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  1. #1
    Senior Member
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    '72 Schwinn Sports Tourer, '73 Schwinn Super Sport, '79 Schwinn Twinn Sport 10sp tandem
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    Progress on Schwinn Twinn Sport 10sp tandem

    So far so good. The bike is nearing its final stages, for me anyway. There's a limit to how much you can improve a low-end bike like this, and I'm rapidly reaching it. It's already a better bike than its captain is a rider. The bike has gone from 52 pounds to 47. Maybe I should quit while I'm ahead.

    Probably the only remaining change to make: Putting on the Shimano Megarange 13-34 freewheel when it gets here from halfway around the world.

    Before:


    .

    After:

    .

    .
    Last edited by Little-Acorn; 05-24-08 at 05:07 PM.
    '72 Schwinn Sports Tourer, original except for seat and 116psi tires
    48V 1000W black unbanded rear hubmotor kit from YXM Corp, 48V 20Ah LiFePO4 batt
    '79 Schwinn Twinn Sport 10sp tandem, 47#, now 14-speed with 12/34, aero wheels
    '07 Trek 7700 hybrid, 27sp, 20" frame, Conti UltraSport 700Cx28 116# tires, sweet
    '04 Trek 7500 hybrid, 17.5" frame, soon to be 48V 1000W rear-hubmotor electric bike

  2. #2
    Senior Member zonatandem's Avatar
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    ariZona carbon fiber tandem & single
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    . . .cut off that kickstand and you could knock off about another pound?

  3. #3
    Senior Member
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    The kickstand is one of the reasons I like Schwinns. I don't just ride them, I have to park them too, in diverse places and often for long periods. Sure, it's a pound of weight, but it's a USEFUL pound. That's where I draw the line. Besides, it's the best-designed kickstand I've ever used on any bike. Even if it does hang down like that one does.
    '72 Schwinn Sports Tourer, original except for seat and 116psi tires
    48V 1000W black unbanded rear hubmotor kit from YXM Corp, 48V 20Ah LiFePO4 batt
    '79 Schwinn Twinn Sport 10sp tandem, 47#, now 14-speed with 12/34, aero wheels
    '07 Trek 7700 hybrid, 27sp, 20" frame, Conti UltraSport 700Cx28 116# tires, sweet
    '04 Trek 7500 hybrid, 17.5" frame, soon to be 48V 1000W rear-hubmotor electric bike

  4. #4
    Senior Member
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    I decided to go with a 13-32 eight-speed freewheel for its smooth gear range (13-15-17-19-21-24-28-32) and versatility, and change the front smaller chainring from a 39-tooth to a 34-tooth to get that low gear back. With this combination (34 in front to 32 in back), I'll actually have a lower gear than the 39-to-34 combo it used to have. This freewheel is also dazzlingly shiny chrome-plated all over - the first bike bling I've ever put on a real bike.

    And with the 52 large chainring in front and the 13 in back, man this thing FLIES down hills. Especially with my 250-pound posterior on the captain's saddle. My 9-year-old stoker loves every minute of it.

    Now I'm going to have to get some 40-spoke or 48-spoke wheels for this thing (presently 36-spoke, not enough?), before I kill both of us. I'm watching the spoke tension like a hawk, having had a very bad experience with loose spokes and a steep hill on a JC Higgins in my childhood... when I was about the age my stoker is now. My predictions of "gentle riding around the park" are proving VERY inaccurate... ulp!
    Last edited by Little-Acorn; 05-28-08 at 02:09 PM.
    '72 Schwinn Sports Tourer, original except for seat and 116psi tires
    48V 1000W black unbanded rear hubmotor kit from YXM Corp, 48V 20Ah LiFePO4 batt
    '79 Schwinn Twinn Sport 10sp tandem, 47#, now 14-speed with 12/34, aero wheels
    '07 Trek 7700 hybrid, 27sp, 20" frame, Conti UltraSport 700Cx28 116# tires, sweet
    '04 Trek 7500 hybrid, 17.5" frame, soon to be 48V 1000W rear-hubmotor electric bike

  5. #5
    Senior Member
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    Specialized Rock Hopper, Felt F-70, lemond Buenos Aires, Trek T900 Tandem, Bianchi Volpe
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    I have really enjoyed seeing the progress on your Schwinn. It looks great--Thanks for sharing!

    Steve

  6. #6
    Senior Member
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    I had an eye on a 12-32 8-speed freewheel on Ebay, figuring that was the best I'd be able to do. 34-tooth largest cogs seem nearly nonexistent except for those silly Megaranges. And after running out of gears with the current 13-32 8sp freewheel on a screaming downhill, I really wanted to at least get a slightly higher top gear for those long downhills. I figured 12 teeth was the smallest I'd be able to find in ANY freewheel - have to go to a freehub and cassette to do any better, which I didn't really feel like doing.

    Was about to bid on the 12-32 8sp, when up popped a 12-34 7-speed freewheel a ways below it. it's a 12-14-16-18-21-26-34. Has ALL the high gears I want, and a slightly more rational path to the low gear.

    The seller had indicated a Buy It Now price. It's now on the way. :^) And I guess I'll have to modify my .sig below, to 14-speed soon.

    I'm also looking at resurrecting an old child seat for bicycles, that my now-19-yr-old son once sat in when he was two. It's one of those plastic things that mounts over the rear wheel on three struts. Not a bolt-on tandem wheel or a trailer. My other son (now two) might enjoy it.

