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Thread: Single-Sided,

  1. #1
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    Single-Sided,

    Dual crown, rigid, carbon MTB fork.

    Is "Lefty" a reg. trademark?






    Just spent a couple days getting the molds for these
    (left and right sides) done.

    536 g's. included the weight of a 1/2 x 2 1/8 x 5" hunk of 7001 series for the top clamp and rotor bracket. (should be less after milling).

    Will make one (with both legs for the Fattie) Each leg can be about 30% lighter so wonder what it will weight?

    Too bad I have to break this one

    JM

  2. #2
    will rant for food
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    Man, I know it's kinda structurally silly but when it came to changing flats, lefty forks are so cool.

    Not only do you avoid removing the wheel, but the bike serves as an impromptu stand for the wheel.

    I'd ride a single sided entire frameset without complaining, save for the gawking it would receive.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

  3. #3
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    Cool, you'll be like 1/50 of 1% faster on smooth climbs or something like that.

    Seriously, though, amazing carbon work. Show us the fatbike fork when it's done!

    -Walt

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    Thanks,

    Also going to use these legs for a "linkage/girder" Girvin, Noleen, Fournales/Look, type.
    Along with a single pivot rear on the same frame.
    The mold is "modular" so I can use the front triangle with any (axle width) or the full boing rear.

    Was supposed to get to the frame this week but ran out of cloth after building the molds and some customer parts.

    Takes 10 days for a 100 yrd. roll to get here from my supplier in MI.

    JM

  5. #5
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    Quote Originally Posted by Drew Diller View Post
    ...I'd ride a single sided entire frameset without complaining, save for the gawking it would receive.
    You would, however, only receive the gawking from one side
    Myth Cycles handbuilt bike frames
    Durango, CO
    http://www.mythcycles.com

  6. #6
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    Very interesting! I've been thinking about a single-sided fork also. Can you share more details of the fork/hub interface? How are you securing the axle to the fork leg? Thanks!

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    Have the "convertible" hubs that come with 15, 20mm and QR adapters.

    Will turn a custom axle with the 20mm at the fork end tapering to (whatever I need to adapt the QR cup side. (just to clean that side up, making it almost flush-mounted like some trike hubs. 10 mm Ti fixing bolt. (6 mm at the other end)

    Just pulled a 15mm axle off one of my trike builds to mock-up.

    Dropped 4- 45 lb plates on it from 4 feet today. Bent my fork jig.
    The single-sided thing is hard to jig up. (for testing.

    The Euro test drops 90 kilos from 1 meter. Then they "cycle" test for tens of thousands of cycles under load. That was a test I could not (easily) replicate when testing my race bike forks.
    So I dropped the 180 lbs from 5 feet 5 times. Then put it on a friends press with a strain gauge and it took 27-2900 lbs of force to break (tested 3 forks total)

    Am going to just go ahead and run this fork as is and pay attention.
    Can add some rivets and/or bolts to back up the adhesive on the lower tree plate.

    There are a couple methods I could use to secure the trees that would be fail-safe.
    If a customer HAD to have one of these on a build I might go that route?

    Was messing around with the girder linkage geometry between coats of PVA today.

    A single-sided linkage fork might ROCK?!

    Laying up the main frame tomorrow!!!
    Will spend the rest of this week on this (vanity;-) build.

    JM

  8. #8
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    Impressive! Thanks for your response. Looking forward to pics of the completed fork(s).

  9. #9
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    Amazing work there, JM. That is SO cool!

  10. #10
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    Interesting.

    Black Cat Bone Bikes used to make a tubular leg with a similar hub interface that Cannondale uses.
    See http://forums.mtbr.com/weight-weenie...ty-739740.html

    There was also this bladed attempt LAME | eliflap

    (maybe you've already seen them)

  11. #11
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    I honestly had not seen it done before.

    But I KNOW, there is almost nothing you can think of that has not been tried/done before.

