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  1. #1
    Mad scientist w/a wrench
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    sorta single-speed (Damn this is fun)

    How many of these fg/single speed stories start with: So i've got this old frame with horizontal dropouts...

    and I do, (10speed american 70's steel roadbike) and modernizing it would be pointless (not to mention cost wayy more than its probably worth) so I thought I'd give single-speed and fixed gear a try.

    I doubt my legs are quite ready for the joys of fixed gear (but it just looks soo fun) so I jury-rigged the bike to single speed: (read, tore off the derailleurs and shortened the chain to fit the best available gear ratio/chainline) in my case, 52/20 (27" wheels and 165 crank...I used Sheldon Brown's gain ratio system and I think this works out to something sane)

    I took off for my morning commute (mostly rolling hills, maybe 2 500m flats on the whole 6.5 mile trip)
    I was expecting to huff and puff my way up the hills, maybe walk one of them, and proably be late to work.

    Instead I somehow made it 2 minutes ahead of my usual time and managed to make it up the hills a bit easier than I usually do.

    my one error: didn't tighten the rear axle well enough (and/or my chainline sucks) and had some rather odd chain derailment going on (the chain got stuck between the 52t chainwheel and this ornamental protector plate, while on the rear it just jumped down 2 sprockets. did I mention even with having to flip the bike, and fix this, I somehow made it to work earlier than usual?

    I think I'm going fixxie as soon as I can get some wheels with the right hubs ordered (if my rims weren't almost shot I'd think of rebuilding them)
    Proudly wearing kit that doesn't match my frame color (or itself) since 2006.

  2. #2
    SERENITY NOW!!! jyossarian's Avatar
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    You commute on something that probably weighed close to 25 lbs w/ working derailleurs and you don't think you're ready for a sub 20lb fixie? I'd say the only thing holding you back is the checkbook. Congrats and enjoy the bike.
    HHCMF - Take pride in your ability to amaze lesser mortals! - MikeR



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  3. #3
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    rear cogs are designed to shift not to be cranked on sans derailluer. thats why you have issues. the chain is trying to derail, thereby pulling the wheel off center, no matter how tight your nuts are. happens almost every time. you could have the worlds best chainline.... but rememeber, if its a freewheel, and i assume it is, just remove it, viola! you have the threads for a bmx freewheel, which costs maybe 20 bucks, is lighter and wont have the problem. thats the exact deal i put 20+ miles on (hilly) a day, and it doesnt budge, and i even use a QR on the wheel...

  4. #4
    Mad scientist w/a wrench
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    Quote Originally Posted by jyossarian
    You commute on something that probably weighed close to 25 lbs w/ working derailleurs and you don't think you're ready for a sub 20lb fixie? I'd say the only thing holding you back is the checkbook. Congrats and enjoy the bike.
    Haven't weighed the bike lately, but an old catalog puts it at 39. I'd say its stripped down to 30 (lighter tires, no derailleurs, eggbeater pedals instead of plastic junk and a fairly light saddle)

    being in an area with lots of hills, I mash quite a bit just to get up them and have to coast back down. its not climbing them that daunts me as much as spinning my way back down on already fatigued legs. Is that something I should be worried about?
    Proudly wearing kit that doesn't match my frame color (or itself) since 2006.

  5. #5
    aspiring dirtbag commuter max-a-mill's Avatar
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    Quote Originally Posted by krazygluon
    being in an area with lots of hills, I mash quite a bit just to get up them and have to coast back down. its not climbing them that daunts me as much as spinning my way back down on already fatigued legs. Is that something I should be worried about?
    i wouldn't worry unless your gonna go brakeless.

    you certainly won't go as fast as coasting down them will let you. after a couple days/weeks you learn to let your legs go limp and descending (with a brake) isn't really too bad. then after a few more weeks you might find yourself wanting to try to use your legs too keep your s[peed in check downhills. that hurts like hell (at least for me, so far, on bigger hills) but boy will it make you stronger...

    for a hilly commute i can't imagine fixed being as fast. but it sure is more entertaining than regular old singlespeeding.
    - the revolution will not be motorized -

  6. #6
    . bbattle's Avatar
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    Oh, the ornamental protector disk is aka "dork disk" and must be removed pronto lest someone photographs you and your bike and you end up the inspiration for another 80 pages of "I hate Everybody".

