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  1. #1
    fair weather cyclist pjcampbell's Avatar
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    Stupid question about 1/8" chain on 3/32" gears

    Well I am an idiot - I bought a bike from BikesDirect and never bothered to check what they gave me. They told me 3/32" and I finally measured it (after buying 2 3/32" cogs and a 3/32 chainring) and both chain and DA 49t are 1/8".

    Question is how much trouble will I get in racing on a 1/8" chain on 3/32" gears, aside from some side to side slop...

  2. #2
    Senior Member bitingduck's Avatar
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    Generally fine. I have a random assortment of 1/8 and 3/32 cogs and chainrings and just use 1/8 chains. just check your chain tension and make sure you can't derail the chain with the side of a wrench.
    Track - the other off-road
    http://www.lavelodrome.org

  3. #3
    Elitist carleton's Avatar
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    I'd suggest buying 1/8" from here on out...unless you have a particular preference for 3/32". Most track-specific gear (cogs, chains, chainrings) comes in 1/8" with only a few manufacturers offering 3/32" as well. Plus it's easier to borrow stuff in a pinch if you are on 1/8". You can borrow 3/32" or 1/8".

    That being said, I know of a few people that are on 3/32 cogs, chainrings, and chains. I would assume that they have specific reasons for choosing them.

    I would assume that you bought the Motobocane Team Track (which is a nice bike). I would venture to guess that they chose to use 3/32" in the spec because they got 3/32" parts for less than 1/8" being that it's less popular which keeps the price down. But, that's all speculation. You are sort of lucky to get a 1/8" Dura Ace chainring.
    Last edited by carleton; 07-24-11 at 02:56 PM.

  4. #4
    Senior Member bitingduck's Avatar
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    Quote Originally Posted by carleton View Post
    That being said, I know of a few people that are on 3/32 cogs, chainrings, and chains. I would assume that they have specific reasons for choosing them.
    they're roadies?

    Modern 3/32 chains are nice if you have to live with a terrible chainline-- most of them are made to be used with geared bikes. 3/32 will be a tiny bit lighter, so in principle you can spin it up faster, but the difference is not likely to be noticeable by anyone. And like you say -using 1/8" chain means you can borrow rings and cogs from pretty much anybody. There's also no particular reason anymore to work hard to make your bike light-- it's pretty easy these days to end up under the 6.8 kg limit without going to any effort at all.
    Track - the other off-road
    http://www.lavelodrome.org

  5. #5
    fair weather cyclist pjcampbell's Avatar
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    OK I see what happened. They gave me a 1/8" chain with 1/8" 49t and 1/8" 15t, but told me it was 3/32" and then they threw in a DA 3/32" 16T cog too... very odd. So I ordered myself a 14t and a 51t in 3/32". I'll figure something out. Heh. Unfortunately my combinations for 1K and 3K this week both include either a 14t or a 51t. My main concern was whether this is going to cause any problems (chain falling off or something). I can see a little side to side slop.

  6. #6
    Elitist carleton's Avatar
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    Quote Originally Posted by bitingduck View Post
    they're roadies?
    Well there is this article about Sarah Hammer:


    Hammer rides with an Octalink SRM to record her performance. Like most endurance athletes she rides with a 3/32″ “road” pitch chain and chainring. Also noticeable is a large pedal washer on her Shimano SPD-SL pedal.
    http://velonews.competitor.com/2011/...march-2011-102

    I'm not sure I'd agree with the "Like most endurance athletes..." part. But, Casey Gibson would certainly know more than I would. He's seen more world-class bikes up close than many.

    Main article: http://velonews.competitor.com/2011/...elt-tk1_165893

    The others that come to mind were on the Cox Atlanta Velo team from the 90s or early 2000s. The 2 that I know of that are still racing use 3/32" because that's what their coach put them on. One is a male endurance track specialist. The other is a female all-around racer. Both national-level masters now.

  7. #7
    Elitist carleton's Avatar
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    Quote Originally Posted by pjcampbell View Post
    OK I see what happened. They gave me a 1/8" chain with 1/8" 49t and 1/8" 15t, but told me it was 3/32" and then they threw in a DA 3/32" 16T cog too... very odd. So I ordered myself a 14t and a 51t in 3/32". I'll figure something out. Heh. Unfortunately my combinations for 1K and 3K this week both include either a 14t or a 51t. My main concern was whether this is going to cause any problems (chain falling off or something). I can see a little side to side slop.
    Yeah, I can see the confusion caused by the specification of the bike.

    1) You will be fine racing 3/32" cog and chainring on a 1/8" chain.
    2) If you really want peace of mind, can you borrow a 51t and 14t from some friends or local trackies? (assuming that you are going to Masters Nationals this week)

  8. #8
    Senior Member bitingduck's Avatar
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    Quote Originally Posted by carleton View Post
    I'm not sure I'd agree with the "Like most endurance athletes..." part. But, Casey Gibson would certainly know more than I would. He's seen more world-class bikes up close than many.
    Interesting. Her locker was next to mine before they moved to switzerland, but I didn't know she was running 3/32.

    But I'd agree that the "most endurance athletes" is probably a bit of an overstatement.
    Track - the other off-road
    http://www.lavelodrome.org

  9. #9
    fair weather cyclist pjcampbell's Avatar
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    thanks... I think i'll be good. Seems a little sloppy side to side but otherwise OK. I will be there tomorrow and Wednesday. Good luck.

  10. #10
    Senior Member chas58's Avatar
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    On rare occasions doing something like a flying 200 I have heard of the chain coming off when running the thinner cog (slightly worse with steel frames). Some people strongly recommend against it, some say its no big deal. Obviously it is not optimum, but there is a very small risk of the chain coming off. Generally not too much of a safty issue, but it does take a while to come to a stop if you are doing over 30mph.

    Its not a stoopid question. ;-)

  11. #11
    Senior Member hamish5178's Avatar
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    This thread made me curious so I went and took a measuring tape to my Dura-Ace drivetrain which was originally on a Team Track. Mine is also 1/8th, but I've been running a 3/32 cog from the day I got the bike with no issues. This is good news, I can now buy the cool kid chains and cogs!
    Quote Originally Posted by hairnet View Post
    It's a fixie, reasonablility was never a factor.
    My poser bike

    my non-poser bike?

  12. #12
    Senior Member Brian Ratliff's Avatar
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    If your chainline isn't good, I'd highly suggest getting a 1/8th inch cog. I modified my track bike to do a single speed crit one time this year. The only SS freewheel that was available to me was for 3/32nds. My chainring and chain were 1/8th. Ended up dropping out of the crit when the chain came apart.

    Not the chain's fault; I had been using that chain at the velodrome for a while and it was in fine shape. I believe the chainline was off enough that on one revolution, the chain sideplate caught on the tip of one of the thin cog teeth and the pivot pin was dislodged. It was a bit scary; fortunately, when the chain broke, it came off cleanly and I didn't lose control of the bike.
    Cat 2 Track, Cat 3 Road.
    "If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter

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