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  1. #1
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    Another Full Suspension Build (2nd times the charm hopefully)

    Some of you may have seen my last electric fatbike build, which was a success and failure at the same time. Though it's extremely fun to ride and handles very well, it turned out to be a moped and not a bicycle. I'm hoping this build will be all bicycle. I started getting parts ready for this build about a month ago. They include 80mm rims with surly nate tires, surly crank, bionx sl 350 electric hub motor, and surly horizontal dropouts. The rear hub is offset 17.5mm (similar to a pugsly). I should have offset it more than that, but had enough trouble getting the 17.5mm because of the narrow flange width of the bionx hub. I chose this hub because it amplifies a persons abilities. Which in my opinion is why bicycles were invented in the first place. This bike will have similar front and rear suspension as the last one. Using bearings on the bottom bracket shell and a modified noleen girder fork. The tubing is .035 wall 4130, with 1 3/8 for the main triangle and 3/4 for the rear stays.

    Here are some pictures of the progress so far. I also made a new frame building jig out of 8020 aluminum and that has helped me a lot.


















  2. #2
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    I guess you do some farming...

    As I recall, the BB-centric suspension designs of the past didn't pedal all that well, which is one reason they didn't catch on. How well does such a design work with the hub motor?

  3. #3
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    It will be interesting how your spring/shock arrangement comes together, as there is significant unsprung weight there to be compensated for.

    It looks awesome so far!

    Sent from my iPad using Tapatalk HD
    Where am I? Again.

  4. #4
    will rant for food
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    Hubba hubba.
    Latitude: 44.93 N

  5. #5
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    Cool;

    I am - of course - curious as to how you are bending your tubing? I assume it is not by running it over with the background implements...
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  6. #6
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    Quote Originally Posted by TrailMaker View Post
    Cool;

    I am - of course - curious as to how you are bending your tubing? I assume it is not by running it over with the background implements...
    what you've never seen farm equip capable of artistic tubeantics??

  7. #7
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    Quote Originally Posted by Andy FitzGibbon View Post
    I guess you do some farming...

    As I recall, the BB-centric suspension designs of the past didn't pedal all that well, which is one reason they didn't catch on. How well does such a design work with the hub motor?
    Since I never pedal the first build and have never used a hub motor before, I'm not sure how well it's going to work. Hopefully it turns out okay. Thanks for the response.

  8. #8
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    Quote Originally Posted by VanSyncro View Post
    It will be interesting how your spring/shock arrangement comes together, as there is significant unsprung weight there to be compensated for.

    It looks awesome so far!

    Sent from my iPad using Tapatalk HD
    Your response is the reason I posted this here. That was something I hadn't thought of. Do you have any ideas on how to compensate for unsprung weight? Thanks for the input.

  9. #9
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    Quote Originally Posted by TrailMaker View Post
    Cool;

    I am - of course - curious as to how you are bending your tubing? I assume it is not by running it over with the background implements...
    No farm equipment was harmed in the making of this bike. I use the Harbor Freight tubing roller with Swag Offroad dies. It works fairly well, but I can't seem to make very tight curves without distorting the tubing. It works really well for gradual curves.

  10. #10
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    Quote Originally Posted by Riverbend Bicycles View Post
    No farm equipment was harmed in the making of this bike. I use the Harbor Freight tubing roller with Swag Offroad dies. It works fairly well, but I can't seem to make very tight curves without distorting the tubing. It works really well for gradual curves.
    Hey;

    I love the compound curve look, but I can just see the hint of some distortion in the tubes.
    I imagine it shows more closer up. Still, it seems like a lot less than I would have thought
    possible. interestingly, it seems far more noticeable on the ST than in the front tubes,
    which seems odd. I was under the impression that you would not be able to roll a tube
    thusly because you always get a distorted portion of tube just beyond where the pressure
    die reaches. 6" of scrap at either end with a constant arc bend like these.



