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Re:Hub motor or stokemonkey?

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  • Bruce Alan Wilson
    While the Stokemonkey mounts won t fit anything but an Xtracycle or Big Dummy, it MIGHT be possible to adapt it to something else; it has been done. Todd
    Message 1 of 25 , Dec 30, 2009
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      While the Stokemonkey mounts won't fit anything but an Xtracycle or Big Dummy, it MIGHT be possible to adapt it to something else; it has been done.  Todd doesn't encourage it, but it has been done.  Does your local university have a School of Engineering?  If so, you might be able to find a bright Mechanical Engineering student who'd be willing to take up the challenge of adapting a Stokemonkey to a Madsen.  I talked to a ME I know about it, and he says that he thinks he could do it, but would have to study it a little more.
       
      Before you go to a hub gear, I'd look at Ecospeed: http://www.ecospeed.com/ or Cyclone http://www.cyclone-usa.com/; they are based on similar engineering principles to a Stokemonkey, but are adaptable to more types of bike.
       
       
       

      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
    • jj
      ... Don t believe it: He still comes out and pokes at our Stoked X s whenever we swing by the shop :-D Seriously, Todd has created an amazingly user friendly
      Message 2 of 25 , Jan 1, 2010
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        Todd from Clever wrote:
        >
        >
        > I also removed the foot retention "requirement" from the product's
        > warnings some months ago. I admit that my motivation in putting that
        > in in the first place was partly to filter out potential customers who
        > I feared might not be experienced enough bikers to use SM safely.
        > Heck, maybe that warning was a secret appeal to hard-riding
        > early-adopter types whose feedback I sought. After many years of
        > riders of many skill levels and no injuries reported, well, I've relaxed.
        >

        Don't believe it: He still comes out and pokes at our Stoked X's
        whenever we swing by the shop :-D

        Seriously, Todd has created an amazingly user friendly tool.

        My wife had 3 heart attacks in 2002, dropped dead (and was revived in
        2006) and clocked hundreds of miles on her stoked X in 2009. It
        alleviates the fear of being "stuck", unable to get home when she is at
        the bottom of the hill near our house. Even if she is using the max
        power from the stoke, and is barely able to pedal, she can get home. Oh,
        and she lost 20+ lbs this year, to boot (we think she lost more, but
        that is the stated amount by her cardiologist.)

        I bought a Stoke to keep up with HER, but I found it to be very very
        useful for almost everything, from giving strangers rides at Farmers
        Market, to hauling home xmas shopping, to riding in the WNBR and helping
        folks on bike-moves.

        When our kids are old enough for a car, they get a Stoked BigDummy
        instead. Much more useful.

        JJ

        >
      • todd
        ... Hub motors will beat SM in cost-effectiveness for cruising along at 15-20mph in flat or gently rolling terrain. For what you describe, it s different. For
        Message 3 of 25 , Jan 1, 2010
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          --- In rootsradicals@yahoogroups.com, "Morgan Scherer" <morganes@...> wrote:

          > Any more thoughts on the relative merits of the stokemonkey versus a good cycle9 hub motor?

          Hub motors will beat SM in cost-effectiveness for cruising along at 15-20mph in flat or gently rolling terrain. For what you describe, it's different. For extended loaded climbing, the cost difference versus hub motors may well be recovered or reversed by the efficiency differences and the lower cost of batteries this implies.

          I'm going to get a little technical here, and i'll try to be terse because I don't want to go on too long about a product I sell in this forum. Apologies in advance if I succeed only in confusing things.

          You wrote previously:

          "Including myself, I'm wanting to haul
          about 360 lbs for at least 15 miles though hilly terrain on one charge. I want
          to the motor to be able to help on the flats for those times I want to hurry
          (maybe going 15mph, when I would normally go 12), though in reality I've tended
          to mostly use electric assists in the past to increase my speed on hills (maybe
          12 mph instead of 3)"

          Have a look at http://www.mne.psu.edu/lamancusa/ProdDiss/Bicycle/BIKEcalc1.HTM . Ignore most fields; concentrate on total weight, desired speed, and steepness of grade. Using your numbers I come up with about 500W being the power requirement for going 5mph up a 10% grade. San Francisco's steepest grades are 31%, and I know Seattle is almost as hilly, so 10% is pretty modest by local standards.

