Stretch Build

Discussion in 'Photos & Bicycle Builds' started by lennyharp, Jul 7, 2008.

  1. lennyharp

    lennyharp Member

    OK I have admired Augidog's stretch frame since I joined. I have been wanting a Surley Big Dummy for even longer. So now I will build one for me.

    Today I cut into a perfectly good Diamond Back Apex full double butted Cro Moly frame. datz510 was kind enough to let me buy this off him for what he paid on Saturday $30 on Craigs List. The parts mostly will be replaced, but the frame is solid with a ding or 2 , and now 4 pretty serious cuts. Oh yes I am waiting now on a GEBE kit with a Tanaka 40 that should power it nicely.

    I will try to show what I am doing as I do it. I hope to mount fairly low at say a 45 degree angle forward and make use of the space created between the wheel and the seat tube. The main piece to extend the frame is a tandem tube I have been sitting on for 10 years. I will braze the frame back together with pieces cut and mitered to fit.
     

    Attached Files:

    • cut1.jpg
      cut1.jpg
      File size:
      108.4 KB
      Views:
      314
    • cut2.jpg
      cut2.jpg
      File size:
      138.3 KB
      Views:
      243
    • cut3.jpg
      cut3.jpg
      File size:
      61.2 KB
      Views:
      255

  2. augidog

    augidog Banned

    and the fun begins!

    :cool:
     
  3. lennyharp

    lennyharp Member

    rough draft

    This is where I just get ready to fill in the blanks. I will make a drawing of exactly what I want so I can cut and miter tubes to fit. I may get a board to do the drawing as this is too short er ugly. Gotta have a clean slate to get the ideas right. This is good for the rough draft though. Augi warns not to get too long so I am a little shorter than Surley's Big Dummy frame.

    Here is a photo of one of their bikes. Only costs a grand or so, without the parts. They are a cool company and provide the geometry of the frame here http://www.surlybikes.com/bigdummy.html
     

    Attached Files:

  4. lennyharp

    lennyharp Member

    Here is the rough draft I mentioned. This is to see if what I have will work or if I need to make changes. I can see one for sure and that is the fork. It has too much rake and I will want to change it out for one with less the trail is over 2 1/2 inches and I would like it under 2. It could be I drew it wrong so I will try that part again. Also I did not measure the head angle but did measure the seat angle. The head angle is more important and since I am working with a fixed front I need to redraw with that angle fixed, and the other will fall where it may.
     

    Attached Files:

  5. ozzyu812

    ozzyu812 Member

    No turning back now!!
    Have Fun!! :cool:
     
  6. augidog

    augidog Banned

    lenny...

    when we chopped s-2, we started by jigging the front of the frame at its' original angle...the rest "wrote itself" :cool:

    while it's on my mind...my chain-stay extensions are double-walled tubing, fully weld-penetrated thru both thicknesses.
     
    Last edited: Jul 8, 2008
  7. lennyharp

    lennyharp Member

    I have always wanted jigs but never built or paid for them. What I will show is the ways I have used to build bikes, and hopefully 1) it rides nice and as planned & 2) some other underfunded home mechanics don't let a lack of tooling stop them from trying some ambitious projects.

    Not having all the equipment another has is not reason to avoid a project. You just need to study what is done to get a finished project and develop some ways of getting it done. Lacking jigs I am showing a very effective way of getting the angles right and alignment is another issue I deal with also.

    I used to go to the local frame builders and try to pry experience and advice from their closed mouths. They rarely let much info slip so I could more quickly learn the ways of building great bikes and accessories. This closed information system may be the ways of the industrial revolution where you had to apprentice to learn, but I think we are moved on to the information age where truth and techniques can be discovered more easily.

    Now developing the skills to make the information work is another thing altogether. We can at least share info and experiences and the skills will develop in trying things out. Hopefully in this sharing exercise I will more fully develop my frame building skills. I wish I had a record of some of my other builds from the 1980's and early 1990's.

    I see Zomby Builder posted this previously. http://www.motoredbikes.com/showthread.php?t=8495
     
    Last edited: Jul 8, 2008
  8. augidog

    augidog Banned

    a long "8-by" board is all that's needed, "hilti" it to the garage floor or clamp it to a nice surface...build a riser in the front for the forks/axle, a riser mid-point for the bottomset, some washers and bolts to hold it there, then calculate length, set a riser (even-height with the front) where the rear axle will be, fill the gap...

    only trying to shoot ideas at you, anything to make it easier, eh?
     
    Last edited: Jul 8, 2008
  9. datz510

    datz510 Member

    Lenny, as we say on a 4x4 truck board about tube cages "Needs more triangulation!!" ;) Just ribbing you, my friend.

    I added a couple more members to the frame drawing for good measure.
     

    Attached Files:

  10. lennyharp

    lennyharp Member

    Suspension fork

    Ideas are good. This forum is built on ideas. Triangulation is good too. I am leaving that area open untill I decide where the motor goes. As low as possible without having heel clearance issues.