    It occurs to me sitting here that you might be able to avoid the "distortion zone" by
    ratcheting the tension down as you roll, and then taking it out as you stop at the end of
    the radius, thereby "blending in" the distortion more smoothly and over a larger area than
    if you just stop. The real problem is getting it tensioned in the same spot all the time, and
    then keeping the bends in plane. I find the tube likes to wander A LOT in that roller. It
    doesn't seem to matter with one arc, but doing plane of bend radii would make it a lot
    tougher.

    I would have given that a go, but did not think it possible, was not willing to accept highly
    visible distortion, and did not want to chance wasting expensive tubing. However, I'd say
    you've had reasonable success. Care to share how?
    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. #11
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    Quote Originally Posted by TrailMaker View Post
    Hey;

    I love the compound curve look, but I can just see the hint of some distortion in the tubes.
    I imagine it shows more closer up. Still, it seems like a lot less than I would have thought
    possible. interestingly, it seems far more noticeable on the ST than in the front tubes,
    which seems odd. I was under the impression that you would not be able to roll a tube
    thusly because you always get a distorted portion of tube just beyond where the pressure
    die reaches. 6" of scrap at either end with a constant arc bend like these.



    It occurs to me sitting here that you might be able to avoid the "distortion zone" by
    ratcheting the tension down as you roll, and then taking it out as you stop at the end of
    the radius, thereby "blending in" the distortion more smoothly and over a larger area than
    if you just stop. The real problem is getting it tensioned in the same spot all the time, and
    then keeping the bends in plane. I find the tube likes to wander A LOT in that roller. It
    doesn't seem to matter with one arc, but doing plane of bend radii would make it a lot
    tougher.

    I would have given that a go, but did not think it possible, was not willing to accept highly
    visible distortion, and did not want to chance wasting expensive tubing. However, I'd say
    you've had reasonable success. Care to share how?
    Reasonable success is the key word here. I know exactly what you're talking about. I scrapped a few attempts because of this. I had a lot less trouble with the .049 wall tubing on the last build. My method is to start wide and work my way to to middle of the arc. That way the distortions aren't in one place. I have to confess that I then sand and file away the ripples that are caused by the devise. I am very open to suggestions of better ways. What's the best way to bend tubing in your opinion? Thanks a lot for the input.

  12. #12
    All Lefty's, all the time Moderator
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    Totally hot.

    Subscribed.

    As for BB concentric FS designs? I dunno. My Lenz Milk Money is pretty sweet, I think any complaints about pedaling efficiency come from the old days of single pivot with a coil over.

    How much travel are you aiming for? And the obvious self aggrandizing question would be,(since I like the Lefty so much) what fork do you intend to use? Or are you building your own, (looks like you're fully capable...)

    Modern air units with platform damping and good low speed compression damping have pretty much put the "single pivots are crap cause they bob" arguments to bed.

    Love the farm implement motif as well, though I'm sure it's simply environmental and not for looks.
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  13. #13
    will rant for food
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    Quote Originally Posted by MendonCycleSmith View Post
    Modern air units with platform damping and good low speed compression damping have pretty much put the "single pivots are crap cause they bob" arguments to bed.
    I've gotten that impression from a few folks on the frame building subforum as well. They weren't as enthusiastic, but the same vibe.
    Latitude: 44.93 N

  14. #14
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    as far as the bb centric bob problem, I would not worry about that with a multilink setup, as it appears you are building. I see that your dropouts are in the chainstays, so it won't be a Horst link(brake mounted to seatstay). That will cause some brake induced forces compressing the shock, which at the higher speeds may be a good thing, As far as controlling the extra unsprung weight, talk to the shock manufacturer to make sure it has plenty of damping adjustment in both directions. You will probably want to make the linkage to the shock progressive, so it will ramp up damping at the end of the travel.