          Now click on over to http://www.ebikes.ca/simulator/ , which models the power/speed/efficiency/torque of several hub motors, including the one Stokemonkey is based upon. Assuming a 36V battery and 20A controller (as a starting point -- more later) you'll see that pretty much all of the motors can produce around 500W at their optimum -- the kind of power you need to move up that hill with your kids. But there's a catch.

          The thing with hub motors is that their power and other characteristics are tied directly to road speed. 500W is what you need to take that hill at 5mph. But look: the large majority of hub motors produce their ~500W max at a speed between 15-20mph. At 5mph, most of these motors can put out closer to 300W. If you want to maintain your 5mph to keep from slipping to an even weaker part of the motor's curve, you must contribute 200W. You may be fine with that, but the motor efficiency at this part of the curve is seldom better than 50%. The other 50% is turning into heat, which, even if your motor can dissipate that without becoming an even more resistive heating element, isn't something you can afford if you want to go 15 miles loaded in hills on a single charge: not unless you want to carry an absurd weight and expense of batteries.

          How much battery do you need to go 15mi with your load? Let's say half of it is 10% uphill, and the rest is "free" downhill. 7.5 miles at 5mph will take 1.5 hours. At 500W, that's 750 watt hours. At 36V, that's about 21Ah of battery. Now, if you're running at 50% efficiency, you'll actually need 42Ah. I admit that this is a somewhat contrived worst case; plug in your own numbers. But remember to go back and add the weight of the extra batteries to the power requirements...

          Stokemonkey can apply its full ~500W at any speed you have a gear for, and at ~70% efficiency. Pedal faster -- say, adding that 200W -- and the efficiency can go up to around 80%.
        • Jeff Snavely
          A car may drive the wheels as long as your foot is on the gas pedal, but you know not to keep your foot on the gas if you want to slow down. Everyone tries to
          Message 4 of 25 , Jan 1, 2010
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            A car may drive the wheels as long as your foot is on the gas pedal, but you know not to keep your foot on the gas if you want to slow down.

            Everyone tries to coast a fixie at least once, and most people will try to coast a stokemonkey without lifting the throttle at least once (I have, but my wife hasn't). The stokemonkey is a much less traumatic experience though. Lift the throttle, put your foot back on and keep riding.

            Other than that one incident, I have never felt that my feet were being driven.



            On Wed, Dec 30, 2009 at 4:46 PM, Andrew Kreps <andrew.kreps@...> wrote:
             

            On Wed, Dec 30, 2009 at 1:35 PM, Jeff Snavely <jsnavely@...> wrote:


            I fail to see the correlation between a stokemonkey and a fixed gear bike. And I own both.



            A fixed-gear bike, while moving, drives the pedals regardless of the pressure you exert on them.

            A Stokemonkey, while engaged, drives the pedals regardless of the pressure you exert on them.  

             

          • David Dannenberg
            Ya know Papa, I think you are right. A motorcycle is a motorcycle and a bike is a bike, even an electric one. (and there are now electric scooters available
            Message 5 of 25 , Jan 2, 2010
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              Ya' know Papa, I think you are right. A motorcycle is a motorcycle and a bike is a bike, even an electric one. (and there are now electric scooters available to complicate this simple formula). It might be amusing to make a gas powered bike, but not likely to be cost efficient or as well engineered as a purpose built gas powered motorcycle or scooter.

              I have a 1964 Honda Trail 90 hanging in the garage being very slowly restored (well, made functional). Planned use is as a grocery getter in the neighborhood--too small for anything much more than city streets. Your 125 sounds like a beaut!

              Dave
            • Miguel Barroso
              Hi there, I ve just joind this group. I m 36, Portuguese, and live in Lisbon. I currently have a 97 GT Tequesta, that I plan to convert. I considered buying a
              Message 6 of 25 , Jan 2, 2010
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                Hi there,
                 
                I've just joind this group.
                 
                I'm 36, Portuguese, and live in Lisbon.
                 
                I currently have a 97 GT Tequesta, that I plan to convert. I considered buying a Surly Big Dummy frame, but the price, and the fact that they are not sold here in Portugal, made me forget this idea.
                So, this month there will be another rootsradical here in Lisbon!
                 
