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Mid drive cassettte zip tie mod.

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  • 73Eldo
    commented on 's reply
    I just suggest zip tie for every problem. Eventually its got to work on something.

  • Retrorockit
    I must put in here that 73Eldo suggested the zip tie mod. to try this out. I was just the only guy who actually did it. So I did not create the zip tie mod.

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  • Retrorockit
    started a topic Mid drive cassettte zip tie mod.

    Mid drive cassettte zip tie mod.

    I've got enough seat time on this mod. I think I can bring it forward on it's own. It came out of another discussion here which rambled around some.

    The mod consists of putting a single very small 14# rated zip tie around the casstte inner cog and either the hub flange or inner end of the spokes to lock the wheel together with the cassette, but in a breakaway configuration. This is only for mid drives that have a freewheel in the front.

    I've been riding this regularly for about a month now. Fast urban street riding. My bike already had a front chain guide, and from feedback I think it should be part of the mod.


    Shimano offered a system like this in the 1970s. Front Freewheel Ssytem. So it isn't something new.
    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....

    This is why the breakaway feature is needed.
    I had a bunch of viewers ask what happens with a chain jam on a Shimano Front Freewheel System bike. Like if you are riding and you get a pant leg gets caugh...

    1 small 14# load zip tie.

    Here are a couple seat post mounted chain guides. Universal Cycles usually has these.

    I had a very wide chainline and had to convert mine to a roller guide so I could use a longer 8mm Allen bolt as a shaft.

    What it fixes..

    1-On a BBSHD if you are pedaling you are sending power down the chain. With a rear freewheel you must pedal to shift. All shifts are power shifts. In the higher settings this can be a problem.
    2- You must pedal to downshift while braking. The brake switches may cut the power, but why pedal when stopping?
    3- When leaned over in turns you can't shift due to pedal strikes if you pedal. Think traffic circles.
    4- If you're cruising around standing on level cranks you can't pedal, so you can't shift.

    What about this?

    1-Shift sensor switch.
    a- It has a fixed delay. It can rob performance when accelerating and sends mixed messages to following traffic with it's on again off again performance.
    b- When downshifting multiple gears when the delay runs out the power can kick back in while braking.

    2- You still can't shift when stopped.
    a- Since you can shift easily when braking or cornering,or standing, you're more likely to be in the right gear already when you do stop.
    b- A Rapid Rise derailer can do that. But proper RR Gripshifts are very rare parts. I have both, so yes I can actually. Like the chain guide, I already had it.

    What does it do?

    1- Converts your bike to a conventional Motor/Clutch/Transmission layout. If you stop pedaling, it cuts the throttle and releases the front clutch so you can shift. Smooth quiet, consistent shifting.
    Up or down as many gears as you like as long as the bike is moving. I prefer Grip shifters, But I always have.
    2- In a chain suck event the zip tie will break and the bike returns to normal. This has been confirmed to work by a user without a chain guide who rode his bike off of a curb. That's why the chain guide is recommended. But you can try the mod without one if you ride gently to see how you like it.
    3- You control the shift delay with your pedals. Short for rapid acceleration, long for multiple gear downshifts or braking. A quick back pedal eliminated any decay setting going on.

    I haven't broken my zip tie yet, but I carry a few and a pair of tweezers in my flat tire kit just in case. But the bike just goes back to the way it was before if it does break.

    The zip tie should be installed as close to the hub as possible. If it moves up it can touch the chain on the back of the next smaller cog. Also the wheel has more leverage for the breakaway feature to work.

    If you do this with the wheel off the bike you can easily test the breakaway load by grabbing the cassette with rag and turning it backwards until the zip tie breaks.

    Last edited by Retrorockit; 10-11-2022, 08:31 AM.