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Re: [Geared_hub_bikes] Long Tail Bike Question?

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  • Dave Lloyd
    I ve got an Xtracycle, but it has a 3x8 standard mountain drivetrain. I have heard of people using a Nexus/Alfine on the rear, also a Nuvinci and Rohloff.
    Message 1 of 6 , Jan 11, 2010
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      I've got an Xtracycle, but it has a 3x8 standard mountain drivetrain.  I have heard of people using a Nexus/Alfine on the rear, also a Nuvinci and Rohloff.  All three seem to work relatively well.  Keep in mind that the Nexus is what's spec'd on a Bakfiets, so I think your issue is likely input torque and gear ratios rather than weight.

      I have to say, though, if you have any hills and you haul cargo (a grocery run can be around 80 lbs if you get a few gallons of milk, beer, etc.), you may want to skip the internal gears unless you can go with the Rohloff.  Most of the time I'm in the middle chainring up front, even when I'm hauling two kids, but boy that granny is nice when I need it. I think that if you don't have the extra wide range that a mountain derailleur based drivetrain gives you, you'll end up limiting your loads. 

      I'd also ask this question on the rootsradicals Yahoo group, which is the owners group for Xtracycles.

      --dlloyd



      On Mon, Jan 11, 2010 at 12:41, Rich <astronut1001@...> wrote:
       

      Have any members bought or assembled a long tail cargo bike such as the Xtracycle, Surly Big Dummy, Kona Ute or Yuba Mundo? How are they to use and ride with the extended wheelbase?

      I am considering one of the above. I note that the Surly literature states that the frame was designed to work with the OEM2 version of the Rokloff hub, in combination with a chain tensioner, though initially I would probably go with a non IGH drivetrain.

      My concern would be that any IGH other than the Rohloff might not handle the potential weight as none are rated for the service and the SRAM hubs specificallly state that they are not suitable for cargo bike service. Per some reports the NuVinci might stand up to such use.

      Rich Wood


    • Bruce Alan Wilson
      I have a Big Dummy with a Rolhoff and love it. Bruce Alan Wilson http://www.wvdemolay.org/ http://tinyurl.com/WVMSRideBAW The bicycle is the most civilized
      Message 2 of 6 , Jan 12, 2010
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        I have a Big Dummy with a Rolhoff and love it.
         
         
         

        The bicycle is the most civilized conveyance known to man.  Other forms of transport grow daily more nightmarish.  Only the bicycle remains pure in heart.  ~Iris Murdoch, The Red and the Green
      • palatine_ej
        I d love to own a Rolhoff, if I did I d put it on my mountain bike! I wouldn t worry about using an Alfine on a cargo bike. IMHO, it has more than enough
        Message 3 of 6 , Jan 12, 2010
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          I'd love to own a Rolhoff, if I did I'd put it on my mountain bike!

          I wouldn't worry about using an Alfine on a cargo bike. IMHO, it has more than enough range and steps. WRT durablity, I've cranked 300lbs of bike/rider/gear on my Alfines, up steep trails that turn into hikes, in a 22" gear. Just imagine how much torque the Alfine is converting right before I give up, it's never flinched yet. My results aren't rare:
          http://forums.mtbr.com/forumdisplay.php?f=154

          I don't have an issue with 300% range on an IGH. My Alfine mountain bike has 22"~68" range, I'd like a little lower but not much, at some point I just hike up the hill. I don't need much higher, I can spin it to ~20mph, only time I do that is downhill on the road.

          On the street, a 300% range IGH gives 27" to 90", I can climb a 25% grade and spin to ~50mph down a hill, that's enough for me, esp since now I'm approaching my dotage!

          Eric
        • Mark Stonich
          ... Several years ago I built a longtail for cargo. But before I built the deck I ended up temporarily turning it into a kid back tandem. I was finally
          Message 4 of 6 , Jan 12, 2010
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            At  1/11/2010 06:41 PM +0000, Rich wrote:
            Have any members bought or assembled a long tail cargo bike such as the Xtracycle, Surly Big Dummy, Kona Ute or Yuba Mundo? How are they to use and ride with the extended wheelbase?

