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  1. #1
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    Duplicate gearing

    As a new biker I have been looking at duplicate gearing and wondering if there was a way
    besides only one front gear and say 10 rear gears to set up a bike and not have duplicates and over laping gears. The problem of chain angle and strain on the gears could be solved by having two front gears of the same size and shifting with the high 5 gears on one side and the low 5 on the other. Did I explain this right? some one in a previous post mentioned only using the center gears because of the angle and strain and shimano having a paten on a 14 gear rear sprocket.

  2. #2
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    A three ring set up gives you a gear range from 4:1 (44x11) to .65:1 (22x34). That's going to be hard to duplicate with just one ring up front. If you use a 44t only up front you would need a 68t cog to match the low gearing. If you used a 22t up front you would need a 6 tooth cog up front to match the high gearing. Your best option would be something in the middle, say a 32T. You'd still need a 8t cog for high gear and a 49t big cog for low gearing.


    Bottom line: some gears are duplicated in a multi-ring set up, that's the way it goes, get over it. Keep pedaling, have fun.
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  3. #3
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    Technically there are 28 gears, but that's just "technically". In reality you get three cogs in the rear for the granny up front, just about all the cogs for the middle chainring and the smallest three cogs for the big ring. Even this is subject to your particular chainline. And when you use the largest cogs or smallest ones while in the middle chainring, then your chainline will be off; you'll be wearing out your drivetrain.

    So is there a better way? If you just add gears to the cassette, then you will never have a good chainline--especially if you run only one chainring. The only solution is to cough up the grand for a Rohloff internally geared hub.

  4. #4
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    thank you for your answers. What got me thinking was looking at Sheldon Brown's
    gain ratio chart http://www.sheldonbrown.com/gears/ As you can see if you use 11-22-44
    up front and 8 rear gears (and I am not sure what I have on my bike) you have about 6 duplicate and or overlapping gears. Yes you are right and I should probably get over it and keep peddling, but I cant help but think there might be a better way. Shimano should be able to build a better way to shift if it were possible (and economically feasible) and unless they or a large company does i will have to live with what is available. Guyechka I will have to look up Rohlof and see what it is and how it works.

  5. #5
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    Quote Originally Posted by Fletch6
    thank you for your answers. What got me thinking was looking at Sheldon Brown's
    gain ratio chart http://www.sheldonbrown.com/gears/ As you can see if you use 11-22-44
    up front and 8 rear gears (and I am not sure what I have on my bike) you have about 6 duplicate and or overlapping gears. Yes you are right and I should probably get over it and keep peddling, but I cant help but think there might be a better way. Shimano should be able to build a better way to shift if it were possible (and economically feasible) and unless they or a large company does i will have to live with what is available. Guyechka I will have to look up Rohlof and see what it is and how it works.
    Well, your first problem is that you don't use 11-22-44 up front. You use 22-32-44. You still have some duplicated gears, again, that's the way it is. you want the gear range, you have to have multiple rings... blah, blah, blah...

    Rohlof is an internally geared hub. It is a different solution to gearing on bikes. As it is, internally geared hub and other derailleur-less solutions are expensive, heavy, don't have the range you need, innefficient or not strong enough. Or a combination of the above. The Rohloff is a good working piece of equipement, if you can afford it. I think it ain't light, though.

    Dude: get over it. If you don't need the lower or higher gearing you can run a 2x8, or even 1x8 (or 1x9) set up, If you want to have both top and bottom gear ========> three rigns and, oh, no! duplicate gearing. Which is not an issue since most of the "duplicate" combos (like 2:1 ratio) are not really usable. You can't, well, shouldn't use 22x11 or 44x22Now, 32x16 you can use.
    Art is the most intense mode of individualism that the world has known.

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  6. #6
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    FrozenK
    thanks for correcting my thinking about my front gears. As you can see I have a lot to learn.
    Yes the one question I have is to weight on the Rohlof. I was quite surprised when I plugged in Rohlof to Goggle and got Sheldon Browns page, because with all the looking at his gear ration charts I had not seen this referred to. He writes a very unbiased test report and I will have to study it more. there could be a weight mentioned somewhere.