  7. #7
    Perineal Pressurized dobber's Avatar
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    Quote Originally Posted by ridelugs
    rear cogs are designed to shift not to be cranked on sans derailluer.
    Please explain this bit of misinformation.

    As for the OP's chain derailments, its most likely due to a poor chainline. From his description of a 52-20, it sounds like he's running the big ring up front and a fairly good sized cog in the cluster which would put it closer to the centerline of the wheel.

    Outside ring and inside cog, recipe for chain jump.
    This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.

  8. #8
    SERENITY NOW!!! jyossarian's Avatar
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    +1 to what max-a-mill said about going downhills. You should definitely run a front brake on a fixie. And depending on the conditions (light to no traffic w/ no intersections or driveways), you can fixie coast. Take your feet off the pedals and rest them on the chainstays or downtube. I prefer the chainstays. Just don't let your heels foul up the chain or spokes or you'll be sorry. And you should definitely have a front brake for that maneuver.
    HHCMF - Take pride in your ability to amaze lesser mortals! - MikeR



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  9. #9
    Senior Member
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    Please explain this bit of misinformation.

    As for the OP's chain derailments, its most likely due to a poor chainline. From his description of a 52-20, it sounds like he's running the big ring up front and a fairly good sized cog in the cluster which would put it closer to the centerline of the wheel.

    Outside ring and inside cog, recipe for chain jump.

    explain what bit of misinformation? if you take a perfectly good chainline, for example: a spot singlespeed with a king rear hub, and install a ramped rear cog on it, it WILL throw the chain. likewise even if you have dead on chainline and a geared cluster in the rear, thats newer than say, 1932, you will throw the chain, maybe not every ride, but its simply an inevitability. I say this as the past owner of many such rigs, and the current owner of many perfectly fuctional single speeds. also, let it be known that if you have a non ramped cog in the back, ie an ACS freewheel, and a non ramped ring in the front, you can run a ****ty chainline and not throw a chain, or dislodge your rear wheel, but you do however wear everything down quicker, with more possibility of a broken part.

  10. #10
    Mad scientist w/a wrench
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    This cassette isn't ramped. I suspect the chainthrow had more to do with my slightly bent dork-disk which has given me shifting problems in the past. as best I can recall, I was standing pedalling starting to go up a hill hill when all of a sudden the chain skipped and got a lot EASIER to pedal when the chain jumped off the 52t chainring down to my 39 inner. then after trying to pedal some more, it skipped again and got harder (the 20t cog is the center of the 5 cog cluster) as it jumped down to my 14, then finally it became impossible (because the inner chainring/outer cog combination paired with a lack of derailler tried to shift back up to the 52t but overshot it and rode the gap between the 52 and the dork disk, thus jamming the chain.) another bit of evidence toward this is that my chainline errs toward either going to a bigger cog or the smaller chainring, not in the direction of the dork disk, despite that somehow being where I wound up.

    somehow this is beginning to sound like a magic bullet argument, but that's the best of what I can remember
    Proudly wearing kit that doesn't match my frame color (or itself) since 2006.

  11. #11
    Perineal Pressurized dobber's Avatar
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    Quote Originally Posted by ridelugs
    explain what bit of misinformation? if you take a perfectly good chainline, for example: a spot singlespeed with a king rear hub, and install a ramped rear cog on it, it WILL throw the chain.
    Horse hockey.
    This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.

  12. #12
    slot machine
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    400 dollars and a good eye for ebay and craigslist will get you on a roadworthy track/fixed gear bike. save up to buy one, and keep the old junky ss, an ss. word.
    love your friends... die laughing.

    velospace

  13. #13
    Senior Member john_and_off's Avatar
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    i wouldn't be so bold as to say my situation is applicable to everyone else, but just to put this out there, i have a loaner/beater bike which i single-speeded in the same fashion as the OP (removed the derailleur/shifters and shortened the chain), and i've never once thrown the chain, nor has my dear friend who's had the bike on loan for several weeks.

    for the record, the chainline is pretty good...

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