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  1. #51
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    Shirk, the pivot is in exactly the same location as the heckler and that is why I moved it there. I borrowed some 83mm DH cranks from a buddy, I'm gonna go check those out in a minute here after a recuperate from a long day of riding (and crashing - yeesh).

  2. #52
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    Must just be optics, I thought it looked like you moved is back towards the seat tube.

  3. #53
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    Hmmm, nope.

    Well so the cranks clear no problem, chainring clearance on the other hand... that's a no go by a good .30". Bummer. I think I'm going to go for internal bearings. I'm sure there's something that's 33.9mm OD with a reasonable axle. i've got some tube I can turn down a tad and braze into the pivot tube. I might still use star nuts on the end of my axle to keep things in, maybe i'll turn some giant end caps to keep things clean in there, or heck, even use washers. ****.

  4. #54
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    Adarn

    What O/D is the pivot shell that you've brazed in there? If you could get it reamed out to 37mm, you have the choice of 20 or 25mm axle using 6904 (20mm) or 6805 (25mm) series bearings. If you can manage only 35mm bore, you are locked into a 17mm axle. It would be a special bearing to have an O/D of 34mm.....

    Eric
    If I don't make an attempt, how will I know if it will work?

  5. #55
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    yeah, I could only really use a 5/8" axle with the 33.9mm bore i have, it's a HT for 1 1/8" steerer. I actually think I might be able to get the current set up to work. I'm going to go ahead and try, worst case I'll resort to the internal bearings, but I may as well go ahead where I'm going now.

    I was checking out Walt's single pivot project digging back through his blog. I might end up going with .75" x 1.5" square tube like he did for the uprights of the swing arm. I think I can make my axle sleeve/clamp things the thickness of the inside of that tube (.654"). then I'll miter the square tube so that the edge of the clamps are exposed and the end caps can rest in there. It looks like this should clear the chain ring with not much room to spare.

    Boy am I learning a lot on this project! Probably won't make more progress until this weekend, but I'll update when I do. In the meantime, any and all advice is welcome...

  6. #56
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    Hey;

    It doesn't take much detail to make my head hurt, but my advice would be to sit back and stare at it for a while. Look some more at other production and custom builds for ideas. There are likely a zillion ways to accomplish what you want, but the slickest of them usually do not occur on the first thought, for most people. You've got some ideas from others, and that which is in your own head already. Let that all perk for a bit. In some cases, inspiration comes very quickly after you find that you were wrong the first time (like my Kroozer DO-to-CS mitering style, which came like a flash, within minutes of discovering initial failure).

    Most of the time, at least for me, it takes time for that brightest light to come on, and it generally starts as a soft glow before it becomes that blinding light of ultimate clarity!

    -------------------------------------------------

    Never really gave it much thought, but my first impulse is to do something with the parts and characteristics of an ex-bearing crank setup!
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  7. #57
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    mmm, looks pretty tight in there.

    not really put much thought into this, but i did think this when i first saw the head-on image:

    I recon you could face a few mm off each end of the pivot tube, probably 3-4mm each side, depending on how the cups interfere with the suport post. File the brass down a little to match. I also had a look at one of my spare headsets, and depending on the make up of yours, you could probably shed those plastic dust caps, and replace them with a thin washer. just as long as you have the tapered split ring (that one that interfaces between the bearings and the steerer), you should have good contact, and no play. getting the right washer to fit might be tricky, but I am sure you could find something in the spares box, or fabricate something. That will gain you a few more precious mms.

    if the above still doesn't give the clearance required, you can still go down the bearing/17mm axle route later.


    Hindsight is a wonderful thing, and it might have been wise to go for a 41mm ID tube, and a pair of Integrated headsets (or 44mm and some ZS44 headsets)

  8. #58
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    Access to a lathe? Spin up new dust caps that are shallower.

    Are the lower cups a lower stack height?

  9. #59
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    TrailMaker-

    Great advice. I was pretty frenzied when I posted last and I've given it some more thought. I also had a chance to look at a lot of FS bikes to day to try and source some inspiration. But yes, I do think giving it time is key...

    And Toby,
    I already have the pivot tube faced into my fillets, so no more there. the dust caps are taking up a good 3mm more than they need too, but it looks like with this low quality headset, taking them off would be a lot more trouble. As you said if this doesn't work I can always go to internal bearings. I think I'll pursue my smaller clamps, welded inside of the vertical swingarm and see where that puts me.

    Thanks all!
    Adam

  10. #60
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    Inspiration is a funny thing....

    I still marvel at my DO mitering scheme for the Kroozer. Yes... I am marveling at myself. I don't really think it is always a bad thing to be impressed with what you do. That's where enjoyment comes from. Let's be honest. As has been said by more people than just me, that layout is brilliant, simple, elegant. No false modesty here, for it came upon me in a total flash, as if from some other realm. I fiddled and puzzled and agonized over the original layout, endlessly, and reached that point of despair you get to when the reality that is staring you in the face lets your concept down flat. In a relative instant thereafter, the solution I came up with just landed in my brain so much by surprise that it doesn't even feel like it came from me... somehow. That's why I am able to describe it as if it were a third person experience. Just like that, and shazzam!

    All this by way of saying you never know when inspiration will strike, and just how inspired it will be. Hopefully for you, the one you now seek will not show itself in the process of frame #21!
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  11. #61
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    Hey Adam -

    FWIW, I actually used a BB shell and Euro BMX BB (for a 22mm spindle) on mine back in the day. The Euro BB's are nice and low profile so total width isn't an issue and you can just machine down a crank axle (BMX cranks are usually 3-piece). Super easy. I also used a bit different pivot location, though. 1" (or 1 1/8) headsets will work great too but not where you've got your pivot.