  7. #7
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    Quote Originally Posted by Fletch6
    FrozenK
    thanks for correcting my thinking about my front gears. As you can see I have a lot to learn.
    Yes the one question I have is to weight on the Rohlof. I was quite surprised when I plugged in Rohlof to Goggle and got Sheldon Browns page, because with all the looking at his gear ration charts I had not seen this referred to. He writes a very unbiased test report and I will have to study it more. there could be a weight mentioned somewhere.
    We were having a discussion in another forum about Rohloff hubs and weight issues. One person changed from a regular drivetrain (I can't recall if it was XT or XTR or what, but it was standard lighter weight stuff) to a Rohloff hub. He gained a pound. Then again, he really likes it. I think they are about $1000 msrp, but some have found a little bit better deals. But you need to figure that you would be getting rid of shifters, derailleurs, cassette and two chainrings. That's a lot of money if it's XTR or X.0. And the thing about it is, you would never ever have to buy another cassette. The Rohloffs last forever.

    Your strange chainring set up has me wondering just what combo a person can still get away with without having trouble with the front derailleur. For instance, you could have a 20-32-44 or maybe a 22-34-46. You'd lose some cogs in the rear though.

  8. #8
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    From what I am reading about them I could get away with more because of my age and
    the fact I will never ride a bike as hard as the racers the units were engineered for.
    I did find a weight for the set up of 1730 gr. and a shipping weight of 5 lbs. My rockhopper has heavy and cheaper components than X0 or XTR and would probably be a plus especially if I got a good quality hollow crank on the front. It would however add the weight to the wheel where it would effect performance. I do live in Mass. and when I get over to Newton will stop at Browns to look and talk. Thanks again for your help and I hope some others got thinking about this subject.
    One of the things I was wondering about was if a single front gear could be engineered to move side ways when you shift the rear to keep the chain aligned perfectly with the rear cassette and would it be a benefit? This could be a better idea than my first post about two gears of the same size and a wide rear cassette.

  9. #9
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    44-22-11, Hmmm

    That would be an interesting crankset. I'm kinda tempted to set one up and give it a try, although finding a f derailleur to cover that range might be a problem. I've done 26 and 28T front differences and that's really pushing it so I'm thinking 33T front is almost out of the question.
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  10. #10
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    Quote Originally Posted by Fletch6
    From what I am reading about them I could get away with more because of my age and
    the fact I will never ride a bike as hard as the racers the units were engineered for.
    I did find a weight for the set up of 1730 gr. and a shipping weight of 5 lbs. My rockhopper has heavy and cheaper components than X0 or XTR and would probably be a plus especially if I got a good quality hollow crank on the front. It would however add the weight to the wheel where it would effect performance. I do live in Mass. and when I get over to Newton will stop at Browns to look and talk. Thanks again for your help and I hope some others got thinking about this subject.
    One of the things I was wondering about was if a single front gear could be engineered to move side ways when you shift the rear to keep the chain aligned perfectly with the rear cassette and would it be a benefit? This could be a better idea than my first post about two gears of the same size and a wide rear cassette.
    A sliding ring wouldn't be much of a benefit. You can't make it so it is aligned with the cog you are using all the time, it would be beyond hard to keep it adjusted. Second, that's an area that gets a lot of goo. Just what you want, getting the sliding arm covered in mud and dirt. It would wear out in five, four, three, two... And I guess that all the talk about gear range before, well...

    Again: you have some duplicated gears, get over it! the reason why the current system has been around so long is... that it... WORKS. Internally geared hubs and transmissions -a la GT DH rig- may even be a better solution. But, for now, the current system is a rather elegant solution.

    Matter of fact, if you don't like what your derailleurs do RIP THEM OFF!! I'm serious, I ride a singlespeed.

    Shayne: I really can't see the reason for having an 11t front ring. Are you looking at having some insanely low gearing???
    Art is the most intense mode of individualism that the world has known.

    Oscar Wilde

  11. #11
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    Quote Originally Posted by FrozenK

    Shayne: I really can't see the reason for having an 11t front ring. Are you looking at having some insanely low gearing???
    I dont get it either but the idea sounds interesting.

    24-28 is plenty low for me.

    EDIT: After looking at the Sheldon Brown calculator I think for experimental purposes I'd try 44-26-15 with a 11-23 cassette. Virtually 0 overlap although with an awkward shift pattern.
    Last edited by Shayne; 06-23-2006 at 11:01 AM.
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