Mid drive cassettte zip tie mod.

[Retrorockit]

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.
https://electricbike.com/forum/forum...ed-a-freewheel

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.

History.

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

https://www.youtube.com/watch?v=Dwpnxh_Vxpk

This is why the breakaway feature is needed.

https://www.youtube.com/watch?v=J39t1IxAPcg

Parts.
1 small 14# load zip tie.

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

https://problemsolversbike.com/produ...ainspy_-_30979

https://www.gussetcomponents.com/sho...-chain-device/

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.

[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.

[73Eldo]

I just suggest zip tie for every problem. Eventually its got to work on something.

[Retrorockit]

40 mile ride today. 30 yesterday. Bike rides great, no issues with this mod.

[73Eldo]

I tried it today. Fairly short ride, about 12 miles. Got some new sounds. First sound is a clicking when coasting. Its worst in the lower gears so it must have to do with the wonky chain line. In higher gears I probably would not have noticed it. Once I heard it I can even hear it in the higher gears. Any driving force the noise goes away so it must have to do with the chain being pulled over the chain ring rather than the ring pulling the chain. I'm kinda curious to see if the noise changes as I get more miles on it in this configuration. For those that are curious its a Luna Eclipse narrow wide ring with about 2k miles on it and on its 2nd chain that so far isn't showing any signs of wear. Its a 10 speed middle of the range Shimano HG.

Other noise I notice is what I assume is maybe the motor spinning down? Normally the ring is still driving and perhaps making some noise so you don't hear the motor itself still spinning? Its not bad just a different noise than I was used to. So far not really seeing a down side. Once I get used to it it will probably be handy not having to pedal to shift. Little hard to break that habit, have to remember what it was like to ride my Schwinn Varsity that was like that 40 years ago. Pretty sure that would have been the first derailleur bike I would have really ridden so maybe it won't take me long to remember that.

[Retrorockit]

Do you have the zip tie down near the hub? My XT hub had windows in the flange so I used one of those. If it's further out it can bump the chain on the next cog as it goes by. The other possibility I can think of is it may be holding the rear freewheel in a position where the pawl isn't engaged. It should be engaged all the time and driving the bike normally. I've had no sound from mine at all. Maybe zip it so it's holding the rear pawl already engaged.I have my own habit from running low normal derailers for 18 years. I down shift w/o pedaling but give a turn just before I stop to engage the preselected cog. Totally unnecessary now, it's already in gear. This is also where the motor would give a kick because the shift delay was used up when I had a sensor installed. Drive it like a stick shift car. A quick stop or tiny back stroke cuts the power, and releases the clutch. Make whatever shift you want, and pedal again. if you do this with the right foot forward it's actually the same one foot up, one down movement. if you have a shift sensor you might unplug it to see how the mod works alone.
Maybe your front freewheel needs some grease?

[Retrorockit]

I had just lubed mine before I did this mod. But everything in the front is moving now when coasting. I would look there too.

[Retrorockit]

My bike is actuallly quieter after this mod. No rear freewheel clicking when coasting. Just a whir from the chain if I go to a low gear while riding fast. My bike was already pretty quiet for an HT after the Tannus Armour upgrade. So I don't think there is a sound associated with this that wasn't already there for some other reason.

[Retrorockit]

I see a post from Cyclops listed but can't find it in the thread. Maybe a repost?
I should add that this mod doesn't FORCE you to stop pedaling when shifting. You can still shift when pedaling if you prefer that. It gives you the added OPTION of shifting when not pedaling. If you shift when pedaling you will get the same crisp/crunchy shifts you had before. If you have a shift sensor, that should still work . I took mine off before this mod for reasons listed above. So this mod is not an either/or kind of thing. If you do shift when coasting you won't need the shift sensor.
So my comment to backpedal when shifting has more to do with my bike not having a shift sensor, than it does the zip tie mod.

[Cyclops]

Post was "unapproved "???
try again.......did the mod Friday........very cool being able to shift without pedaling. Rode 20km with no issues

[paxtana]

Cool idea!

[Retrorockit]

I've got a couple hundred miles on it now. My bike wasn't typical due to a roller chain guide, and Low Normal derailer setup. But I can shift any time I want to. Even downshift a few gears when stopped (this is not the zip tie, it's the derailer). I have to drag a brake until it's fully in gear then, but it works. Pretty close to an IGH in my case.
So have you tried it?

[Retrorockit]

Here is a very expensive (and noisy) European version of this mod for pedal bikes. Complete with zip tie/ breakaway feature, and top chain guide recommendation.

https://www.pinkbike.com/news/review-intend-rocksteady-magic-cranks-let-you-shift-while-coasting.html

The crank set costs about as much as a BBSHD. So we get it for free.

