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  1. #1
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    So now the question is gearing

    On the good advice of this forum we placed our order for a Co-Motion Mocha, with 26" wheels, Tropical Green (I resisted putting up a poll for the color). Until delivery in May I have a little time for last minute tweeking and options. This forum is great, answers keep on comming, hope to be able ta pay back some day, though I have been able to cotribute a little.

    So now the question is gearing.

    So far the order is for:
    52-39-28 chain rings , and 11-34 10sp IRD Cassette with Shimmano Ultegra STI shifters

    1. 28/34 seems awfully low, particularly on 26" wheels no?, and I do get to 54/11 on my single infrequently, so shouldn't we have a 54/11 on the tandem? My gut says 54-30 / 11-34 . So go with my gut or listen to the shop's advice. Or go half way 54-28 on the chainrings?. I believe I have 54-30 / 11-28 on our current tandem, and have not seen a hill we could not tackle, admittedly we have never done the steepest of hills with a fully loaded bike.

    2. Going back to a question previously posted, 10 speed cassette or 9 speed in order to have less trouble finding chains? This question was asked in New bike 10 speed or 9 speed ultegra? I guess I better go ask my LBS if they have any 10 speed chains.

    Bike will hopefully see loaded touring on mountain terrain, but sees a lot of flat land around Buenos Aires, and rolling hills across the river in Uruguay. 310 lbs team, 4000 km/yr, not the most powerful of teams, but we can pull our weight.

  2. #2
    hors category TandemGeek's Avatar
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    Build a gear table and figure it out. There are several free caculators on line to assist you.

    http://sheldonbrown.com/gears/
    http://www.bicyclesource.com/bike/ge...avascript.html
    http://home.earthlink.net/~mike.sherman/shift.html

    If you know how to use a spreadsheet program like Excel you can quickly build a spreadsheet to analyze the the different options side-by-side. You can make your spreadsheets as simple or complex as you like. The one in the attached .jpg took about 3 minutes, whereas the ones I did for myself to evaluate compact drive configurations was a bit more over-the-top: http://www.thetandemlink.com/gearing.html
    .
    Attached Images Attached Images
    Last edited by TandemGeek; 02-23-07 at 07:06 AM.

  3. #3
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    I can't give advise on gear ratios, wheel sizes, crank lengths, etc.... I do not remember what I have on my own rigs. But from our experience:

    -Chain rings, chains and cassettes are parts that you will find yourself replacing often. I doubt that you will be only riding 4000 km/year once you get your new rig.

    -We have more than one cassette that we switch for especial rides.

    -You can use 10 sp chain on a 9-speed cassette. Don't know if vice versa??

    -We can spin OK at a max of 120 RPM so we can develop 41 MPH... very close to the top speed that my wife feels comfortable at.

    -We rather limit our top speed downhill than having a hard time going uphill. Knees on one piece at the end of the climb, and a happy stoker, are much more valuable than a few seconds difference in a long down hill.

    - It never bother us before, but as we age, small jumps between gears are greatly appreciated.

  4. #4
    hors category TandemGeek's Avatar
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    Quote Originally Posted by cornucopia72
    -You can use 10 sp chain on a 9-speed cassette. Don't know if vice versa??
    You can use Shimano's very narrow 9 speed chains on Campy 10 speed, but Shimano 10 speed requires a 10 speed chain.

  5. #5
    Time for a change. stapfam's Avatar
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    Quote Originally Posted by Xanti Andia
    So now the question is gearing.

    So far the order is for:
    52-39-28 chain rings , and 11-34 10sp IRD Cassette with Shimmano Ultegra STI shifters

    1. 28/34 seems awfully low, particularly on 26" wheels no?, and I do get to 54/11 on my single infrequently, so shouldn't we have a 54/11 on the tandem? My gut says 54-30 / 11-34 . So go with my gut or listen to the shop's advice. Or go half way 54-28 on the chainrings?. I believe I have 54-30 / 11-28 on our current tandem, and have not seen a hill we could not tackle, admittedly we have never done the steepest of hills with a fully loaded bike.

    2. Going back to a question previously posted, 10 speed cassette or 9 speed in order to have less trouble finding chains? This question was asked in New bike 10 speed or 9 speed ultegra? I guess I better go ask my LBS if they have any 10 speed chains.

    Bike will hopefully see loaded touring on mountain terrain, but sees a lot of flat land around Buenos Aires, and rolling hills across the river in Uruguay. 310 lbs team, 4000 km/yr, not the most powerful of teams, but we can pull our weight.
    My set up is 48/36/24 with an 11/32 cassette on 26" wheels with 26x1.4 slicks for road use.

    Mountain terrain and I would say 28/34 is not low enough. I know I ride offroad but 26/32 was too high. Warning here- I tried a 12/34 cassette in XT grade and bent it SO- I stayed with 11/32 in LX and was fine. I then changed the granny ring to a 24 and I am happy with that. That is offroad but onroad it is surprising how often we get into 24/32 and need it. On the top end I have a 48. 48/11 at a cadence of 100 is 30mph. Much faster than that and we will be coasting downhill.

