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  1. #1
    Pinball Wizard
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    Anyone run 16" or sub 16" chainstays? Plus, other geo. ?'s

    Hey,

    Well, I'm thinking of having a custom frame built and currently debating geometry. What Does anyone here run sub 16" chainstays? I'd like to keep the rear end as compact as possible. So, thus my proposed geometry is as follows:

    HA: 69* w/ 5-"travel fork
    SA: 72*
    Eff. TT: 23" or so
    BB: 13"
    Chainstays: 16" (or shorter)

    If I can swing it ($$), I'd like to run a Talas fork, to shorten the travel/steepen the headangle when needed. Or be able to run a shorter rigid fork, without screwing up the geometry.

    Now, I have no idea if any of this would actually work, but I'd like to come up with something similar to the Evil bikes geometry.

    Thanks in advance,

    Colin

  2. #2
    all hail der Fuhrer Bush
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    1,635

    15.9"

    my Alpinestars ti mega e-stay frame has 15.9" effective chainstay length, effective since there actually ain't no chainstay there as it's an e-stay design.
    I raced a few times on an M-16 American provided me. I really liked that bike a lot, 16" stays.
    Also liked Fisher's Montare with the curved seat tube and really short, like 15", maybe 14.5" even, stays.
    One bad thing about short stays it increases the chain deflection angle when cross chaining gears. You get a little more chain noise in the big cogs, you got to trim the front cage more in all rings when shifting in the rear. I run mine as a 2x7 with a short bb spindle so I can run the big ring down to the second largest rear cog without issues, and can run the small ring on the small cog no problem.
    Stock setup was problematic. With a tire larger than about a 1.95 in back, the front derailleur cage would literally rub against the knobs when in the granny ring.
    I would caution you to defer heavily to the opinions of your eventual frame builder. I've seen a good number of true custom frames designed by their owners and built to their specs against the best advise of their eager-for-business, usually small struggling, builders. (Personally I wouldn't deal with any framebuilder who would build me a frame to my spec if he wasn't happy with the design. But some will). Mostly road frames. Lots of problems like too light top tubes that caused speed wobble; or funky rake/trail that caused the bike to weave side to side at speeds below like 15 mph.

  3. #3
    mtbr member
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    Do it!

    I've been designing my next bike and have ordered the tubes for a bike that should have 14 inch chain stays. I should be able to run a 2.3 inch tire, max. With a 2.1 I will be able to pull it in another cm or so. My current bike sits at about 15. Don't be afraid of going shorter. Remember that singlespeeders stand ALOT. That makes a big difference in design. You don't have to worry about chain crossing or any of thatgeary stuff. Short is better.

  4. #4
    Doesntplaywellwithmorons!
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    i have a ti mega also and have reconfigured it into a 1x8 setup just to get away from needing the front derailleur so I can have my fat tires. There's room in the stays to get a 3" wide tire in between them but the front derailleur cage prevents it otherwise.

  5. #5
    meatier showers
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    15.75"

    Quote Originally Posted by futonrvltnst
    What Does anyone here run sub 16" chainstays? I'd like to keep the rear end as compact as possible. Colin
    My Vulture's chainstays are 15.75" with the eccentric rotated to the center of the EBB shell. I like it a lot.

    That's an understatement.

    --Sparty
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    you wanted to be.

    Quote Originally Posted by riverrat
    Jaybo... quit *****ing and move to Texas

  6. #6
    mtbr member
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    15.5" funky tandem style bottom bracket

    I have 15.5" stays on my old Dave Yates. The bb is extra wide at 134mm axle length so the front mech is a braze on hybrid built up for me by the shop.
    The long axle keeps the chain angle correct and the braze on front mech keeps the mech out of the way of the tyre.

    Climbing traction is awesome, but it's an old frame, so it's short and that means it used to beat me up on descents. Make sure you have enough length to stretch out and build some flex into the seat stays because you'll get none from the chainstays when they're that short!

  7. #7
    mtbr member
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    Short c-stays!

    Well, I rode and raced both the Fisher Montare and an Alpinestars Al-Mega (designed by the same guy) that had the curved seat tubes and the ultrashort stays. The comments about short stays and chain angles are spot-on: both those bikes had issues with chain angle (the Fisher was an example of chainstays too short to work well with a front derailleur), but those issues are moot with a singlespeed.

    Both the Fisher and the A-Stars climbed like a scalded monkey, and were particularly well suited to out of the saddle climbing like an SS rider might be doing anyway. Both had long top tubes ("Genesis", before it got a cute name) to compensate for the short rear ends. If I could find an Al-Mega in good shape these days, I'd make it into an SS in nothing flat!

    Go with the short stays, you'll like it.

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