  15. #15
    All Lefty's, all the time Moderator
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    Quote Originally Posted by Drew Diller View Post
    I've gotten that impression from a few folks on the frame building subforum as well. They weren't as enthusiastic, but the same vibe.
    Yeah, been on SP bikes for years, and they did bob. With smooth pedal stroke though, not obnoxiously so. Same time, riding other designs, I just don't like how the mute the activity of the suspension. They either get spiky or do weird things like make the back end of the bike feel like it's breaking off.

    Add modern units to the SP and they just come into their own, at least IMHO.

    Sorry for the minor thread derail.....
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  16. #16
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    Quote Originally Posted by Riverbend Bicycles View Post
    What's the best way to bend tubing in your opinion? Thanks a lot for the input.
    Ahhh...

    The age old riddle. The answer is any way you can, and unfortunately there are many ways NECESSARY to get any particular job done. In other words, it is very bend specific as to what process you use.

    I have a Pro Tools 105 draw through bender that has proven to work extremely well for relatively tight radius (3.5CLR) bends in small stay tubing (I too have been using .750x.035). It leaves what I feel is an acceptable amount of distortion in the tube. I have not tried bending large thin wall tubing with it yet. Somehow I'm guessing that I might be inclined to accept more distortion in a stay tube than a main tube, and I'm not at all sure that it would bend larger stuff at all, let alone with an acceptable amount of distortion. I measured around .025" change in tube diameter on the .075. I'm not sure if it would bend the bigger stuff with so little distortion.

    However, that is not the right tool for these large sweeping arcs. For instance, the largest CLR die you can get for that bender for 1.375 tube is 6"CLR. I imagine your bends are larger radius than that. You would have to have a relatively tight bends with some amount of straight tubing in between them, and this would quash the vibe.

    The tube roller is obviously problematic for these types of tubes as well. Getting a nice smooth arc in one direction is not problem, but you will always have that big lump at each end.

    I would wager that any tube that was formed to a shape such as you have created, and had no distortion in it to speak of, was hydro formed in some fashion.
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  17. #17
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    did you have to cut up a perfectly good pugsly to get those chainstays?
    or, did you somehow get the dropouts, and make your own?

  18. #18
    Frt Range, CO
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    Quote Originally Posted by autodoctor911 View Post
    did you have to cut up a perfectly good pugsly to get those chainstays?
    or, did you somehow get the dropouts, and make your own?
    Surly sells 'em:
    Universal Cycles -- Surly Cast 4130 CroMoly Dropouts

  19. #19
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    I was able to get some work done on the front end of the bicycle. This is my second fork using the noleen linkage. I used the same 1 3/8 x 0.035 wall tubing. The forks take some time, but actually aren't that difficult to make. A lot of the time is spent machining the axles and the attachment points to the tubes. I've really enjoyed the fork on my other fatbike and feel this method of suspension handles very well. Though I should mention that I'm not as experienced a rider as a lot of the participants in these forums are.




  20. #20
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    Great job I am jealous!
    Happy holidays to all my Fat friends !

  21. #21
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    Wow!

    Unique doesn't even scratch the surface! Can't wait to see the finished ride!

    So you are a farmer, welder, machinist, and now a frame builder? I must say I am jealous!

    What/where do you farm, and is the welding/machining a necessary part of your farming business?

    I worked on my uncle's alfalfa farm from when I was 12 until I graduated high school. Hard work, but I learned a ton.

    If only I'd learned more welding, my dream of building my own frame may be closer to reality!

    frog

  22. #22
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    Excellent work, love the rolled tube look.

    I've done a lot of tube bending making roll cages and such and the dies always make a visible indention where the die starts. Not a huge deal, but may be an issue visially for you.

  23. #23
    Dinner for wolves
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    Merry Xmas. This thread is so fcuking macho I can't stand it. Tractors as a backdrop? Homemade bent tubing FS e-fatty? This edges out the carbon fiber disc brake pad thread!
    Responds to gravity

  24. #24
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    wouldn't it have been easier to use the carbon girvins as a straight bolt on?

  25. #25
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