    Anybody have a suspension fork for a 1" steering tube? After riding for a couple of hours I decided I really should have suspension stuff on this bike. I really love the way my other Diamond Back rides. It is my first bike with suspension anything and now I have about 1000 miles on it and don't know how I rode those other 99,000 miles without it.
     

    Attached Files:

    • lbt2.jpg
      lbt2.jpg
      File size:
      205.7 KB
      Views:
      217
    Last edited: Jul 8, 2008
  11. datz510

    datz510 Member

    Lenny... as soon as I am feeling better, I have everything needed to build a jig for you. I have some 2x4" 1/4" wall steel tubing and a good assortment of small DOM tubing which would be used in plce of axles . The small DOM tubing would then be welded using spacers to the 2x4 tubing to make jig that would be completely rigid. I also have some larger DOM tubing that could be cut and used to locate the bottom bracket. Use a clamp of some sort to secure the frame at this point. At that point, it would be like augidog said.. you just fill in the gaps to make your frame.

    We can talk about this idea next time we chat. I have everything to do this and It wouldnt cost a penny.

    Also, it would be reuseable, as you can cut and reweld steel as needed for different projects.
     
    Last edited: Jul 8, 2008
  12. lennyharp

    lennyharp Member

    Too cool, I knew I shudda stayed in school. We be a team here.
     
  13. augidog

    augidog Banned

    this place ROCKS! good on ya, datz' :cool:
     
  14. lennyharp

    lennyharp Member

    pabickwermert sent me the rear shock he pulled out of his bike and I just ordered a front suspension fork from the shop I worked for for years. They are one of the only places I know to get real obscure parts like a suspension fork for 1". This project is coming off quickly now that datz510 got me started. Sorry no more photos probably till next Monday.
     
  15. DetonatorTuning

    DetonatorTuning Active Member

    FANTASTIC, way to go Lenny, i can't wait to see what you work out !!

    since you posted the Big Dummy pic you are in on what i'm talking about using the extracycle extension on the full suspension mongoose blackcomb.

    i thought of using one of the many "flat foot " bikes for the 68.5* head angle, but they are just too expensive for base stock when i can get the blackcomb for $300.

    keep the pics rolling

    steve
     
  16. revelstone

    revelstone Member

    i like the picture of the bike. i'm getting this engine and putting it on this bike. it comes with the transmission shown in the pictures. should be here friday. how did you manage such a small sprocket on the left side? i've been thinking about a frame mount, but because of the width of the engine (12 inches overall) been thinking about a rack mount. your method looks like a solution i could use. if you don't mind me pirating it from you. could you post some close ups of your rack and gearing? i'd appreciate it if you could.
     

    Attached Files:

  17. brendonv

    brendonv Member

    U should lower ur seat n move it back a tiny bit so it looks more like a chopper, then get some cruiser handle bars. XD
     
  18. revelstone

    revelstone Member

    mods

    possibly but right now i have to help that little engine uphill and the seat hieght helps me do that. if i keep it looking like a bike, i have less worry about police thinking i'm trying to get away with something. i'm not. my new engine is 47cc, 2cc under the legal limit in utah. i'm good.:cool:
     
  19. lennyharp

    lennyharp Member

    On my present bike I use a Staton 18.75 to 1 gearbox and a 11 tooth cog comes off the gearbox. The reverse freewheel on the left side of the special hub from Staton is 16 tooth.

    The seat forward is set up on purpose to put my weight over the pedals more. This is set up on purpose to give my pedaling more power. Also the balance of weight on the wheels is better this way. I have never felt comfortable or in good control of a bicycle at speed with cruiser bars. Actually the thread is about the black bike that I am modifying more than the racing bike I have setup already.
     
  20. lennyharp

    lennyharp Member

    a wheel

    Since I am using the GEBE that uses a clip on ring and was advised to use zip ties to strengthen the wheel I thought I would try a trick I have used in the past to strengthen my wheels. For any wheel builders here the spoke length is the same for this as for a standard build.I basically take the spoke to it's cross point and twist it around the spoke it crosses. The spoke changes direction and goes to the rim hole that the twist companion would have gone to. I have also done a double twist where the spoke ends up at the same rim hole it would have gone to normally. Either way the spoke is braced against the other spoke and makes for a much stiffer wheel. I do not remember seeing this on any other bikes but I did build my last bike for myself with a set of these wheels. I never broke a spoke or needed to true the wheels in 2500 miles of riding. I hope the trick works for the GEBE ring. The wheel is not finished yet and I will do that later and post a picture to compare. Also looked up my original build of Diamond Back with EHO35 Staton gearbox for revelstone
     

    Attached Files:

    • whl.jpg
      whl.jpg
      File size:
      156.9 KB
      Views:
      127
    Last edited: Jul 13, 2008
Loading...