Gears gears gear..what to choose?

Discussion in 'Cycling Equipment' started by bstephens, Feb 16, 2004.

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  1. bstephens

    bstephens New Member

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    Hello all...

    I am new to road cycling. I road a few thousand miles last year. I got a new bike about July last year. I did not know much about road bikes when I purchased it and I think the gearing my not be ther best for me.

    I am sure gearing is like favorite colors. Everybody has one and they are mostly different.

    I mostly wanted to talk about compact cranksets and what my riding will be like....

    I have a 13-29 now. Med cage derail. Standard size Front....

    Ok....It is an OK setup....not great but OK....


    The top two rear gears hit the top cog of the derail when I am in them. SO...here is my plan and here is the situation....


    I am getting a 12-25...I will ride that this year until July. I am going to France to ride a tour at Alp De Huez. I have been informed that there in no flat option. :)

    I am a so so rider....not a racer but I like to ride hard and think I am fast..... :)

    When I go to France I plan on getting a compact set of cranks. 50-34 and keeping my 12-25.....

    http://www.vsstech.net/biff/bike-gears.htm

    Here is a HTML file of my gear calc's

    I want to know what you guys think.....and I don't want to know about what a geek you think I am or that I have too much free time on my hands.....I have been bitten by the bug of road cycling. I like it. :)


    Here are a few other pic's of me and my bike..

    http://www.vsstech.net/biff/MS150.JPG

    http://www.vsstech.net/biff/my_ride.jpg

    http://www.vsstech.net/biff/hooters.jpg


    PS anyone going to be at the Jalapeno Hundred this weekend? http://www.harlingen.com/jalapeno.htm

    Me and my girlfriend will be. Let me know and we can say hi and maybe ride a few miles.....

    Biff
     
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  2. meb

    meb New Member

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    Deraileur jockey wheels hitting 29T sprockets is indicative of a deraileur adjustment problem, not a reason to change ratios. The trip to France might be a reason to change, but with no indication of where you are riding now and handling the hills, load you’ll be touring with, there is insufficient info on the ratio changes.

    For the derailleur, try this:

    http://www.sheldonbrown.com/derailer-adjustment.html

    See adjustment 4.
     
  3. bstephens

    bstephens New Member

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    Thank you for the quick reply.....

    I am in Oklahoma....will ride over Oklahoma, Arkansas, Texas and Kansas. Pretty flat but with some rolling hills. The lack of altitude breathing and mountain ride will effect me I am sure.

    Touring is a strong word and out of place really (sorry about that) We will be leaving from one location every day. We will be on an Alp though so the riding will be hard I am sure.....

    The second part:

    I have tried and tried......asked many times and mentioned each time I was NEAR a bike shop about the problem. My guess is that the bike.....a TCR Giant and not really made for such a big cassette. It would seem that the derail hanger would need to be just a bit longer. I have asked about this and there is not a longer one available.

    It has made the noise since the start of the bike and I really (I promise) have had more than a few bike shops look at it...they all say they can fix it and it is still there when I get it back...

    Hope this helps.......

    :)

    Biff
     
  4. meb

    meb New Member

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    The proposed ratio change has essentially the same bottom end as your current setup.
    That’s a lot of trouble to only save a few ounces in sprocket and chainring weight, particularly since the weight savings would be offset by the lower efficiency of the smaller sprockets.

    A longer cage might give you more clearance on the big sprockets, but since your angle of inclination is wrong, the resulting change would leave your derailleur excessively far away from small sprockets for smooth shifting. It would be a lot less effort to adjust the inclination adjust screw and have the derailleur work optimally on the large and small sprockets than replacing the arm and have the derailleur shift less smoothly.

    For the France trip-
    If in doubt, I’d want to have more climbing ability, so a lower gear ratio is in order.
    Changing front chainrings often leads to unexpected headaches with the front derailleur-at minimum you need some adjustment and/or positioning changes, might need a new front derailleur.

    Take a look at this thread:
    http://www.cyclingforums.com/t88848.html

    Or you might go with an 11/34 or 12/34 Megarange cassette.
    Better to have too low a bottom than too high.
    That would need a rear derailleur change to a long cage ratio. Mountain bike long cage derailleurs easily shift on that cassette. A long cage derailleur has more chainwrap takein/takeout than short or medium cage derailleur at the expense of shifting quality.
     
