Advertise on Bikeforums.net



User Tag List

Results 1 to 6 of 6
  1. #1
    The Rabbi seely's Avatar
    Join Date
    Apr 2004
    Posts
    4,864
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Unemployment births Frankencrossbike.

    Working 10hrs a week lately, I have had a lot of time to sit at home and stare at my bikes. I continually pose the question... how can I make them weirder?

    I started on the old Schwinn Criss Cross today. It was set up as a 1x9, but the gears annoyed me. Still, I couldn't stand the thought of spinning a 2:1 around town, or mashing a slightly bigger gear in a cross race.

    This spawned an idea, loosely based on the Surly Dingle Cog concept. What if I took a 15t and a 17t cog, spaced them about 2.5mm apart, ran an 8spd chain and a 34t ring...?

    Now keep in mind the bike has vertical drops, so this means I need a tensioner. I think in this case its actually beneficial. I used an old Suntour ARX rear derailleur, mid cage, and wrapped the chain around the rear cog, and then down and through the *lower* pulley, effectively bypassing the upper pulley all together. This gives me a ton of downward tension on the chain, and allows me to leave enough extra chain so I can switch between the 15t and 17t without having to monkey with chain tension. To visualize it--the bottom pulley is actually pulled up so it is nearly touching the rear cog with the 17t cog, and has about 8-9mm of clearance with the 15t. Great tension in either cog.

    Now, I adjusted the derailleur so it would rest below the 15t (outer) cog. I then set the derailleur limits just as I would on a full cassette, adjust the travel so the low limit was right below the 17t (inner) cog. This allows me to change gears by simply pulling the chain off one gear and plopping it on the other. The play I left in the derailleur allows it to make up for the "bad" chainline a bit. Rather than jumping off the cog, the derailleur moves with the chain.

    The chainring sits almost in the middle of the two, so the chainline is only off about 1mm in either gear. So far, works great. Seems like a really good option for anyone with a vertical dropout conversion. The derailleur holds tension much better than a Singulator, and is much easier to adjust. The springs and pivots give a little room for error as well, vs. the static Singulator. Can you tell I've never liked Singulators?

    Anyways, hope to have pictures up soon. Meanwhile, I'm going riding in the snow!
    commuter turned bike mechanic turned commuter (also a Velocity USA employee, but this is my personal account)

  2. #2
    Senior Member DDYTDY's Avatar
    Join Date
    Nov 2006
    Location
    Methuen, Massachusetts
    Posts
    519
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by seely View Post
    This spawned an idea, loosely based on the Surly Dingle Cog concept. What if I took a 15t and a 17t cog, spaced them about 2.5mm apart, ran an 8spd chain and a 34t ring...?
    How about a friction bar end or down tube shifter for a two speed?

  3. #3
    cycle-dog spot DinoShepherd's Avatar
    Join Date
    Mar 2005
    Location
    Portland, OR
    My Bikes
    Look, Niner, Ellsworth, Norco, Litespeed
    Posts
    1,415
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Rabbi -

    Oy vay!

    This reminds me of that goofy SunTour BMX freehub that was a two speed with a lever. The idea was a lower gear for the start, then when you release the lever it shifts into the higher gear. Neat idea for a question nobody asked.

    However, if your idea makes you happy, I say GO FOR IT! That's what building bikes is all about. Post pics too.

    -Z

  4. #4
    you can go backwards?!
    Join Date
    Jun 2005
    Posts
    390
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    WEIRD
    I had the EXACT SAME SET UP
    on the EXACT SAME BIKE
    earlier this winter, for the
    EXACT SAME HATRED OF SINGLEATOR
    (we have a bunch of broken ones around my shop)

    Now I'm back to 1x9 just because we had the parts and I needed a bike with gears to haul some stuff around on the trailer, but the two-speed manual was definitely a blast.

  5. #5
    The Rabbi seely's Avatar
    Join Date
    Apr 2004
    Posts
    4,864
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thats really funny--the Criss Cross seems to be a commonly *******ized bike. I imagine its because the geometry is really weird, and there are a million of them for free/cheap all the time. Not to mention the decent tire clearance. Mine was given to our shop, and an employee took it for his girlfriend, but since the geometry was so odd it didn't fit her. Thankfully, my geometry is odd! Right now its set up to be my winter/monster cross bike, so I'm trying to avoid shifters... had too much trouble with the 9spd setup so this seems to be a good compromise and uber reliable.
    commuter turned bike mechanic turned commuter (also a Velocity USA employee, but this is my personal account)

  6. #6
    you can go backwards?!
    Join Date
    Jun 2005
    Posts
    390
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    About the geometry and availability: I know, right? Mine fit the crazy 700x47 panaracer smokes we had at the shop on this mtb with kids function we helped out with when I rode with them. It feels just as comfortable to me with slicks going fast as it does with knobby's going moderately to extremely slow. and braze-on's galore!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •