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A Bad Case of Drillium!

Bruce went crazy with his drill press, and removed, if I read his notes correctly, about 13.7 pounds from the normally 30 pound Catrike Speed!  This is Catrike #CS754, named Holey Spokes.







Now we need to see that thing assembled, a final weigh in, and a test ride to see if it whistles.  Its just remotely possible that Bruce has too much time on his hands. One last picture:


7 comments to A Bad Case of Drillium!

  • Bruce (trikebldr)

    Clarification! Bob neglected to mention that the 13.7 lbs is from the trike starting at about 36lbs! It sits at 22lbs, 3oz right now, with some lighter front wheels coming from PowerOnCycles, and a new carbon rear der in place of the drilled Deore XL der. That, alone, is worth over 100 grams, or about 1/4lb! When everything is done, it will be well under 22lbs.

  • Trsnrtr

    Careful there, Bruce! I remember the drillium years and also remember a friend laying in the middle of the road, dazed, with a crankarm still strapped to his foot. 🙂

    Of course, at least you won’t fall over! It may be a long walk home, though! 😀

    Pretty cool, though, I must admit!

    Dennis T

  • trplay

    Very nice. Could you perhaps thread the crank holes and have multiple crank lengths?

  • GrantAndre

    Bruce! I don’t know you, and I trust you’re well aware of the risks (stress risers!) and weaknesses created by all the holes you’ve drilled… However, this post still makes me feel like a mom: I’m concerned for your safety! I remember the 90’s, when folks were doing this with Campy parts and other bits to shave weight. Almost all the drilled parts eventually ended up cracked at a stress concentration point created by the hole. If you’re light in weight and light on the pedal input, maybe this will be OK for a bit? Sure looks nice, thought!

  • Today is march 6, 2012, and HS is fast approaching 3 years old, with no cracks or problems. I weigh between 210 and 220lbs, and quite often do stoppies and bicycle this trike just for kicks! I also pull a dog trailer behind it with a total weight, with dog, of 55 lbs.
    Grant, de-burred holes don’t create stress points; they stop stress crack lines, as at the end of the slot in a frame where the boom inserts. If a hole isn’t correctly de-burred, the burr can create a stress point. De-burring is extremely time consuming, and most folks won’t spend the time to do it right.
    90% of the holes and metal removal on this trike was done per computer stress flow diagrams showing where it was overbuilt and where to avoid. The philosophy is that DF’s are built using butted and double butted tubing to save frame weight, but trikes are built using simple, straight-walled structural tubing, so there are areas where their wall thickness is excessive.
    Truvativ Elita cranks (at least of the vintage that are on HS!) have a dog-bone cross section, with the bulk of their mass along the edges of the arms. This leaves a lot of material down the middle that can be removed, especially in smaller circular holes, not slots. I can lock my brakes and mash my pedals hard enough to spin my rear wheel on clean pavement without the cranks arms breaking. I have also stomped on them a hard as I can. No breakage. (I did bend the spindle of one of my chromoly Frog pedals doing these tests!) Yes, drilled cranks have broken in the past! So have stock cranks, and over-drilled cranks!
    This trike was not simply attacked with a drill as most cyclists did intuitively, but blindly, back in the old days! It was analysed first by a computer that controls a building’s earthquake equipment after sampling thousands of stress points. This is far beyond SolidWorks stuff! However, on some smaller parts, like the brake levers and shifters, I did take liberties, knowing they would not cost much to replace if they did fail.
    It was predicted to even fold up around my ears by some on the forums, but after almost three years and some rougher roads, I think it has shown to be a total success!
    I will disclose one part that I would do differently, though. I wouldn’t drill completely through the “peace” ribs inside the boom next time! I get roughly twice the flex from my boom as an undrilled version. I would probably use a boom without the “peace” ribs inside to begin with. Nobody, except Catrike, uses this extrusion, and they don’t have the problems it was implemented to solve.
    The trike does now weigh 26lbs, 3oz, but with 2 frame bags full of tools and tubes, and bottle cages, mirrors, headrest, trailer hitch and newer, heavier Stelvios. The 24lbs is in stripped, race trim.

  • Very cool! I had a friend who was an extremely strong cyclist, who broke off an undrilled crank arm once and crashed. 26 pounds with tools and kit sounds wonderful!

  • Wolf

    Very cool. I take this as inspiration for my modifications of an Steintrike Wild One. Unfortunately without earthquake simulation, but alot of thoughts and less holes. 😉

    Thanks Bruce, looks very well made, as well. De-burring is important, same in machninism environment, as burred holes are not only a stress development factor, but dangerous for the skin, as well.

    Best regards

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