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Mid drive cassettte zip tie mod.

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  • AZguy
    commented on 's reply
    Haha, if that were the case a grip shift would be better since they can be mounted on either side more readily than trigger!! ;-}

    And a right side trigger is fully compatibility with twist throttle


    I just prefer triggers - had one bike with grip shift (early 90's) and even after a few years of riding it they just didn't gel with me...

  • Retrorockit
    commented on 's reply
    But I run Rapid Rise low normal deralleurs. they would all be upshifts for me.
    Tell the truth now. You actually run trigger shifters because you have a RH twist throttle so you can play make believe motorcycle.

  • AZguy
    commented on 's reply
    FWIW there are plenty of indexed trigger shifters that do multiple gears in one push (mine does four) and not a big deal to push twice (for eight)

  • Retrorockit
    replied
    Here are my recommendations if you want to try this mod.
    1- Have a well lubed front freewheel in your Mid drive. This usually means very light grease or oil on the pawls, not heavy grease.
    2- A gripshift installed. The whole point of this is to be able to shift to any gear any time. The myth that Ebikes can only shift one gear at a time is nonsense. SRAM made gripshifts for both their own "1:1" system, and Shimano's "2:1" Rumor has it that SRAM 11 speed NX (1:1.2) works with Shimano XT (1:1.1) 11 speed stuff.
    3- Good chain management with no friction added to the system. Good chainline with Wide/Narrow chain ring and a modern clutch derailer will probably work. Bit I don't have any of those things and I made it work anyway.
    4- A 2 leg center stand is nice to have. You can spin up the rear wheel with the motor and test shift up and down. This allows you to see how your chain management is working (or not). It also allows you to show off how the bikes shifts. Just be sure the back wheel doesn't touch the ground while twisting the gripshift backwards.
    5- Start with a single small zip tie. It's all that's needed for this to work, and if you get to the point where it no longer breaks then go to the friction drive setup.
    6- An extra link in the chain to allow for some slack to come and go in the top run of chain is helpful, but maybe not needed with the friction drive setup.

    Leave a comment:


  • Retrorockit
    commented on 's reply
    I'm guessing that Shimano did each cog separately because the math said each cog would have different force on the chain. Probably a different resistance for each one.

  • Retrorockit
    commented on 's reply
    With this mod the pedals shouldn't be turning.Just the chainring. I haven't had this with the BBSHD. Maybe your front freewheel is sticking.

  • Retrorockit
    commented on 's reply
    I rode it around under power. The square section rubber ring instead of the the zip tie is working just fine. It's back to shifting like an IGH.
    I had tried putting the motor back together before and coulbn't get it to go in, left and did some other things for awhile. I tried putting the rotor in by itself, and that was the problem. It seems the first try I had knocked some grease down into the blind hole the small end of the shaft goes into. It was hydraulic locked and couldn't go in. Once I Q tipped the grease out it went in OK. I put some thermal paste between the stator and housing while it was apart. The new rotor, and old motor with the California Ebike conversion bearing(and shim) seems to be working.
    Last edited by Retrorockit; 07-02-2023, 05:08 AM.

  • Retrorockit
    commented on 's reply
    I haven't ridden it under power yet. I'm finishing up a lot of small changes I made while the motor was broken.

  • Retrorockit
    replied
    I got my assorted O-rings to try. Played around with a few setups, and settled on a 3/16" square profile ring behind the cassette. I felt that it wouldn't take a set and lose tension like a round one might. I greased it with some thick silicone Teflon grease that's used for urethane suspension bushings, it won't wash out, but it's designed to prevent sticking between rubber and metal.. Checked the cassette with a torque wrench. About 1 ft/lb to break loose and peak load when spinning it about 3 ft#. The reason to do testing with the zip ties is the bike returns to normal when they break. But once you have a setup that's working this will avoid the hassle of changing a zip tie every now and then. IDK why Shimano went to all that drama and expense making those complicated freewheel sets.

    Leave a comment:


  • Retrorockit
    commented on 's reply
    I've ordered a pile of parts. I'm probably overthinking this, But I've ordered some 3/16"x 1 3/8 ID rings, and some Square section 3/16x1 1/2 ", and I have some 1 3/4" ID rings to go around the smaller ones. I suspect any of them will probably work just fine. The small ring should sit inside the holes in the back of the cassette and the hub flange and give a smooth surface. The square ring will bridge the holes better if I need more grip.I couldn't really find what I needed locally.
    Be aware that a lot of bikes have a spacer of some kind behind the cassette, so the 3/16" dimension may not always apply.
    Last edited by Retrorockit; 06-20-2023, 05:20 AM.

  • Retrorockit
    commented on 's reply
    "The system had many detractors including Sheldon Brown. Most thought it was unnecessarily complex and heavy. I do think it is heavier than a standard freewheel however, it is also quite handy especially if you are an urban commuter who has to do a lot of start and stop biking. By not having to pedal in order to shift, you can shift into and easier gear while you are coasting to a stop so that you’ll be in the appropriate gear when you’re starting off again. You can also shift into a gear while you’re at a stop and as soon as the rear wheel starts moving the chain will fall into the gear that you’ve preselected."
    IDK how to respond to this. Do I have to weigh my zip ties and O rings?
    Last edited by Retrorockit; 06-19-2023, 05:40 AM.

  • Retrorockit
    commented on 's reply
    All you need is zip ties, or thick rubber bands to do the same thing. LOL

  • ncmired
    commented on 's reply
    I found this quote, "each ring has its own set of pawls, so take my advice and don’t open one of these".


  • Retrorockit
    commented on 's reply
    I've only seen the video. But Shimano dragged each cog separately. It was freewheel tech. But the whole cassette approach works just as well.
    Someone with a dork ring suggested the friction method. My XT hubs have a high flange so I can run 1 or 2 O rings to try it.
    Since it basically only moves if the chain gets jammed up somehow it doesn't have to be high tech. It's just to make the chain move around the chainring when coasting. Under power it does absolutely nothing.
    Last edited by Retrorockit; 06-17-2023, 05:30 AM.

  • ncmired
    replied
    On the Shimano FFS freewheel, is that what they did? Ever taken one apart?

    I've never seen one.
    Last edited by ncmired; 06-17-2023, 05:22 AM.

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