Gravity racer - Calling all daredevils!

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

  1. gcrank1

    gcrank1

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    How much of a drive is it to a good hill? It could make a fun road trip with a few runs and refreshments to follow??? Even though I have some good hills close Im always looking for more, and the best/worst one Ive got in mind is a couple of hours away.
    I put high pressure Bontrager H-2 tires on a cheap cruiser bike c/w a long stem and typical drop bars. A 'nana seat set me back long and low and that rig did almost as well as Morph, so you dont have to spend or do a lot to play. When I look at most of the boardtracker builds I see a decent g-bike ride!
    As to what to do at 3am...........you are on your own..... :wink:

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  2. fast eddie

    fast eddie

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    last night i finished assembly on my latest buiold (minus the brakes cuz it's getting pinstriped) and i cant wait to post pix later tonight, it's my most awesome to date ! id get pix up sooner by i have dinner at my new girfriends hous so im gonna clean up allproprer like!
    fast eddie
     
  3. gcrank1

    gcrank1

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    Bring it on, Eddie!!!
     
  4. Philphine

    Philphine

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    the first test run i did on mine i did at about 1 in the morning. can't say it's that bright of an idea though, but i had it at work doing some stuff to it, got off at midnight and just wanted to try it.
     
  5. fast eddie

    fast eddie

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    the frame is powdercoated, lots of custom welding, it's only assembled this far cuz it's gonna get pinstriped so the brakes/lines would be in the way, the fenders keep the "dirty air" off of the tires, the flat peices welded to the bottom bracket are knee trays -this is where i steer the bike and where my body weight is supported, - they're made from 1/4" angle iron, no seat cuz i dont need one and seats take away maneuverability, lots of goodies on this bike, one of a kind, this is not a stingray frame, this is a long frame made for 24" stretched chopper/cruisers, this bike has a longer wheel base than a 26" bike


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  6. KOTA

    KOTA

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    GORGEOUS, eddie. We're definitely going to need some riding pics.
     
  7. gcrank1

    gcrank1

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    :mrgreen: WAAYYY COOL!
    Cant wait to see it done (gotta steal some ideas for mine, especially the kneelers, I think).
    Ive been going through this whole thread again lately, there is a lotta good stuff in here that I forgot about!
     
  8. Philphine

    Philphine

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    is it longer than the 50" wheelbase they were mentioning before? if it is, are you just not worrying about it any more from where you mentioned there's no sanctioning body anymore?

    hey, also, is that a fork off a 20" bike? if it is is there any way to make them stiffer? i used one on mine and since it's for a kid i wish i could get in it somehow and change the springs or something. like out of a 24 or 26" fork. or have you found it doesn't matter? since i've only ridden mine a couple times i keep thinking it should be stiffer, but it's just an assumption on my part knowing where i got my shock from.
     
  9. gcrank1

    gcrank1

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    I havent tried it on bike forks, but there are a bunch of engine valve springs/weights/dia.s to pick from that can maybe be added or stacked to change compression/rebound rates.
     
  10. fast eddie

    fast eddie

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    the wheel base is about 45" inches, any more than 45 or 50 would take away manueverability in turns so i wouldn't go longer than that, since i gotta get this through sharp turns at 55+mph it cant be too long. the fork is an old school bmx fork so its really stiff and they work great for this application. the forks off of current 20" bikes would not be a good fit for what these bikes are supposed to do, i would not trust them to hold up personally. if you google RST they make awesome 20" forks. i have an RST fork on aother bike im building - i rode that fork for years and loved it. ive heard alot of guys taking the springs out completely and inserting a metal peice so that they're rigid, that way they have the steady of a triple tree fork with v-brake bosses (v-brakes are the best rim brakes in my opinion.) if you bild one or have one i wouold absolutely recomend a stem with at least 3" of reach, and a road bike stem that has a negative dgree angle (points downward) works great, or a mountain bike steem mounted upside down, this will add caster and keep it steady so that you dont have to add a steering dampener/stabilizer. i wont actually ride this with the front wheel disc, its just for shows when i show it at hot rod events, a front disc would catch cross wind and im too chicken to ride with it on there!
    fast eddie
     
  11. gcrank1

    gcrank1

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    The rear V-brake on my Morph (orig. OCC brake) stops way good, I think better than front and rear calipers on my old Brit bike at speed, but then this kind of weight is an issue. I really need to get the front brakes hooked up too.........it was a fork for a 26" wheel (I think), and didnt come with brake arms, so I gotta scrounge.
    Ive got a 4.5" angled stem, inverted, that gets the turned down arc bars bars out front like Fast Eddie says, and it feels good there. I just slammed the original OCC saddle, so sans kneelers I can get on the rearsets and get stretched out on the toptube. It feels promising in the MkIII setup; now to run it! (BTW, the bungee is just to keep the forks straight for the pic)
    Gee Eddie, it aint purty like yorn.........kinda 'ratracer', I guess.........

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  12. gcrank1

    gcrank1

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    Summer heat was a bummer hear and sapped my enthusiasm for lots of things. Every time I thought about another speed run and puttin' on safety duds (gotta be prudent...) I couldnt bear it.
    Well today was the day! Made two runs on different hills; the new one I thought would do better than the 35ish I got out of it (it just didnt have enough drop). We went back to the hill I show above with the silver bike with drop bars and Morph did another solid 45 mph run, and felt sweet too. The next one I want to try is about an hour away and now Im ready for it. I really want to break the 50mph mark!
    Any trials or runs with yours, Eddie?
     
  13. Captain Awesome

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    I grew up in Wisco. Where are you doing your runs at?
     
  14. gcrank1

    gcrank1

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    My good hill close to home (the solid 45mph hill) is not far from Rio, the hill today that didnt get what I expected is by Lodi. The next big run is on Cty B (I think) west of Baraboo just outside of North Freedom (where the steam train is). The most scary one to contemplate is over at Richland Center just coming down into town off the big bluff. It wouldnt be bad except for a pretty hard right hander at the very bottom after a steep drop; if I couldnt scrub off enough speed and swung wide I'd be right headon into the other lane or off into the ditch, fence and field (ugh).
     
  15. Captain Awesome

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    Very familiar with that Baraboo area as well as Richland Center
     
  16. GuitarlCarl

    GuitarlCarl

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    ANYBODY STILL BUILDING AND RIDING THESE???
    We have a wood bike build coming up and I put two and two together...
    I can just see me disintegrating into a big pile of splinters...
     
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  17. gcrank1

    gcrank1

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    Im thinking about doing a 'big version' with my Dyno Deuce. Its easy to swap the bar clamp and bars as an assembly to a low down and just leave the pedals. A set of rear BMX pegs and a slammed seat, ala boardtracker, then max the air in the big red bricks (presta valved). Should get a bar mount for the Garmin, too.
    This should be a dandy use for some of the boardtrack builds! How about it guys? Do G-Run with yer 'trackers?

    My other idea, if one kinda falls in my lap, is the new generation of suspension mtn-bike c/w disc brakes. Some high pressure 26" tires, slammed seat, low bars and rearsets would do it.
     
    Last edited: Dec 6, 2013
  18. LukeTheJoker

    LukeTheJoker MUSCLE BIKE BUILD-OFF! Moderator Pro Member

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