                Cheers,
                 
                Miguel Barroso
              • Bruno
                Welcome Miguel, On Sat, Jan 2, 2010 at 10:33 PM, Miguel Barroso ... The price may be a deterrent indeed, but if you d want to get one they are available
                Message 7 of 25 , Jan 2, 2010
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                  Welcome Miguel,

                  On Sat, Jan 2, 2010 at 10:33 PM, Miguel Barroso <miguelbarroso@...> wrote:
                  I currently have a 97 GT Tequesta, that I plan to convert. I considered buying a Surly Big Dummy frame, but the price, and the fact that they are not sold here in Portugal, made me forget this idea.

                  The price may be a deterrent indeed, but if you'd want to get one they are available through you know who. ;-P That wouldn't be a reason for not getting one.

                  Cheers,
                  Bruno
                • Cara Lin Bridgman
                  I ve got one of the tightest fits of stokemonkey to bike frame. I put a stokemonkey on a 16 Surly Instigator frame. There are literally 2-3 mm to spare on
                  Message 8 of 25 , Jan 6, 2010
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                    I've got one of the tightest fits of stokemonkey to bike frame. I put a
                    stokemonkey on a 16" Surly Instigator frame. There are literally 2-3 mm
                    to spare on all three sides and between chain and frame. The only way
                    to make it fit was to put tongue of the free-radical below the chain
                    stays, not above.

                    CL

                    Sean Moore wrote:
                    >
                    > Alas, not to be. I just went and measured my bike. Stokemonkey won't
                    > fit on my ~19in Bianchi Milano. Chain clearance was close, room in the
                    > triangle isn't in the ballpark.
                    > --
                    > Sean Moore
                    > moore.sean@... <mailto:moore.sean@...>
                  • Cara Lin Bridgman
                    That s why I got the stokemonkey--so I could get home, which is near the top of a 280 m hill. CL
                    Message 9 of 25 , Jan 6, 2010
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                      That's why I got the stokemonkey--so I could get home, which is near the
                      top of a 280 m hill.

                      CL

                      jj wrote:
                      > It
                      > alleviates the fear of being "stuck", unable to get home when she is at
                      > the bottom of the hill near our house.
                    • Jeff Snavely
                      Yea, I changed my wife s Big Dummy from an 18 to a 16 at the last minute. That turned out to be a mistake. The stokemonkey fits, but not like it really should.
                      Message 10 of 25 , Jan 7, 2010
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                        Yea, I changed my wife's Big Dummy from an 18 to a 16 at the last minute. That turned out to be a mistake. The stokemonkey fits, but not like it really should. I paid a shop to do it, but had to re-do all of their work when I got it home so I felt the full pain of fitting it in there.

                        I am sure my wife appreciates the slightly lower standover, but I would definitely buy the 18 if I were doing it over.


                        JeffS

                        On Thu, Jan 7, 2010 at 2:33 AM, Cara Lin Bridgman <shokulan@...> wrote:
                         

                        I've got one of the tightest fits of stokemonkey to bike frame. I put a
                        stokemonkey on a 16" Surly Instigator frame. There are literally 2-3 mm
                        to spare on all three sides and between chain and frame. The only way
                        to make it fit was to put tongue of the free-radical below the chain
                        stays, not above.

                        CL



                        Sean Moore wrote:
                        >
                        > Alas, not to be. I just went and measured my bike. Stokemonkey won't
                        > fit on my ~19in Bianchi Milano. Chain clearance was close, room in the
                        > triangle isn't in the ballpark.
                        > --
                        > Sean Moore
                        > moore.sean@... <mailto:moore.sean@...>


                      • todd
                        let me guess: hard to get bracket out of path of right-side chain, especially if a derailleur gearing system? do-able, but tedious, i agree!
                        Message 11 of 25 , Jan 7, 2010
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                          let me guess: hard to get bracket out of path of right-side chain, especially if a derailleur gearing system? do-able, but tedious, i agree!