    The Schwinn tandem may soon be the family triple. No, no usage of the 12-tooth cog is planned when the third seat is occupied >:-O
    '72 Schwinn Sports Tourer, original except for seat and 116psi tires
    48V 1000W black unbanded rear hubmotor kit from YXM Corp, 48V 20Ah LiFePO4 batt
    '79 Schwinn Twinn Sport 10sp tandem, 47#, now 14-speed with 12/34, aero wheels
    '07 Trek 7700 hybrid, 27sp, 20" frame, Conti UltraSport 700Cx28 116# tires, sweet
    '04 Trek 7500 hybrid, 17.5" frame, soon to be 48V 1000W rear-hubmotor electric bike

  7. #7
    Senior Member Retro Grouch's Avatar
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    What are you using for a rear brake?

  8. #8
    Senior Member
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    Quote Originally Posted by Retro Grouch View Post
    What are you using for a rear brake?
    A basic caliper. But the way we've been going down some of the hills here, I may re-string the Atom drum brake hub the bike came with with new spokes and and alloy rim and put it back on.

    I originally intended this bike for low-and-slow rides around the park. But my stoker has other ideas, so eventually new wheels and a drag brake (as above) may be in order.
    '72 Schwinn Sports Tourer, original except for seat and 116psi tires
    48V 1000W black unbanded rear hubmotor kit from YXM Corp, 48V 20Ah LiFePO4 batt
    '79 Schwinn Twinn Sport 10sp tandem, 47#, now 14-speed with 12/34, aero wheels
    '07 Trek 7700 hybrid, 27sp, 20" frame, Conti UltraSport 700Cx28 116# tires, sweet
    '04 Trek 7500 hybrid, 17.5" frame, soon to be 48V 1000W rear-hubmotor electric bike

  9. #9
    Live Everyday
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    "I originally intended this bike for low-and-slow rides around the park. But my stoker has other ideas, so eventually new wheels and a drag brake (as above) may be in order"

    Better hurry on these upgrades or forget them completely.....because......I see a new tandem in your future!!!
    Have fun

    Bill J.

  10. #10
    Senior Member
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    Quote Originally Posted by specbill View Post
    "I originally intended this bike for low-and-slow rides around the park. But my stoker has other ideas, so eventually new wheels and a drag brake (as above) may be in order"

    Better hurry on these upgrades or forget them completely.....because......I see a new tandem in your future!!!
    Have fun

    Bill J.
    Well, my stoker is only 10 years old, so I still have 51% of the vote. But it's a weak plurality at best.
    '72 Schwinn Sports Tourer, original except for seat and 116psi tires
    48V 1000W black unbanded rear hubmotor kit from YXM Corp, 48V 20Ah LiFePO4 batt
    '79 Schwinn Twinn Sport 10sp tandem, 47#, now 14-speed with 12/34, aero wheels
    '07 Trek 7700 hybrid, 27sp, 20" frame, Conti UltraSport 700Cx28 116# tires, sweet
    '04 Trek 7500 hybrid, 17.5" frame, soon to be 48V 1000W rear-hubmotor electric bike

  11. #11
    Senior Member
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    My leg strength isn't what it used to be, so the only reason I have to put anything on my tandem's rear smaller than 14 is to go downhill fast. OTOH, going up hills has to be a study in patience for me. But I did run out of gears with the current 13-32 freewheel, going down a long hill on a bike path near my house. Disappointed both me and my 10-year-old stoker son - the pedals was a-whizzin, but we couldn't go no faster. So I started looking for a 12-tooth smallest cog, pretty rare among freewheels.

    Other part of the story, is that I wanted a BIG cog for going the other way, up those hills. Turns out to be almost impossible to find a stoker's chainwheel smaller than the 39-tooth POS Sakae the bike came with (118mm BCD, yuck). So now two freewheels are on the way: A 12-34 7sp, and a 14-38 (yes, 38) 5sp for experimental purposes. The 5sp might wind up on my Super Sport, we'll see. But if I run out of gears with that 12-tooth on the rear, I probably didn't want to go that fast anyway.

    The 7sp is 12-14-16-18-21-26-34, and the 5sp is 14-17-22-28-38. Not much smooth shifting available from that 5sp with such big gaps, if I can find a derailleur to handle it at all, but if I can't get up a hill with that, then I'm better off walking anyway.

    A set of aerodynamic (sort of) tandem wheels is also on the way.
    '72 Schwinn Sports Tourer, original except for seat and 116psi tires
    48V 1000W black unbanded rear hubmotor kit from YXM Corp, 48V 20Ah LiFePO4 batt
    '79 Schwinn Twinn Sport 10sp tandem, 47#, now 14-speed with 12/34, aero wheels
    '07 Trek 7700 hybrid, 27sp, 20" frame, Conti UltraSport 700Cx28 116# tires, sweet
    '04 Trek 7500 hybrid, 17.5" frame, soon to be 48V 1000W rear-hubmotor electric bike

  12. #12
    Senior Member Retro Grouch's Avatar
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    Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
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    Quote Originally Posted by Little-Acorn View Post
    5sp is 14-17-22-28-38. Not much smooth shifting available from that 5sp with such big gaps, if I can find a derailleur to handle it at all, but if I can't get up a hill with that, then I'm better off walking anyway.
    Suntour Alpine Gear Tech derailleur is what you need. Good luck finding one. I know because that's what I eventually put on my Schwinn Twinn 25 or so years ago. I don't have it anymore.

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