Sick Bike Parts Saved My LIFE!

Discussion in 'General Questions' started by LincolnMercury, May 10, 2009.

  1. Sick Bike Parts Saved My LIFE!
    (a cautionary tale)

    A couple of weeks ago i ordered the basic shifter kit from Sick Bike Parts. Ordered it on a Sunday; it arrived on Wednesday! I had already ordered and received their expansion pipe and used the header portion to install a pipe I had gotten for It was basically the same chamber; the scooterparts pipe had a larger, longer (quieter?) muffler on it.

    Now, a few weeks earlier I noticed the frame flexed under load and could develop a wobble. I had checked all the fasteners and mounting brackets on the engine, and the weld joints and drop outs on the frame. Everything was solid. Still the wobble would appear now and again. It really showed up when I had a 12 back of beer on the back rack. And this was before I had anything to drink; so it was not PIO (pilot induced oscillation).

    Well, the shifter kit was well packed and everything was there. I broke out my tools, red and blue loctite, some rags and commenced to take the bike apart. It was when I removed the engine that I discovered the cause of the wobble. I had wrapped the and wired tied innertube to pad the frame @ the back and lower engine mounts. When I removed the innertube padding from the down tube, I discovered the down tube had fractured; split in two! It was held together only by the lower motor clamp! OH S**T! Then remembered the post about the south FL MB'er that suffed a "mechanical failure" and had to be medevaced. I cannot tell you what a sobering moment that was! I had hit 30 mph while testing the pipe, before I ran out of road. If the top tube or head tube had failed, or if I had hit a bump at those speeds and had a "mechanical failure"? Scary thoughts. And for the record, I wear a helmet and long pants and sleeves and no sandals or flipflops.

    The morale of this story: if it does not "feel right" it is NOT right. Find what it is and do not stop looking until you do. Your life depends on it. If I had not ordered the kit, I probably would have rode until the frame did fail.

  2. nadroj

    nadroj Member

    wow that is crazy, what kind of frame was it(alluminum/steel street/mtn)??? How long have you been riding that frame?
  3. Happy Valley

    Happy Valley Active Member


    It's a good cautionary tale to post and I hope others pay heed.
    Could you fill in a few more details on the make of bike, aluminum or steel, the size of the tubes, etc. and if you used stock mounts and such?
  4. Steel frame, stock mounts... here's a pic of the bike as it was... pic of the damage soon. The frame is a Giant mountain bike frame, and I have been riding it as a MB since July '08.

    Attached Files:

  5. bamabikeguy

    bamabikeguy Active Member

  6. bluegoatwoods

    bluegoatwoods Well-Known Member

    Nice looking bike.

    About how fast did you ride?

    For instance, how long would a 5 mile trip take you? (Info about road roughness would help, too.)

    This'll help the rest of us judge our particular risk.

    By the way, I'm sorry this happened to you. But I'm glad you discovered it before it clobbered you.
  7. Here are the pictures. The frameset is upside down.

    Attached Files:

  8. bluegoatwoods

    bluegoatwoods Well-Known Member

    Do you suppose these frames could be reinforced a bit?

    Maybe a couple of narrow, thin strips of steel front and back. Long enough to stick out from the top and bottom of the engine mounts and be securely clamped to the frame. The motor mounts would "work" against these strips and the strips would spread that force more along the frame.

    It should work in theory. But I suppose those strips would need to be very hard. But that shouldn't be a big problem.

    Or what about simply driving a spare seat post down to the bottom of the tube? Or maybe both? This is sounding like a stronger mount to me.
    Last edited: May 11, 2009
  9. Pablo

    Pablo Motored Bikes Sponsor

    The real good news here is that you got some warning!

    I did something pretty crazy with my HT mountain bike (formerly know as Prince, I mean Diamond Back). I noticed that the 1 1/8" seat tube ID is a perfect fit for 3/4" water pipe. So I tapped a piece in. Heavy as all get out, but HD as well. Both my rear clamps are on this portion of my seat tube. I overestimated the length I would need so I had to hack 1/4" or so off my seat post. No biggie - I do worry about where the two parts meet internally in the seat tube, but I'm always inspecting that section as it's in clear view.

    I always worry about any frame on any MB - we all should! I worry about my stock front mount doing the buzz saw cut in my down tube. I need to take the time to install a SBP universal front mount.
  10. Pablo,

    You have a LIFETIME customer in me! The fit and finish of your parts are excellent. I am a hobbyist machinist and woodworker so I have an idea of the hours of R and D you put into your products. Just the way you packed and shipped the products speaks VOLUMES about your commitment to your customers.

    I am building a 2nd bike. which will have your shifter kit and pipe. Thank you and Ghost for your innovative ideas!
  11. Happy Valley

    Happy Valley Active Member

    Steel, huh?

    I just showed those pics to my bud who is a custom frame maker.
    He shrugged and said he'd never seen anything like that, of course he's not into MBs. About his only comment was extreme fatigue on what he guessed is probably the thinned mid-section of double butted 4130 chromoly.
    He also asked and hard to tell exactly from the pic but is there any corrosion showing up there where it was wrapped?

    Double or triple butted tube sounds good and it is for stress relief in tube joins and welds on a standard bicycle frame though by nature the tube thins in the mid section for weight reduction.
  12. duivendyk

    duivendyk Guest

    I've been calling attention to these metal fatigue induced potential frame failures for quite some time now.The microscopic cracks are invisible until the structures is weakened sufficiently to start bending,it then typically fails catastrophically,when subjected to sudden extra stress.Thin wall aluminum frames are esp vulnerable.If it doesn't feel right (steering) take action!!.