    Man, that's so "2011".

    Thanks!

  12. #12
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    Of course Italiano :-)

    Man, that Black Cat has some spectacular pricing!

    JM

  13. #13
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    I know this is ancient ... but how'd the fork end up looking?

  14. #14
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    Been so long I forgot my password?

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    Fair.

    Did you ever get a ride in on the fork? It looked like a great project.

  16. #16
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    Bike has been ridden hard all over the usual Front Range trails and up in the mountains.

    Could get the 2.4's to rub going over some woops at a BMX type section.
    Ended up running Kenda Karma 1'9's. Same tries I run on my other 29'r for years.

    Been on rocky stuff. Nothing extreme.
    Prefer buff single-track high speed riding.

    Thanks

    JM

  17. #17
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    The fork does deflect as you would expect.
    Nothing drastic.
    Ended up beefing them up below triple-tree.

    Was just looking around the shop at un-finished projects.
    There are a set of the same legs, (left and right) sitting there along with the "three-spoke carbon, air-tank/expedition wheels"

    Need to finish them and either mount up to existing Fat-bike frame or go ahead and build a new frame same as above with wide rear and both seat/chain stays?

    The front triangle is modular so I can run any rear triangle I want.

    JM

  18. #18
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    Enough about the fork, tell us more about the bad-ass asymmetrical rear triangle! Certainly makes chain replacement easier... How does it hold up torsionally?

  19. #19
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    I can only imagine there is some flex. Awesome to hear it's been holding up for some good riding. Seems like you know your way around a layup.

    Are you doing the layup on each side of the frame mold and then bonding them together?

  20. #20
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    Yes,
    should have specified; the rear tire moves up and to the left as expected/predicted.

    Enough that when getting a (little) air over the whoops I could get the 2.4's to graze the seat stay. Actually like the 1.9's better for the weight savings.
    Brakes and crank are quite portly. (still have 2 full sets of XT brakes leftover)

    I DO build everything in "two halves" with a spline or "joggle" bonding them together.

    The way I have been doing the stays. They are complete when molded so no secondary bond there.

    Re-inforced the chain-stay when I beefed the fork.
    Could have also beefed up the seat stay but this frame was only slightly over 3 lbs.

    They are also building some aero TT bikes this way. I have built tubes (tapered and radius' of course) and just bonded the or made lugs also.

    Frames can be stronger with less gluing surface area when bonded on centerline.

    Also looks cool as hell have the herringbone pattern at the seam :-)

    Need to make some fat fenders. With the "two-half" method I can change the width with one set of molds. A little heavier for fenders but stiffer w/the spine at center.

    JM

  21. #21
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    Do you think you could compensate for the flex by changing the layup? It's a rad design..

    I was looking at your molds that you used, how much overlap or surface area do you tend to use for putting the 2 halves together?

  22. #22
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    Hey,
    I "compression" mold the "spine" and make it at least 1/3rd bigger (wall thickness).

    All tubes are thicker at the tops/bottoms. Or front-back on a ST.

    Could always add more carbon here or there. Completely happy with the ride and strength on this one.
    Another option was/is installing a rear fender (beefed from from SS to CS)

    Would not sell this type of frame. Would just use traditional seat/chain stays.

    Need to get going on one with the 650B+ rear end.

    JM

  23. #23
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    Good stuff JohnnyMagic. These days I can more fully appreciate that two-halves approach of carbon layup. First, since fewer variables are involved (say, a pressure bladder), there are fewer sources of potentially fouling the layup. Second, and partially intwined with the first, is the idea of less consumables / waste material.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

  24. #24
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    In Formula 1 and military (jet fighter) circles,
    bladder molding is AKA a "blind" lay-up and has to be X-ray'd before it can be used.

    There is another term that escapes me. (derogatory).

    Easton used "lost wax" casting for years and still does.
    Love me some compression molding.

    Thanks!

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