[Retrorockit]

I might add that the reviewer tested this offroad in Vancouver BC, and liked it. So it does seem to be suited for MTB use.

[Retrorockit]

When I went to lube my chain today I noticed that the zip tie had finally broken off. So that's about 6 weeks I guess. I didn't notice it when riding home. Probably because my Low Normal derailer already allowed downshifts while not pedaling. The bike just went back to normal. Put in a bright yellow one this time. I also didn't pull it very tight. I'll see if that makes any difference. The first one was gray and hard to find on the silver hub and spokes.
i see this thread getting 10-20 views a day, but no comments. is anyone else trying this?

[Retrorockit]

I did get one crunchy launch at the end of a night ride. Probably the zip tie missing. The yellow one lets me glance down every now and then to check on it. The Rapid Rise requires me to pedal it into gear after a non pedaling or downshift. With the zip tie I don't need to do that (only after a stopped shift).

[Bob Anson]

Yes, works GREAT! Now i can downshift several gears to keep the motor in the correct RPM range for the hill, without fumbling with pedaling between single changes. Stopped the gear clanging that was bugging me, 100% easier on the drive train. Only installed 2 of the smallest Ty-wraps @ 180 deg (3/16X4"). Have just Waxed the chain w/PTFE to help the drive chain LAST!! Now it shifts as similar to a motorcycle as i can get it!!

Thanks

[Retrorockit]

Thanks for the feedback.
If you do the zip tie mod with the wheel off, you can easily test the breakaway force by turning the cassette backward with a rag to protect you fingers.One seems to work just fine but add more if you like.

[Retrorockit]

Oh dear I broke another zip tie. It happened at the same place it broke last time. It's my fault for dropping down 5 gears at 30mph. This is an old habit of mine. Before the zip tie i could drop 5 gears and the shift wouldn'y happen until I pedaled it into gear just before I stopped with the brakes still on.. That's the Rapid Rise derailer method. With the zip tie the shift happens at 30mph and pushes the chain forward too fast. It got stuck in the chain guide and the zip tie broke as planned. I just need to do my shifting a little later in the stopping process. I need to match the shifts to the bike speed a little better.
I tend to do this when going from full speed to a dead stop at a crosswalk situation. The bike works just fine with the broken zip tie. Maybe this will solve the broken zip tie mystery.

[Retrorockit]

The single small zip tie broke before the chain got too jammed up. Just had to roll the bike back a couple inches to clear the chain and rode away. Didn't get my hands dirty.

[Mike_V]

Nice reading about the rapid rise low normal setup that you had.

[Retrorockit]

I ordered some 8mm steel rod to use the original chain guide end instead of the roller guide. I think it might work better at keeping the chain down on the chainring. I adjust the roller so it isn't turning all the time. Maybe the other one will be better. The long 8mm bolt through the roller guide was just so easy I went with that setup. Anyway the breakaway feature has been tested and is working, Now I'll see if I can improve on it so that doesn't happen any more..

[73Eldo]

I have got a few rides in on my modded street bike and I'm getting used to the different noises and not having to pedal and shift. Have not yet modded or even ridden my off road bike yet but hopefully that one won't have any issues because having one you can shift and one you can't could cause issues remembering which bike you are on. Only reason it may not work is off road there is a lot more bouncing around so chain drops could be an issue.

[Retrorockit]

I'm looking into upgrading my homemade chain guide. It's so flat here I have no relevant offroad experience.
I did notice the BBSHD has a circle of bolt holes on the back of the gear case. They're small, but plenty of them. I'm surprised no one offers a chain guide kit. Of course no one would plan on my 50T ring so I would be on my own there anyway.
This can drop a chain with no bouncing around. So a bulletproof chain guide would be a big plus. I'm asking at MTBR about this.

https://www.mtbr.com/threads/chain-guide-for-ebike.1211239/

[Retrorockit]

The only noise mine makes is the chain whirring at 30mph when I dump it into lower gears. When that sound stops I know the zip tie broke.
I don't HAVE to dump 5 gears at 30mph w/o pedaling, I can do it later, but I could do it before, so it is an issue for me. When I'm dropping just a gear or 3 for turns this hasn't been an issue. Just top speed to 0 seems to be the situtaion.But that's exactly when I have other things going on.

[Retrorockit]

I broke another zip tie. No idea why. They usually last a month or so, and I knew what happened. So this time I installed 2 of them. My first roadside installation. The tweezers are the right tool for this. It was long ride into strong headwinds, But I don't see what that has to do with the zip tie mod.

