long should we go?
  9. Three-Wire

    Three-Wire

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    End of the month? End of the year? All I need to get a run and technically finish is through Sunday, but it'll take me at least through the end of the month to get the fiberglass and appearance work finished. 8)
  10. breakurnees

    breakurnees

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    Lets make it Halloween. That should be more than enough time.
  11. S.I.N. CYCLES

    S.I.N. CYCLES

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    We got our bike rideable and took it to the Fall Maryhill Freeride in Washington. I'll have some video of it soon.
  12. Three-Wire

    Three-Wire

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    Can't wait to see it! I've got the day off, so I'm working out the last kinks... Front AND rear bakes are functional now, wheels and temporary protective coating are next. :D
  13. S.I.N. CYCLES

    S.I.N. CYCLES

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    Our friend took this footage and made this video. Here you'll see our newest complete scratch build gbike (s2) and me crashing the bike in the instructable (s1). S2 isn't finished yet, but it is rideable. We styled it with old school cruisers in mind. We'll get some glamor shots of it and post them up soon.

    http://youtu.be/b8_83fws9aM
  14. aka_locojoe

    aka_locojoe

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    Cool video. Wish we had someplace like that to race around here.
  15. Philphine

    Philphine

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    me too. i know there's bound to be some roads around. if nothing else on the eastern side of the state (ky), but i don't think i want to go that far to find one.

    what happened with the s1? some kind of failure? operator error? something with the design that needs improving?

    i think i'll be getting tires soon. if nothing else, i'll try my test hill again to see how much difference they make.
  16. S.I.N. CYCLES

    S.I.N. CYCLES

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    The corner that I crashed in is the second turn in a s turn. It's a long right hander that had been giving me trouble all day. I had just passed Jerome, the guy filming, on the inside of the first turn and took a bad line into the next. I entered too inside and got some kind of bump to my front wheel that almost launched me. I had to straighten the bike to save it and then went heavy on the breaks because I was headed off the road. The crash was all me so I'd classify that as operator error.

    Two things need improving though. One, we need to add steering dampers to our bikes. I put my weight on the front end ie handlebars when I am cornering so if I hit a bump it really throws off the steering. Two, we just need to build our own forks. We made the ones on S2 our of 1" steel plate and 1/8" tubing. They are going to blow hay bails up rather than folding like the cheap forks we used.
  17. Three-Wire

    Three-Wire

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    Those are great lookng bikes, and I'm jealous of your hill! Kansas does actually have a few hills, but they are afraid to put corners on the roads.

    The Coaster's event that I built this bike for was today. It had rained for most of the night but was clearing this morning, and I think the weather scared off a lot of people. Only 4 of us brought vehicles, and including me there were 3 bikes. I got several runs in today, but no video or photos from my cameras. There were a handful of spectators so maybe some photos will surface.

    Of the three bicycle-based vehicles, mine was the fastest. Somehow, this contraption I've built gets off the line extremely well... One of the other local guys who's built several 4-wheeled cars to go compete would beat me down, but I was ahead for the first 2/3 track and he had 50+ lbs of weight on a 150lb car. I ran out of time for balast, so my bike weights about 30 lbs...

    Anyway, the fastest speed my phone's GPS could record was 25mph. It was a real hoot, and I think it'll be worth the extra work to finish. Still have to do some more streamlining, some detail work to improve the rear brake & add removable balast, and the fiberglass/bondo work to finish the shell. Oh, also need good tires/tubes since the crusty old one I was using let go after (fortunately...) my 5th run of the day.
  18. S.I.N. CYCLES

    S.I.N. CYCLES

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    Not finished with it yet, but this is our newest bike. Complete frame up build. You can see it in action in the video we posted above.

    [​IMG]
  19. Philphine

    Philphine

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    sleek.

    no seat this time, or is that part of the unfinished work? a bomb thing is coming too?
  20. S.I.N. CYCLES

    S.I.N. CYCLES

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    We aren't adding any seat to this one. The seat on S1 is basically all for show so we figured we didn't have to add one on this build. We're going to add more weight to it, I'm not sure what aesthetic we'll be using though.

    We definitely got inspiration for this build from the rat rod galleries. So big thanks to all the great builders in this thread and on this site.

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