    Honestly I would go ride, think about it for a few weeks, and maybe start over. There are probably ways to salvage it but you're just going to end up wanting to redo it anyway, so why not save yourself a lot of bashing your head against a wall and start fresh?

    -Walt
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  12. #62
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    Hey Adam,

    Would forgoing the dust cover and using sealed bearings give you enough room?
    From what I see you should save about 5mm of space.

  13. #63
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    Hey Walt,

    That hurts to hear a lot. I really didn't think this through enough (like I said, learning a lot on this one).
    The sad reality of building a bikes is that the frame is pretty much the cheapest part when you build it for yourself. I think I'm going to try it out and see how it goes. I suppose worst case I could weld some stays onto the back of this and make a DJer and then I'll have all the components for FS#2.

    I am sure there will be a lot of head bashing, but that's really how I learn best and I think it can help make the second one better.

    And crispy, It's going to take some modification, but tat is part of my plan now.

  14. #64
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    That's an 1 1/8" headtube for the pivot housing? That should be a 33.95mm ID, which is pretty close to the inside dimension of a bottom bracket shell anyway (33.6-33.9 mm). So you could tap it and run Euro bmx cups, or maybe even turn the threads off the cups and press fit them in.

  15. #65
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    Good news everyone

    I got a chainring, lost the giant dust caps and shrunk my clamps.
    This looks good enough for me.


    Added bonus: the pivot acts as a chain guide, haha.

  16. #66
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    So you're going to run an outboard ring only? You could easily do an offset rear end to get a nice chainline (and end up with a dishless rear wheel, bonus!)

    Let us know how it rides!

    -Walt
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  17. #67
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    Following on from the head tube / BB diameter part of this adventure.

    I re-call some time ago coming across an advert by a builder who converted older 26" geared frames over to eccentric BB single speeds by clamping the frame on a milling machine and holesaw cutting the old shell out and brazing in the larger diameter Eccentric. Very neat and tidy. This could be done here.

    A thought.. Do you file your mitres or machine cut? A BB cut would take care of the problem, then fit a larger shell.

    Eric
    If I don't make an attempt, how will I know if it will work?

  18. #68
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    That's the plan Walt. This frame is just full of Bonuses!

    I'll be sure to keep you all updated.

    And Eric, that just sounds harder than starting over, which I plan to do anyway. This front triangle is destined to become my DJer, I'll rebuild this thing in the winter.

  19. #69
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    Walt, you used a 19mm BMX Euro bottom bracket, not 22. Probably would work with the 22, but I guess the bearings would be smaller.

    Also, I think it was mentioned to use 2 headset top caps at some point. This would be nice from a symmetry perspective, but I think you might have trouble ever getting it apart since the split rings would be wedging in opposite directions.

  20. #70
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    Alright, well I'll just put this hear for now.


    I've only taken it around the neighborhood and a couple of the "cyclocross" trails near my house, but so far, the suspension actually feels really good. Very minimal pedal bob, a bit of brake jack, but I can stand up and push pretty well and it feels great pumping and going off curbs and stuff. I just wish I had gone with a slacker seat tube (it's 72, maybe 70 would have been better, saddle is maxed out) and maybe a little longer, although I'm running a 50mm stem, so that may explain some of that. heaps standover is good.

    The chain line sucks mega hard though - like reallllllly bad, and it probably doesn't help that the drive train is a bunch of mismatched parts from the bike co-op that I got for $20. I think I can loose a spacer on the drive side, but boy is it hard to keep that chain on. I wipped up a real ghetto chainguide and we'll see how it performs. I can only use 3 of my 9 gears now (partially because I'm using a 6 spd shifter)

    I'm going to ride it at work tomorrow. Hopefully it doesn't explode while I'm out coaching! I'll post more when I see how she does.

    Adam

  21. #71
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    Sick.
    This bike is the most fun bike I've ever ridden.
    It has me wondering why I've been riding rigid SS for so long. I love how it climbs and I love how it descends even more. Geometry is pretty dialed. I'm thinking about a setback seatpost for it though. Shoulda gone more slack. but yeah, time to buy real parts because I am liking this thing a lot.

  22. #72
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    Well...

    What more can you ask for?

    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  23. #73
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    Bump.

    How is the bike holding up after more riding?

  24. #74
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    Hey,

    Thanks for asking, Shirk.

    Well Pretty good. It's a blast to ride. I love descending on it. Yeah, this thing is awesome to descend on. I'm happy with the ride. although I would have slaked my ST a degree or two more and raised the bottom bracket a cm if I did it again.

    I had an incident last week though. I had broken my chain the previous ride and had to take a link out. The next ride I shifted down to climb and sent the derailleur into my spokes and bent it pretty good. ouch. Not discouraged, I figured I'd hike up a ways and go down chainless while waiting for my friends. I didn't realize that it had gone back into my spokes on the hike up and I ended up hopping on an breaking the derailleur and bending my hanger pretty good.

    So It's been like that for a while now. It's fixable but I just haven't had time yet with school starting up.

    But as far as "framebuilding issues" I'd say this bike is working pretty darn well.

    I'm not sure I'm good at describing what's going on with it, but if you have any questions I'd be happy to answer them.

  25. #75
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    Curious to ask about flex of the rear end. With the seatstay tubes overhanging (non triangulated) a couple of inches. How does this feel ? What tubes are they, 7/8" x .049" ?

    I don't know if I'm re-opening a debate here but I guess this debate was more around a chainstay bridge than a seatstay bridge... I'm asking anyways : did you not put a seatstay bridge because it wouldv'e come in contact with the seat tube when suspension is compressed or you just didn't do so because you didn't need one ? I understand the chainstay bridge to be useless because the tubes are usually heavier duty, but I have a hard time looking at seatstays without bridge.

    Keep up the good work. Let us know.

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