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  1. #1
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    Yet another dual suspension project

    It seems like building dual suspension bikes is la mode these days around here.

    Here's my take at it. This one is made with 120mm travel but I think I might take this up to 140mm. 650Bx2.4 tire clerance, 425mm rear center, 20mm BB drop. I'll probably change the BB shell area reinforcement for some sheet metal instead of tubings.

    I'll probably use a euro BMX bb as a pivot or I'll have some seats machined to fit in in a 1 1/8 head tube (34mm ID)and use someting like 6903 bearings. I thought about Igus composite bearings but I'll need a shouder on my swingarm axle clamp to have enough contact surface so the clamp won't gouge the Igus flange. A little more work but it might be worth it.

    Yet another dual suspension project-581570_10151734218826847_1876936496_n.jpg

    All comments are welcomed.

    Thanks for looking!
    Guillaume

    Cycles Golem

  2. #2
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    My initial impression is that with the size of pivot your planning on using, you may have an issue with clearance in that location. I've used a BB as a pivot, but it's been further up the DT and away from the chainrings. OTOH, looks like you have a 3D model there, so maybe you've already thought of this.

  3. #3
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    What Feldy said.

    I just built one with a headset for the pivot. I put the pivot too close to the cranks and it was a little tricky getting some crank clearance. Moving it up a couple mm shouldn't effect the feel that much.

  4. #4
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    Thanks for the comments!

    If I use a BB as a pivot, I'll have a custom made one at 52mm wide.
    If I use 6903 (30x17x7) bearings I could maybe use a standard 1'' head tube (30mm ID) but I think the pressfit will not be enough for the bearings to go inside. If I use a 1 1/8 head tube, the bearings will be inside the tube in a seat, so plenty of space.

    But, the Igus bushings could give me even more space and save a little weight. I spoke to Igus this morning and they told me it would work quite well for the application.
    Guillaume

    Cycles Golem

  5. #5
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    Awesome !

    I'm assuming this will be all steel ?

    Just talking for talking here but if I had to change one thing on mine, it would be to go slacker on the head tube. I just loooove my frame and 27.5 wheels and the overall layout, how it pedals, how good it feels overall, but I still wish I had gone a degree or degree and a half slacker (from 68 degrees). Been fully over the bars twice now and "almost over the bars" at least 15 times and I'm sure a 66.5 degree would've help on that side of things where the front wheel wouldn't "lock" on a rock as much and throw you over. That's just my 2 cents anyways !

    Cheers !

    Thierry

  6. #6
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    Thierry

    Good to hear from you. How are those Tappered pivot bearings going?

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

  7. #7
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    Hey Thierry,

    Yes, all steel. The 140mm will not have the shock going through the seat tube, it'll be easier to build.

    Right now, I'm playing with the shock placement to acheive the desired rate. It'll most likely be connected to the DT.

    I didn'nt ask when you came, but how did you ream the bearing seats after welding?
    Guillaume

    Cycles Golem

  8. #8
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    Guillaume,

    I reamed the pivot with an adjustable reamer and then press fitted the cups in there, worked out great.

    Are you building this one for yourself or for a customer of yours ?

    Loving to see so many "do-it-aller" dual suspension 650B being put together ! If a guy can only own one bike, that's got to be one like this.

  9. #9
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    I'm building this one for me but a few friends have expressed their interrest into having one.

    Finally, I think I'll put the bearings in the swingarm and have the axle pressed in the frame.

    Here's where I'm at right now with the 140mm I'll name it ''les cent-quarantes rugissants'' or the roaring one hundred forties.

    Yet another dual suspension project-les-140-rugissants.jpg
    Guillaume

    Cycles Golem

  10. #10
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    Quote Originally Posted by Golem builder View Post
    I'm building this one for me but a few friends have expressed their interrest into having one.

    Finally, I think I'll put the bearings in the swingarm and have the axle pressed in the frame.

    Here's where I'm at right now with the 140mm I'll name it ''les cent-quarantes rugissants'' or the roaring one hundred forties.

    Click image for larger version. 

Name:	les 140 rugissants.jpg 
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    How did this project go?

  11. #11
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    Well, I've got a lot going on and I putted this one on the bottom of the pile...

    But, I decided to do something more challenging and build it using split pivot. I'll revive this thread when I'll be there.

    Thanks!
    Guillaume

    Cycles Golem

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