Junior Gearing Front DR Question
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  1. #1
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    Junior Gearing Front DR Question

    All. So I did some digging on this to no avail. I am trying to find out if someone makes a front BRAZE on Dr. that will work with smaller chainrings to try and accomplish Jr. gearing help out of the front chainrings. Here is our setup.

    My son is on a Specialized Allez Sprint with a welded braze on mount. He is running a 36/50 front Chainring setup. Right now his Dr is a braze on Tiagra that is working but the spacing is simply way off and it is not working properly. Believe it or not, I drilled and tapped a new mounting hole in the Dr. It is way better but simply not right.

    Can someone recommend a front Dr. for a welded Braze on that does in fact have the reach. Thinking a triple might be my only alternative but even then I have concerns about the top end. Thanks.

  2. #2
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    50/36? Or smaller than that...you're not clear what rings you want to use. Any front derailleur should work, if it doesn't it's the location of the braze-on mount not the derailleur that's the problem.
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  3. #3
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    CXwrench. You are correct about the location of the braze-on. That is absolutely the issue. this frame was welded for a 53. That said, I know Wickworks makes an adaptor for this very issue, but it is pricy.

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    I'm sure it's very well made...if Mark will use their chainrings on Katie Compton's bikes they must be good.
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  6. #6
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    Quote Originally Posted by Rmabus View Post
    All. So I did some digging on this to no avail. I am trying to find out if someone makes a front BRAZE on Dr. that will work with smaller chainrings to try and accomplish Jr. gearing help out of the front chainrings. Here is our setup.

    My son is on a Specialized Allez Sprint with a welded braze on mount. He is running a 36/50 front Chainring setup. Right now his Dr is a braze on Tiagra that is working but the spacing is simply way off and it is not working properly. Believe it or not, I drilled and tapped a new mounting hole in the Dr. It is way better but simply not right.

    Can someone recommend a front Dr. for a welded Braze on that does in fact have the reach. Thinking a triple might be my only alternative but even then I have concerns about the top end. Thanks.
    What happened to 14-28 freewheels? Put the 52-39 back on and get a junior rear cluster, 14-25, 14-27, 28. Your son will thank you!

    Junor gearing is limited to 52-14 or 97.57 gear inches. 50-13 is 101.25 gear inches, too high. The next lower gear would be 50-14, a puny 93.89 gear inches. Be nice to your son. Give him the full monty, 52-14. He's got plenty of gears left to perfect his spin.

    50-11 is a whopping 119.66 gear inches. That's insane. He'll never use the 11 or 12. If he uses the 50-13, he'll be cheating by 4 gear inches. Give him what he needs.
    Last edited by Fredrico; 3 Weeks Ago at 08:23 PM.

  7. #7
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    Quote Originally Posted by No Time Toulouse View Post
    Why are you posting this? It doesn't have anything to do w/ what the OP needs to do.

    Quote Originally Posted by Fredrico View Post
    What happened to 14-28 freewheels? Put the 52-39 back on and get a junior rear cluster, 14-25, 14-27, 28. Your son will thank you!

    Junor gearing is limited to 52-14 or 97.57 gear inches. 50-13 is 101.25 gear inches, too high. The next lower gear would be 50-14, a puny 93.89 gear inches. Be nice to your son. Give him the full monty, 52-14. He's got plenty of gears left to perfect his spin.

    50-11 is a whopping 119.66 gear inches. That's insane. He'll never use the 11 or 12. If he uses the 50-13, he'll be cheating by 4 gear inches. Give him what he needs.
    You suck at math.

    52/14=100.28
    50/13=103.84
    50/14=96.42
    50/11=122.72
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    Quote Originally Posted by cxwrench View Post
    Why are you posting this? It doesn't have anything to do w/ what the OP needs to do.



    You suck at math.

    52/14=100.28
    50/13=103.84
    50/14=96.42
    50/11=122.72
    I entered 700 x 23 tires at BikeCalc.com!

    The relationships are the same. The kid will still covet a 52 if he's competitive. And the 14 cog still stands as the highest gear a junior is allowed to race on. 50/13 is too high. He'll get his leg speeds up great on 52/14. Ask me how I know!

    Junior then only has to switch freewheels when he goes Cat. IV.

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    Quote Originally Posted by cxwrench View Post
    Why are you posting this?
    The bike was set up for 53-52 t. chainrings. Can't believe the braze-on hanger is mounted too high for the derailleur to reach a 50 t. ring. But if it is, rather than trying to jury rig the front derailleur hanger, the alternative would be a 14-25 to 28 rear cog cluster. Problem solved.

    This is entirely relevant to the discussion.

  10. #10
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    Sugino also makes an adapter, but I don't know how the price compares to the Wickwerks.

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    Quote Originally Posted by cxwrench View Post
    You suck at math.

    52/14=100.28
    50/13=103.84
    50/14=96.42
    50/11=122.72
    Those values are for a 27 inch wheel. A 700c wheel has a smaller diameter and probably results in the values given by Bikecalc.

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    Quote Originally Posted by cxwrench View Post
    Why are you posting this? It doesn't have anything to do w/ what the OP needs to do.



    You suck at math.

    52/14=100.28
    50/13=103.84
    50/14=96.42
    50/11=122.72
    For a 700c 23mm tire, those numbers are about 2.85 % high. Not sure if the officials take tire size into account. I've seen them do rollouts, but that was many years ago. Back then I heard stories about kids getting in trouble if they had fatter tires and were pushing very close to the rollout limits.

  13. #13
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    Quote Originally Posted by Fredrico View Post
    The bike was set up for 53-52 t. chainrings. Can't believe the braze-on hanger is mounted too high for the derailleur to reach a 50 t. ring. But if it is, rather than trying to jury rig the front derailleur hanger, the alternative would be a 14-25 to 28 rear cog cluster. Problem solved.

    This is entirely relevant to the discussion.
    No, I wasn't quoting you at that point, I was talking about the link that NTT posted for the 3* SRAM front derailleur shim. And there are plenty of bikes out there that have the front derailleur braze-on mount too high to work properly w/ a 50.

    As for gear inches the method that's been used forever for both road and track gearing is (chainring) x 27 by (cog)...so 50 x 27 15 = 90. Everyone that races on the track knows that 50/15 is a 90 inch gear.
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  14. #14
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    Quote Originally Posted by Rmabus View Post
    CXwrench. You are correct about the location of the braze-on. That is absolutely the issue. this frame was welded for a 53. That said, I know Wickworks makes an adaptor for this very issue, but it is pricy.
    I just saw this, IRD has an adapter for $30 which isn't as pricey as the WickWerks or the Sugino I posted earlier.

    https://store.interlocracing.com/irddedrad.html
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  15. #15
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    Dr = doctor

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  16. #16
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    Quote Originally Posted by ogre View Post
    Those values are for a 27 inch wheel. A 700c wheel has a smaller diameter and probably results in the values given by Bikecalc.
    Close enough for World Cup track racers...on bikecalc.com 50/15 w/ a 23mm tire is 87.xx, every track racer in the world knows that 50/15 is a 90" gear.
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  17. #17
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    Not sure if they still do rollouts, or if they just count the teeth? If they do rollouts, a 52x14 might work with a 23mm tire (or better yet a 22mm tubular). If they don't do rollouts, do they still allow "blocked" gears in non-national events??
    Just checked, and it looks like rollouts are still used.....Junior rollout is 26 feet. (7.93m)
    A 23mm tire should work.
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