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Fork Rake on 27"(650b)forks, marketing wank or needed?

Discussion in 'Downhill & Freeride' started by no skid marks, Apr 25, 2013.

  1. no skid marks

    no skid marks Monkey

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    So all the forkers are making 650b specific forks, is this just to assure sales,or are 26" forks that can take 27" wheels going to really feel dud in any way? What does it even counter act? Are the 26s lazier from crown down?
     
    #1 -   Apr 25, 2013
    Last edited: Apr 25, 2013

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  2. supercow

    supercow Monkey

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    English?
     
  3. Tomasis

    Tomasis Monkey

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    i think he meant offset thing.

    Bos forks 650b seem have changed only offset by adjusting steerer/crown thing. Not lowers.
     
  4. ptd

    ptd Chimp

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    Yeah I'd say offset is important when considering the trail measurement, same as all wheel size/head angle combos.

    I'm running 650b on a bike with adjustable HA, in slackest it feels like the trail is too long with too much flop/wheel push/oversteer. With a steeper HA setting it feels fine.

    So I'm interested in the more fork offset being advertised recently (x-fusion/bos/sr suntour) to reduce the trail a bit..
     
    #4 -   Apr 25, 2013
    Last edited: Apr 25, 2013
  5. no skid marks

    no skid marks Monkey

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    Sorry, I was running out the door with Missus yelling at me. Tidied it up a bit now.
    Yeah, that's it. Different fork to steerer angle or axle placement for 26 to 27".
     
  6. supercow

    supercow Monkey

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    Ah I see now, I must admit I also don't understand.
     
  7. dropmachine

    dropmachine Turbo Monkey

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    Since pretty much everything to do with 650b is marketing wanking, why would this be any different?
     
  8. jonKranked

    jonKranked Press Button, Receive Stupid

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    rake is tied to trail, which is tied to wheel size (among other things).
     
  9. zero knowledge

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    Trail (mechanical) will increase by less than 6mm if you go from a 26 to a 27 rim and use the "same" tire. And since this is the Downhill forum, in steering feel that is roughly equivalent to slackening the head angle by 1 degree or raising the crowns by 20-25mm. It can be felt by some of the riders, but it's far from significant. And why oh why would someone want less trail on a go-fast bike?
     
  10. kidwithbike

    kidwithbike Monkey

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    ^^ this guy is an impostor, clearly he is not "zero knowledge" as he purports.
     
  11. Sandwich

    Sandwich Pig my fish!
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    Offset affects trail which affects steering "sharpness". 29ers (THE DEVIL) are bandied about with something called G2 crowns (THANKS GARY) which increase offset and return steering sharpness to be comparable to 26ers (FLICKABILITY). That way you can maintain the same headtube angle (YAW KNOW WHAT I MEAN) as a 26er with similar feel.

    In line with that thought, a 650b (WHY BOTHER) wheel will need a less drastic bump in offset to maintain similar geometries to 26" (NOT FROM MY COLD DEAD HANDS). In practice, most people agree that this is true. My lefty with 650b handles comfortably and not dissimilarly from a 26er (NO PRACTICAL EXPERIENCE ALLOWED) but the lefty has 45mm of offset vs. the more typical ~40mm of a REBAr or Float.

    The boxxer has 42, the 40 has 45mm, the 888 has 46mm, the Durdo appears to have 49.55mm.
     
    #11 -   Apr 25, 2013
    Last edited: Apr 25, 2013
  12. frorider

    frorider Monkey

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    Agree with your first and last points. Not sure I agree with your middle point --- slackening a HA by 1 degree is noticeable, and not insignificant.
     
  13. syadasti

    syadasti i heart mac

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    Most of the latest long travel 29er forks have 51mm. The Lefty Supermax 130mm 29er has 61mm.
     
  14. Sandwich

    Sandwich Pig my fish!
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    yeah G2 is pretty much synonymous with 51mm offset. I didn;t know the lefty superlunch is that big though, that's a lot.
     
  15. zero knowledge

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    Fair enough, but maybe just semantics - significant and insignificant in our statements are the extremes. A single degree HA change is somewhere in between, it won't make the bike unrideable. Going for example from 64 to 63 won't be as drastic as going from 64 to 59.
     
  16. OGRipper

    OGRipper Turbo Monkey

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    I don't know about semantics but 1 degree is significant to me. And of course it's absolutely huge on the internet.
     
  17. demonprec

    demonprec Monkey

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  18. frorider

    frorider Monkey

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