(MBBO#05 Class 2) Flashback GT - Done!

Discussion in 'MBBO 2016 BIKES' started by tjwilson, Sep 7, 2016.

  1. LukeTheJoker

    LukeTheJoker Moderator

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    Really nice work going on here!

    Luke.
     
  2. The Renaissance Man

    The Renaissance Man __CERTIFIED DIVER__ (Open Water & Open Dumpster) Pro Member

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    I haven't been keeping track with the builds for the last couple of weeks so I missed a lot here! Incredible job and just what I had expected based on you past work. Keep it up!:41:
     
  3. furyus

    furyus

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    Oh, man, I was there. Those were good good good times. Probably why I'm always drawn back to Sting-Ray builds - happy memories. Of course, back then I pretending I was riding a motorcycle or driving a Corvette (or even a tractor-trailer) when I rode my bike. Now I've done all those things for real, repeatedly, and now I just wanna ride my bike.

    Your build is outrageous. Barris or Roth would've hired you on the spot.

    Marsha.

    furyus
     
  4. tjwilson

    tjwilson Pro Member

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    Thank you very much!

    Just like never forgetting how to ride a bike, That first taste of freedom and the memory how riding a bike made your world grow exponentially seems to have real sticking power.

    Jan.
     
  5. tjwilson

    tjwilson Pro Member

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    Hoped to have a rider by now but, with the welds finished off the frame still had way too much flex. About 1/4" bounce between the rear axle and the top back of the seat... only by sitting on it! A test ride was totally out of the question. Little bit of a set-back although not a complete surprise. I'd received fare warning about the design but was curious enough to gamble and try it anyway. Time for some "additive engineering and re-design". Plan is to add a second side / seat stay and tie that into the first. Strength should come from the two fighting each other as they try to flex. That's the thought anyway. Might also have to add a brace at the bottom of the side and the bottom bracket. Visually that seemed to be where most of the flex was occurring.

    Here's a 3D mock-up of what's planned. Still trying to decide how the top of the new piece will curve and blend into the seat bottom.

    upperstayAdd3D.jpg

    Bending and welding metal.

    upperPiecesParts.jpg

    upperChainstay.jpg

    Pieces roughly positioned to get an idea of how things really look.

    sideviewModInprocess_10242016.jpg

    Also had to spend a little time straightening the frame after finishing off the welds so far. Nothing that the leverage of a six foot 2x4 couldn't fix.
     
  6. The Renaissance Man

    The Renaissance Man __CERTIFIED DIVER__ (Open Water & Open Dumpster) Pro Member

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    That's still aesthetically pleasing and looks like it might be just strong enough! Great solution, keep up the stellar work!
     
  7. Falstaff

    Falstaff

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    Agreed, it keeps the flow and looks great.
     
  8. LukeTheJoker

    LukeTheJoker Moderator

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    Nice solution! It keeps that light and flowing design but will add a lot of strength!
    :dance2:
    I think I actually prefer it, gives it is backbone and muscle! :showingbiceps:

    Luke.
     
  9. tjwilson

    tjwilson Pro Member

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    Thank you very much!

    Thanks Luke, I think I prefer this version too. The original looks kind of anemic when you compare the two.
     
  10. OddJob

    OddJob

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    Beefy, yet sleek. Def muscle bike vibe, with a twist...or make that a 'curve'!
     
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  11. tjwilson

    tjwilson Pro Member

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    Seems the smaller frame pieces take even more time than the larger ones. Agonized a bit over the final curve of the new rear frame support. Originally started out with a curve that was symmetrical top and bottom. Not bad but kind of bland. Ended up with a piece that reminds me of a stinger. I think it visually adds some forward movement to the frame too. More importantly, even though everything is only tack welded, the frame feels sturdy and there's no more flex.

    One of two chain stay bridges prior to weld.

    chainstayBridge.jpg

    Bending seat cross pieces.

    seatBridges.jpg

    The stinger.

    stinger.jpg

    Seat frame in-process. Plan to add a couple more reinforcement pieces.

    detail04.jpg

    Frame to-date details and overview.

    detail01.jpg

    detail02.jpg

    detail03.jpg

    frameSide02.jpg

    frameSide.jpg
     
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  12. pholTmonx

    pholTmonx

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    So glad get the update... Wow dose that look intentional and planned from the start... Really amazing stuff.

    *Edit I really like the seat and stays.... The caged look it gives lools like your holding back a torque monster.. I think it's great effect.. befor looked like it was lightweight bouncer... This screams muscle!
     
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  13. GuitarlCarl

    GuitarlCarl

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    Dude, you could slap a couple pieces of boomerang print formica together for a wicked 60's gone Jetson's vibe tank/panel.

    Carl.
     
    Last edited: Nov 2, 2016
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  14. The Renaissance Man

    The Renaissance Man __CERTIFIED DIVER__ (Open Water & Open Dumpster) Pro Member

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  15. LukeTheJoker

    LukeTheJoker Moderator

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    Coming together awesome! Love the reinforcement, looks better with it than without it!
    Under a month left, going to make the deadline?

    Luke.
     
  16. OneHorsePower

    OneHorsePower

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    Beautiful work !:43:
     
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  17. tjwilson

    tjwilson Pro Member

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    Thank you very much. Appreciate the encouragement.
     
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  18. tjwilson

    tjwilson Pro Member

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    A boomerang pattern would fit right in with Luke's earlier comments about the frame reminding him of a kangaroo!
     
  19. tjwilson

    tjwilson Pro Member

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    Thanks, I'm really liking it better with the added reinforcement too.

    Deadline... there's a deadline!? Well, in the spirit of a bike never really being finished, maybe.

    Feels like I've just now gotten the big picture of the frame's design dialed in. Actually I just have. I really enjoy getting into the finish prep, paint and final details. I wouldn't be able to do much of that by the deadline without it becoming work. I've been thinking a more realistic approach is to finish it off in bare metal. I have other wheels that fit a bare metal build better and have a coaster brake. This would save the time needed to add posts and sort out the v-brakes and cable routing required with the GT wheels. Still have some finish welding, a seat pan that needs modification and upholstering, forks that need the steering tube extended, etc, etc. Long answer, same as the short, maybe. But that would be a more enjoyable approach and goal. I'd always have the option of revisiting the finish details later after the deadline.
     
  20. LukeTheJoker

    LukeTheJoker Moderator

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    Sounds perfect!
    You could always finish it to the next level in the build-off which starts January 1 and allows previously started but unfinished builds to enter! :thumbsup:

    Luke.
     
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