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Does a mid drive really need a freewheel?

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    Does a mid drive really need a freewheel?

    I have a couple donor bikes with mag wheels, and a Nuvinci 171b CVT hub that use the dreaded threaded on freewheel format. With a Bafang mid drive do I even need a freewheel at all? There is a 1 way clutch in the cranks and another at the motor. Maybe it's time to just weld one of those useless suckers solid?

    One hidden benefit would be downshifts without pedaling. maybe not at a stop, but better otherwise.
    Last edited by Retrorockit; 08-26-2022, 07:37 AM.

    #2
    No reason you need a freewheel at the rear hub, the ring can turn forward freely just as easily as you can pedal without the motor running or the motor turning without pedaling... both BBS clutches will be freewheeling as the ring turns...

    Comment


      #3
      I asked Sunrace about their new freewheels for mid drive Ebikes and got blown off. So now it's time for plan B.

      Comment


        #4
        Shimano had a system like that around 1980 I think called the Positron. Freewheel was on the crank just like a BBS. Last gen of the Schwinn Varsity was one of the models that got it. That system worked OK because all you were trying to spin was the chain ring. In this case I think there may be too much drag and you would end up yanking on the derailleur cage when coasting then it would have to snap back when you went back on it. Having the chain going slack on the top opens up a lot of bad possibilities.

        Comment


        • Retrorockit
          Retrorockit commented
          Editing a comment
          I'm actually having a little of that right now.One bent tooth on one cog plucks the chain when it's on the next gear and then it snaps back.
          I may set up one of the mag wheels and give it a try. The Schwalbe tire fiasco has brought that project to halt for now. I do already have a top roller chain guide in place. Maybe that will save me.

        • AZguy
          AZguy commented
          Editing a comment
          I guess having top chain slack being bad is true but it seems to me that the motor clutches are so low-drag and the rear wheel accelerations also so very low that it's hard for to imagine it being a reality...

          YMMV

        #5
        It should be pretty easy to go out and test. IF you don't have a 'dork disk' you should be able to just run a small zip tie through a slot in the large cog and tie it to a spoke.

        Comment


        • Retrorockit
          Retrorockit commented
          Editing a comment
          Not sure what a "Dork Disc" is, but I think I want one! I have some stainless steel zip ties that are probably up to the task. I'm seeing a big upside to this as far as multigear downshifts when braking goes. If I put the zip ties at a trailing angle from the spokes it should work well.
          My olde XT hubs actually have some cutouts in the spoke flanges I can use. I'm already running Rapid Rise stuff so the difference may not be as obvious to me. So if someone else wants to play along it might be useful.
          Thanks for that tip. I won't have to create a mag wheelset try this idea. I need a new cassette right now anyway so I'll give this a try.
          Last edited by Retrorockit; 08-27-2022, 05:35 AM.

        #6
        Originally posted by 73Eldo View Post
        Not sure what a "Dork Disc" is, but I think I want one!
        You remember from the old days / ways the metal or plastic discs behind the freewheel, used to keep the derailleur or chain from taking a ride in the rear wheel spokes.

        Or maybe worn with pride during your next "intimate interaction".
        Last edited by ncmired; 08-30-2022, 02:42 AM.
        BBSHD / BBS02 IGH Builds: Nexus / Alfine 8: 1 2 3 4 5 6, Rohloff: 1

        Comment


        • Retrorockit
          Retrorockit commented
          Editing a comment
          Is there a spinner version?

        • ncmired
          ncmired commented
          Editing a comment
          Yes, the soon to be announced E-protector - spins and lights up with programmable disco ball effects, lighting also aids during critical navigation.

        • Retrorockit
          Retrorockit commented
          Editing a comment
          Don't forget an ultrsonic whisle so dogs and bats will chase you down the street.

        #7
        There might be another hidden benefit to this. I tried the shift sensor, but got rid of it because acceleration sufffered. But now w ith the 24Ah battery, and Tannus liner in the rear I'm riding faster and at higher power settings than before. I tried the stop pedaling power cut method, but this also delayed the shift until power came back on because the cassette stopped too. This may allow me to cut power but have the shift completed at the same time.