            Several years ago I built a longtail for cargo.  But before I built the deck I ended up "temporarily" turning it into a kid back tandem.   I was finally going to finish it as a cargo bike this year.  But now my younger son is dating a woman with a 4 y/o.
            http://www.bikesmithdesign.com/MyBikes/kt/allie.jpg

            Handling;
            Just like riding a tandem with no stoker.  Because of the forward center of gravity, these things react quickly in the roll axis.  This is great for low speed balance but might feel a little squirrely at high speed.  This is more noticeable unladen of course.  In tight turns you have to swing the front wide because the rear wheel's path will be well inside the front's.  Once you get used to it, they handle just fine.  (Easy for me to say; I own 5 tandems, including a recumbent with an 86" WB.  Your learning curve may be a little longer.)

            I am considering one of the above. I note that the Surly literature states that the frame was designed to work with the OEM2 version of the Rokloff hub, in combination with a chain tensioner, though initially I would probably go with a non IGH drivetrain.

            My concern would be that any IGH other than the Rohloff might not handle the potential weight as none are rated for the service and the SRAM hubs specificallly state that they are not suitable for cargo bike service. Per some reports the NuVinci might stand up to such use.

            Are you worried about bending axles or overloading the hub?  I wouldn't worry about either unless you are a big guy with steep hills and very heavy loads.  Over the years there've been plenty of tandems with Sturmey 3 and 4 speeds.

            A small rear wheel will be stronger and give lower gearing for a given input ratio.

            My current "cargo bike" is an old Raleigh 3 speed with a Sturmey S5 geared 26-46.   With Wald's biggest Newsboy baskets and "Grocery Getter" panniers on low rider fork mounts.  I can carry quite a bit of weight and it seems to be even more stable with a load of canned goods on the low riders.

            Mark Stonich;
              BikeSmith Design & Fabrication
                5349 Elliot Ave S. Minneapolis, Minnesota 55417 USA
                     Ph. (612) 824-2372  http://bikesmithdesign.com
                                 http://mnhpva.org

          • Rich
            If choosing an IGH for a longtail cargo bike, other than the Rohloff, I would probably go with the NuVinci. Slightly wider range than the Alfine and per the
            Message 5 of 6 , Jan 12, 2010
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              If choosing an IGH for a longtail cargo bike, other than the Rohloff, I would probably go with the NuVinci. Slightly wider range than the Alfine and per the manufacturer's specs it has the highest torque input limit of any IGH made. 130NM for the NuVinci versus 100NM for the Rohloff and 85NM for the SRAM P5 Cargo. No other hubs list torque limits that I have been able to find unfortunately.

              One BF member has reported successful use of the NuVinci on a cargo longtail with electric assist motor without problems so far. IIRC he also reported destroying a SA 8 speed and SRAM 7 speed hubs on the bike as well as short term use of a Rohloff w/o any problems.

              As the Big Dummy frame has vertical dropouts a chain tensioner is needed for an IGH anyway so also possible to use a dual chainring setup in front for extending the gear range even further.

              Reading the specs on the complete Big Dummy the gear range is about 570% with a 20.4" low and about an 118" high. The high seems ridiculously high but that is what comes from using an 11-34 rear casette. From what I have read about both wear and efficiency it seems to me that 11 tooth casette sprockets make little sense.

              Rich Wood


              --- In Geared_hub_bikes@yahoogroups.com, "palatine_ej" <danstrom@...> wrote:
              >
              > I'd love to own a Rolhoff, if I did I'd put it on my mountain bike!
              >
              > I wouldn't worry about using an Alfine on a cargo bike. IMHO, it has more than enough range and steps. WRT durablity, I've cranked 300lbs of bike/rider/gear on my Alfines, up steep trails that turn into hikes, in a 22" gear. Just imagine how much torque the Alfine is converting right before I give up, it's never flinched yet. My results aren't rare:
              > http://forums.mtbr.com/forumdisplay.php?f=154
              >
              > I don't have an issue with 300% range on an IGH. My Alfine mountain bike has 22"~68" range, I'd like a little lower but not much, at some point I just hike up the hill. I don't need much higher, I can spin it to ~20mph, only time I do that is downhill on the road.
              >
              > On the street, a 300% range IGH gives 27" to 90", I can climb a 25% grade and spin to ~50mph down a hill, that's enough for me, esp since now I'm approaching my dotage!
              >
              > Eric
              >
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