  5. As already mentioned, your rear derailleur is not in adjustment if it is hitting the cogs. Try
    turning the B screw in more, or all the way in. I am pretty sure turning the B screw in moves the
    derailleur pulleys farther away from the cogs. The B screw is the small screw on the back of the
    rear derailleur near the frame's derailleur hanger.

    As for your gearing, you currently have 39x29 as your low. 35.64 gear inches. (Formula is 39 divided
    by 29 times wheel diameter of 26.5 inches.) Assuming you have the 99.99% standard 39 tooth inner
    chainring. You propose changing your gearing to a low of 34x25.
    36.04 gear inches. And you are going to go ride up Alpe d'Huez. More power to you.

    Your high gear with 53x13 is 108.04 gear inches. Your proposed new high gear of 50x12 will be 110.42
    gear inches. I have no doubt you will be faster down the mountains in your higher gear.

    I'm curious how you concluded your current Campagnolo gear setup is not great but OK, while your new
    gear setup will presumably be great?

    stephens <[email protected]> wrote in message
    news:<[email protected]>...
    > Hello all...
    >
    > I am new to road cycling. I road a few thousand miles last year. I got a new bike about July last
    > year. I did not know much about road bikes when I purchased it and I think the gearing my not be
    > ther best for me.
    >
    > I am sure gearing is like favorite colors. Everybody has one and they are mostly different.
    >
    > I mostly wanted to talk about compact cranksets and what my riding will be like....
    >
    > I have a 13-29 now. Med cage derail. Standard size Front....
    >
    > Ok....It is an OK setup....not great but OK....
    >
    >
    > The top two rear gears hit the top cog of the derail when I am in them. SO...here is my plan and
    > here is the situation....
    >
    >
    > I am getting a 12-25...I will ride that this year until July. I am going to France to ride a tour
    > at Alp De Huez. I have been informed that there in no flat option. :)
    >
    > I am a so so rider....not a racer but I like to ride hard and think I am fast..... :)
    >
    > When I go to France I plan on getting a compact set of cranks. 50-34 and keeping my 12-25.....
    >
    > http://www.vsstech.net/biff/bike-gears.htm
    >
    > Here is a HTML file of my gear calc's
    >
    > I want to know what you guys think.....and I don't want to know about what a geek you think I am
    > or that I have too much free time on my hands.....I have been bitten by the bug of road cycling. I
    > like it. :)
    >
    >
    > Here are a few other pic's of me and my bike..
    >
    > http://www.vsstech.net/biff/MS150.JPG
    >
    > http://www.vsstech.net/biff/my_ride.jpg
    >
    > http://www.vsstech.net/biff/hooters.jpg
    >
    >
    > PS anyone going to be at the Jalapeno Hundred this weekend? http://www.harlingen.com/jalapeno.htm
    >
    > Me and my girlfriend will be. Let me know and we can say hi and maybe ride a few miles.....
    >
    > Biff
    >
    >
    >
    > --
     
  6. > Or you might go with an 11/34 or 12/34 Megarange cassette. Better to have too low a bottom than
    > too high. That would need a rear derailleur change to a long cage ratio. Mountain bike long cage
    > derailleurs easily shift on that cassette. A long cage derailleur has more chainwrap
    > takein/takeout than short or medium cage derailleur at the expense of shifting quality.

    He has Campagnolo if his 13-29 cassette statement was correct. With Campagnolo 13-29 is the
    Megarange cassette. And 13-29 is only available in 10 speed, so he cannot use a Shimano 9 speed
    cassette as a substitute for a Campagnolo 9 speed wheel, as some folks do. If he wants lower gears,
    he has to get lower chainrings on his crank. Triple could easily do that by just changing the crank,
    bottom bracket, and maybe front derailleur. $180 for Centaur 9 speed from Nashbar which will work
    just fine on a 10 speed bike because the crank, bottom bracket, and front deraillleur don't really
    care if its 9 or 10 speed.
     
  7. bstephens

    bstephens New Member

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    That is correct, it is a Record setup...sorr for the oversite..

    B
     
  8. > > Triple could easily do that by just changing
    > the crank, bottom bracket,
    > > and maybe front derailleur.
    >
    > Rear derailleur, too, since he would need a long cage.

    He has a Campagnolo medium cage rear derailleur already according to his statement. A medium cage
    rear derailleur will work just fine with a triple and a 29 rear cog. He does not need the slightly
    longer long cage rear derailleur. Unless he just wants to spend money for a new rear derailleur.
     
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