        Comment


          #8
          I did the mod. First try with the stainless steel zip ties didn't work. They won't twist enough, and won't pull through if they aren't straight. So after cutting a 1/2 dozen of them out of the hub with a cable housing tool, I went with 3 plastic zip ties. They have to go in near the hub so they don't bump the chain on the smaller cogs. But they went through 3x holes in the XT flange, through 3 inner cog holes, and over the flange. I can get 3 more in there if needed. But they aren't just tied to the spokes. I can report that the front freewheel is almost as loose as the rear. Spin the rear wheel with the bike upside down and it keeps turning with the pedals stopped, and the chainring still going. I'll report back after a test ride.

          Comment


            #9
            I did the test ride, about 30 miles. This is a very nice mod. Absolutely no problems found and I can make a smooth silent shift up or down any time the bike is moving. Real time smooth shifts. Stopping the pedals with the driveline still moving works great. It can be a little hard to know if you actually stopped, but the old Bendix 2 speed kick back works great (really showing my age here).
            Thanx 73 Eldo for the zip tie idea. Looping it though the hub instead of just the spokes means it won't migrate into the chain area. Rapid Rise still lets me shift when stopped, but that won't be needed very often with this setup. RR pulling cable for upshifts is still real solid under power. I'm going to calls this the "BBSHD Fixie Mod". I didn't think there was anything else I could do to this bike......

            Comment


            • 73Eldo
              73Eldo commented
              Editing a comment
              Ahhh the Bendix 2 speeds. When I worked in a shop in the 80's they would still come in for repair from time to time so I got to work on and test ride them occasionally. I don't remember if we could still order the parts at that time or if we just had em as NOS since our shop had been around a long time.

              I remember one that the customer would bring in every year for service because the guy would ride like 1000 miles per season. It was a unique bike, it was one of the hand built Paramount frames that I'm sure would have originally came with Campy stuff on it but he had turned it into a custom touring bike sort of thing, It did ride really nice, for the era was a very lightweight and streamline bike with no cables since it had the coaster brake and no shifting. Guy was ahead of his time, if he was around now days he may be a single or fixie guy. I think he was in his 70's when I knew him.

              I thought they were really cool and were a major improvement over a single speed but not as 'complex' to operate as a 3 speed. There were different gearing from what I remember you could identify by the color bands on the hub. I think you could get overdrive or under drive. I tried to put one on a commuter bike but it wasn't the right one so it made for a pretty crappy ride. There is a slight chance its still in a box somewhere, I remember pulling it out and reusing the rim it was on.

            #10
            Interesting to hear your results. I may give it a try just to see if it works for me too and if I have any impression of things being different for better or worse. If nothing else it should remind me of riding my Varsity 40 years ago. I'm pretty sure those still had a freewheel of sorts in the back because I remember using my foot to jam up the chain ring to make the chain go slack. I wonder how many nylon ties you would need to make it reliable but still break loose if needed? Just thinking of the time I got my pants leg stuck in the chain ring... Now that I think about it that may also be how I discovered that my Varsity had a rear freewheel too.

            Comment


              #11
              The derailer cage is still there as a relief for too much tension. Since I'm running a Gripshift/ Rapid Rise I can say that this might be better than Rapid Rise. I can drop a bunch of gears w/o pedaling and the shift is done already. No need to pedal it into gear. With a Gripshift it's pretty much dialomatic shifting. There were 6 holes in the XT hub, and 6 holes in the spokes of the inner cog. But after the battle with the stainless zip ties I just used 3 regular ones. You really need to keep up with bicycle fashion. A pair of pant with one long and one short leg is the way to go now. Shows off the grease stain on your right calf to prove you're the real deal.

              Comment


                #12
                Here's the Shimano version.

                Years ago Shimano created a drivetrain called Front Freeweel System, or FFS for short. You don't have to be pedalling to shift. You can shift while coasting....