    If we were to road ride more often- then I would be loath to change our gearing. If I was on flatter routes then I may go up to a 50 but I doubt that we would pull that high a gear that often. In fact most of our speed riding on the flat is 48/13or 14

    On 10 or 9 speed. I am 9 speed and don't break many chains but even then I go to a stronger XT grade chain as I have broken Dure-ace chains (Dure-ace is supposedly better quality but it does not stand up to our use) I have heard of several Solo riders that break 10 speed chains frequently.
    How long was I in the army? Five foot seven.


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  6. #6
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    You may get as many different opinions of gearing as you do responces. Each person has a different preference... differing fitness levels and are riding in different terrain.

    At the shop where I work... we will have new college students come in.. or tourist... some will say man! it is hilly here... and others ask... where are all the hills? It really depends on where they came from.

    I have no idea how available 10sp "stuff" is in your area... but I was very surprised to hear in an earlier thread of people having difficulties in finding chains in Oregon.

    Where you have experince from your previous bike, and your single bike... I would use that as something of a guideline.

    I do not do loaded touring..but my previous bike I used as a double..the stock gearing was a 54 -44- and the unused might have been a 30. I run a 11-28 on it. [it was 8 sp]. My new bike a 10sp has a 55-42.. again a double. I have used it with the 11 -34 that it came with.. but find the jumps at the high gear end...to big.... it is too far apart from gear to gear. So we are putting an II-28 on it.

    The older bike is being converted over to 10 speed. that I will put on the 11-34.. and may set it back up as a triple. This is our early season bike.. when the roads are crappy.. and we have less road fitness.

    as has been stated... short of the 10sp vs 9sp question... the rest is pretty easy to change. You could also do as some do.. switch cass. Use a tighter cass. for your regular riding, and something like an 11-34 when you are touring.

    glenn

  7. #7
    Senior Member zonatandem's Avatar
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    52x11 on 26" wheels = 122.9" gear
    54x11 " " " = 127.6" gear

    28x34=21.5"gear
    30x28=27.8" gear

    Depending on your team's preferences/capabilities/terrain/touring load a 127.6" gear seems to be a bit much.
    We've used 120" on nice downhills, but heck, you can also coast and take a breather!
    A 28x34 super-granny seems low, but again depending on your needs, like perhaps climbing the Andes fully loaded . . .
    You can coast down a hill but you've got to pedal UP! So our motto with granny gearing is that's it's better to have it and not need it, than to need it and not have it!
    On the question of 9 or 10 speed cassette, the availability of chains at your LBS in Bueno Aires will guide you on that.
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  8. #8
    hors category TandemGeek's Avatar
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    Quote Originally Posted by zonatandem
    52x11 on 26" wheels = 122.9" gear
    54x11 " " " = 127.6" gear

    28x34=21.5"gear
    30x28=27.8" gear
    That would be on a bike with 26" wheels running 38mm tires, Yes?

  9. #9
    Elite Rider Hermes's Avatar
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    We have 53/39/30 with a 10 sp 11/34.

    We had some 2004 Catena Zapata Malbec wine last week. It was fantastic!

  10. #10
    Senior Member zonatandem's Avatar
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    Whether you're running wide/medium/narrow tires will make a small difference in the actual gear inches.

  11. #11
    hors category TandemGeek's Avatar
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    Quote Originally Posted by zonatandem
    Whether you're running wide/medium/narrow tires will make a small difference in the actual gear inches.
    Yeah, a difference of about 5% in this example, which is why it's a pretty good idea to specify the tire size used in making the calculations:

    52x11 on 26" wheels w/38mm wide tire = 122.9" gear inches
    52x11 on 26" wheels w/28mm wide tire = 116.8" gear inches

    54x11 on 26" wheels w/38mm wide tire = 127.6" gear inches
    52x11 on 26" wheels w/28mm wide tire = 121.3" gear inches

    28x34 on 26" wheels w/38mm wide tire = 21.5" gear inches
    28x34 on 26" wheels w/28mm wide tire = 20.3" gear inches

    30x28 on 26" wheels w/38mm wide tire = 27.8" gear inches
    30x28 on 26" wheels w/28mm wide tire = 26.5" gear inches

  12. #12
    Senior Member zonatandem's Avatar
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    Xanti did not specify tire width but did mention loaded touring/off road terrain as well as road riding.
    Logically, for touring/off road a wider tire can/will be used than road riding.

  13. #13
    Senior Member
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    Quote Originally Posted by lordoftherings
    We have 53/39/30 with a 10 sp 11/34.

    We had some 2004 Catena Zapata Malbec wine last week. It was fantastic!
    Good people the Catenas they make great wines, and they have developed the wine export business better than any other Argentine winery. For another great wine, pricey but actually cheaper for you than it is for us here in Argentina, check out Achaval Ferrer.

    Checked with a couple of LBS and the 10 sp chains are generally available here. Only question is their reliability on a tour, but I have not heard major complaints from any of you. And I have the answer on gearing. I'll stick to 52-39-28 chain rings , and 11-34 10sp, and if it turns out I want somehting else for my unloaded riding, I'll switch the cassette.

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