                          --- In rootsradicals@yahoogroups.com, Jeff Snavely <jsnavely@...> wrote:
                          >
                          > Yea, I changed my wife's Big Dummy from an 18 to a 16 at the last minute.
                          > That turned out to be a mistake. The stokemonkey fits, but not like it
                          > really should. I paid a shop to do it, but had to re-do all of their work
                          > when I got it home so I felt the full pain of fitting it in there.
                          >
                          > I am sure my wife appreciates the slightly lower standover, but I would
                          > definitely buy the 18 if I were doing it over.
                          >
                          >
                          > JeffS
                          >
                          > On Thu, Jan 7, 2010 at 2:33 AM, Cara Lin Bridgman <shokulan@...>wrote:
                          >
                          > >
                          > >
                          > > I've got one of the tightest fits of stokemonkey to bike frame. I put a
                          > > stokemonkey on a 16" Surly Instigator frame. There are literally 2-3 mm
                          > > to spare on all three sides and between chain and frame. The only way
                          > > to make it fit was to put tongue of the free-radical below the chain
                          > > stays, not above.
                          > >
                          > > CL
                          > >
                          > >
                          > > Sean Moore wrote:
                          > > >
                          > > > Alas, not to be. I just went and measured my bike. Stokemonkey won't
                          > > > fit on my ~19in Bianchi Milano. Chain clearance was close, room in the
                          > > > triangle isn't in the ballpark.
                          > > > --
                          > > > Sean Moore
                          > > > moore.sean@... <moore.sean%40gmail.com> <mailto:
                          > > moore.sean@... <moore.sean%40gmail.com>>
                          > >
                          > >
                          > >
                          >
                        • Jeff Snavely
                          My crank arm was hitting the bracket after I aligned things where I wanted them. The bike shop had apparently twisted the bracket (and chainline) to avoid
                          Message 12 of 25 , Jan 7, 2010
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                            My crank arm was hitting the bracket after I aligned things where I wanted them. The bike shop had apparently twisted the bracket (and chainline) to avoid this. I cut the end of the bracket off. On a larger frame, I would have offset the motor slightly for a better chainline. I didn't have that option here though. I had to have it centered for every mm of available clearance. I'm hoping we can keep it running as the chain wears. If not, I will just replace the chain more often.

                            It wouldn't have been such a big deal if I hadn't been so pissed about having to redo it in the first place. What really put me over the top was finding that the shop monkey had clamped the SM mount OVER the top of the water bottle bosses, crushing them into the tube.

                            It's been months and I still haven't calmed down enough to lodge my complaint.






                            On Thu, Jan 7, 2010 at 4:20 PM, todd <todd@...> wrote:
                             

                            let me guess: hard to get bracket out of path of right-side chain, especially if a derailleur gearing system? do-able, but tedious, i agree!



                            --- In rootsradicals@yahoogroups.com, Jeff Snavely <jsnavely@...> wrote:
                            >
                            > Yea, I changed my wife's Big Dummy from an 18 to a 16 at the last minute.
                            > That turned out to be a mistake. The stokemonkey fits, but not like it
                            > really should. I paid a shop to do it, but had to re-do all of their work
                            > when I got it home so I felt the full pain of fitting it in there.
                            >
                            > I am sure my wife appreciates the slightly lower standover, but I would
                            > definitely buy the 18 if I were doing it over.
                            >
                            >
                            > JeffS
                            >
                            > On Thu, Jan 7, 2010 at 2:33 AM, Cara Lin Bridgman <shokulan@...>wrote:

                            >
                            > >
                            > >
                            > > I've got one of the tightest fits of stokemonkey to bike frame. I put a
                            > > stokemonkey on a 16" Surly Instigator frame. There are literally 2-3 mm
                            > > to spare on all three sides and between chain and frame. The only way
                            > > to make it fit was to put tongue of the free-radical below the chain
                            > > stays, not above.
                            > >
                            > > CL
                            > >
                            > >
                            > > Sean Moore wrote:
                            > > >
                            > > > Alas, not to be. I just went and measured my bike. Stokemonkey won't
                            > > > fit on my ~19in Bianchi Milano. Chain clearance was close, room in the
                            > > > triangle isn't in the ballpark.
                            > > > --
                            > > > Sean Moore
                            > > > moore.sean@... <moore.sean%40gmail.com> <mailto:
                            > > moore.sean@... <moore.sean%40gmail.com>>
                            > >
                            > >
                            > >
                            >


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