                Comment


                  #13
                  Mine was Positron II. Index shifting from 1976.

                  Let’s look back on Shimano’s 100 years from “Products and technologies” This page covers information on POSITRON.



                  I think mine was an 82 Deluxe Varsity, sky blue. I could be wrong about the year but it was around there. I had forgotten about the Deluxe part till just now but I remember making a point bragging that mine was Deluxe.

                  Vintage Schwinn Varsity was made from 1951 to 1986. This page shows images and text from old catalogs of this classic bicycle.



                  I think it may have been some sort of law that if you were between 10 and 18 years old between 1951 and 1986 that your first non 20" wheel bike had to be a Schwinn Varsity. Or was that just in my area? The blue Huffy Omni 10 speed was was also popular if you didn't have the big bucks to buy a low end Schwinn.

                  Comment


                  • Retrorockit
                    Retrorockit commented
                    Editing a comment
                    I had a metallic green Scwhinn Collegiate 1x5 bike that was absolutely beautifu with stainless fendersl, and a silver 2x5 Scwinn Letour (not hardly LOL) that had steel rims because I didn't like the gold color of the alloy rim version. Both got stolen her in South FL. But good reliable bikes at a good price.

                  • 73Eldo
                    73Eldo commented
                    Editing a comment
                    They did a special remake of the Collegiate for only $1000. They did OK on capturing a lot of the look of the original but the chain ring / chain guard is the first thing that doesn't look right to my eye then the black derailleur, you would think someone makes a polished aluminum one. I just flipped through some online photos and it looks like it always had a full chain guard. I wonder why they didn't bother? You see them on plenty of cruiser types of bikes so someone clearly makes them still.


                  #14
                  There sure were were a lot of 'em around. Sheldon Brown wrote:
                  Remembering the bike today, it's easy to forget that for the first years of its production, its sales (combined with its slightly upscale brother, the Continental) were greater than those of all other U.S. derailleur bikes combined. When the production run was finally over, the Schwinn Varsity had been manufactured in greater numbers than any other single model of derailleur-geared bike in the world ever.

                  ...

                  The Varsity is the single most significant American bicycle.


                  My first multi-speed bike was a '68 or so Raleigh Robin Hood 10-speed. Why Raleigh and not Schwinn? Because the nearest bike shop sold the Raleigh line (IIRC the shop owner was English). I'm pretty sure the Varsity would have held up better. But not soon after I scarfed up a well-beat Schwinn Sting Ray - now we're styling.

                  Nearest shop brand loyalty was pretty common. On the local harbor, almost everybody had Evinrude / Johnson brand outboard motors. Meanwhile, the next major harbor over mostly had Mercury outboards. Yup, what brand is the shop ...
                  Last edited by ncmired; 08-28-2022, 02:05 PM.
                  BBSHD / BBS02 IGH Builds: Nexus / Alfine 8: 1 2 3 4 5 6, Rohloff: 1

                  Comment


                  • 73Eldo
                    73Eldo commented
                    Editing a comment
                    I think we had 5 bike shops within about 10 miles and 3 for sure were Schwinn. I don't remember what the other ones had since we never went to them. By the time I was working in a shop the 5th shop was gone and the other non Schwinn sold a little bit of everything. They were the only Cannondale dealer in the early aluminum days. Oddly of the 5 that is the only one that is left 30 some years later, not being tied to one primary brand really seemed to work out for them. Now that I think about it I think they were the Raleigh dealer as well as Bianchi and Peugeot.

                    My bikes before the Varsity came from Sears, Montgomery Wards, or Target. I have clear memories of my brother getting a bike from Target, I remember him wheeling it up to the checkout along those red stripped aisles. I don't remember being in the store with any of my bikes. I know I was there for the Varsity but the others may have been gifts so I didn't actually go to the store.

                  #15
                  Nobody really knew much about bicycles back then. Schwinn was respected. But if you wanted your "English racer" to actually be English then you went with Raleigh. I thought Raleighs looked boring. Schwinn made some flashy looking bikes the worked well.

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