[Retrorockit]

I've been riding with 2 zip ties. No problem because of having 2 of them. The breakaway still works. I think my home made chain guide could be better. Instead of a roller that vibrates when it touches the back side of the chain I may do something with a derailer idler or 2 that can hold the chain w/o noise or vibration. But I'll give the more modern derailer a try first.
I did get a Sunrace M9 derailer in. All metal, very heavy spring, and a clutch. Nice large metal sprockets with spokes to lighten them up. I'll give this a try, maybe it has enough tension to pull the slack out all the way around the front freewheel.
I'll have to remove the Rapid Rise XTR setup and go with an SRAM Attack, or Rocket grip shifter But this has native support for 40t cassette cogs. So no hanger extension needed.

https://imgs.search.brave.com/n__cyWfeiYPjXRvqtFuPrlDIbAfSV6r5GSsz6UclRms/rs:fit:720:900:1/g:ce/aHR0cHM6Ly93d3cu/YmlrZXBhcnRzLmNv/bS9pbWFnZXMzL3hs/YXJnZS9SRDAyNDAu/anBn

[Retrorockit]

I made mine with the roller right at he top of the chainring, but I think it needs to happen sooner with this setup. It was OK for side to side from chainline, but the flapping up and down form actual slack seems to need a different solution. I haven't had any chains escaping form the derailer so I think that's the way to go.
Now that I have the shifting control the zip tie offers, I might be able to give up the Rapid Rise and try a more modern derailer.
Now that I'm looking into the toothed chain idler question some more it seems there are lots of choices in the trike community with the 8mm bearing size I'm already using. One source mentioned that toothed idlers were preferred for drive side use. It looks like I can just buy an idler and flip the seatpost calmp to the rear and have something better.

https://hostelshoppe.com/collections/chain-management-idlers

[Retrorockit]

I've done some looking around to improve my (home made) top chain guide issue. The recumbent trike guys do a lot with chain guides and idlers, they use the 8mm Allen bolt for a shaft format.
Terra Cycle seems to have a good selection of parts for this.

https://t-cycle.com/collections/idlers

I edited in a new link here. The T-Cycle idler clamp wasn't strong enough for BBSHD service. Their battery clamp is, but needs an adapter plate made.

https://t-cycle.com/collections/all-battery-mount-parts/products/heavy-duty-frame-clamp

[Retrorockit]

I've also added a Sun Race M9 derailer to my arsenal. The very heavy tension spring will probably pull out the slack all the way around the front chain wheel. But I want to upgrade my guide first, because putting the chain back on with that monster spring might be a chore.This will do away with my vintage Rapid Rise setup. I will need to change shifter, and get rid of the extended derailer hanger, so for me it's a project. For most others just a derailer swap. But I already have my 8 speed gripshifts to take advantage of the better shifting this mod provides.

[Retrorockit]

I got some of the bigger recumbent chain rollers to play with. Unfortunately the new size put the clamp right where the bolt for my motor torque arm is. I also got the nice chain keeper that clamps onto the head of the 8mm Allen bolt they use for shafting. I could get it together ,but it put pressure on the chainring. This turned out to be the wrong thing to do. Adding drag there increases slack in the top run of the chain. Adding the chain keeper pin is even worse. When the chain hits that it put so much slack in from drag that I saw the chain hanging down between the wheel and the chain stay at high speed downshifts. I have a center stand that lets me see what's going on. My home made roller guide is better than I thought it was. I've ordered an offset mounting clamp they offer. I use my old clamp for the first attempt so no waste there. But the non roller guides may not be the solution for this purpose. The M9 derailer is looking like it may be the answer by increasing the tension in the whole system. But I ordered a smaller roller guide also that looks better than the one I have. It has deeper narrower sidewalls, and an O ring to center the chain.
Here's their small affordable idler with 6mm bearing. This might be all it takes. My Blackspire roller with tapered sidewalls does let the chain out every now and then.

https://t-cycle.com/collections/idlers/products/tensioner-mini-idler

Many of Terra Cycle (t-cycle.com) brackets stop at 1.5" clamp size. A couple of them come in 36mm. I suppose this is for 34.9mm seat tube +paint. It should shim down if needed with some aluminum duct tape.
This is the 8mm adjustable offset clamp for the high end 8mm rollers.

https://t-cycle.com/collections/chain-management-accessories/products/5-hole-vertically-adjustable-clamp-on-idler-mount

Anyway this mod is very sensitive to anything that adds drag to the top run of the chain. I already had a roller guide before I tried this mod. It seems to be the way to go.