Mid drive front freewheel mod.

[tomjasz]

Best view.

[nicobie]

Unfortunately, this thread needs to be locked for a while because of too much insulting behaviour.

BTW it's bad forum etiquette to change the wording when quoting somebody, so please don't do it.

thank you,

Nick

[nicobie]

OK, I just spent the last ½ hour deleting and editing posts in this thread for insulting behaviour.

I don't enjoy wasting my time, it makes me unhappy. Next time you two guys go at it I'm just going to delete the whole thing. If that causes good info to disappear, so be it...

[Retrorockit]

For those who are interested in this I've been putting a lot of miles on my bike with this mod. No issues at all. My rides are 30-40 miles long. The shifts are smooth and quiet, and the bike is more versatile. I can shift in more situations, and be in the right gear much easier with this. it makes a big difference on a motor w/o a torque sensor. especially at higher power settings.
As noted above I did already have a front chain guide on my bike. So that may be part of it. I am a believer in twist shifters. I tell my shifter what to do ,not the other way around. Some vendors say an Ebike can only shift one gear at a time. This is total nonsense.

[Retrorockit]

There is a German company that has been offering this for pedal bikes for a while now. Zip tie, front chain guide and all.
https://www.pinkbike.com/news/review-in ... sting.html
Very expensive, and very noisy. But mid drive users get this for free.

[neptronix]

Hey all.. gave ebuilder the boot and accidentally nuked his posts..
context on this thread will look funny; sorry about that!

[Retrorockit]

I'm still riding this mod and learning how to make it work better.
It wants to push slack into the top chain run when downshifting. Any friction there makes it worse. So no friction type chain guides.
A modern clutch type derailer (Sunrace M900 for 8-9 speeed, Box makes some also) with a heavy spring will probably help pull slack out from there. But I want to keep my vintage Rapid Rise XTR stuff.
My bike is probably a worst case scenario in a lot of ways. My chainline is 60mm with a flat 50t chainring on a 1500W BBSHD.
With Rapid Rise and a gripshift I can throw a lot of gears up and down at once.
I came up with a bolt on chain guide solution that lets me use full power in all gears. I can't provoke any issues running it up ( and down) on the center stand, and I have about 100 real world miles on it.
I'm using parts for recumbent chain management from Terra Cycles.
This is the clamp. It's listed as 36mm. It fits a 34.9mm painted seatpost just fine. Very versatile bracket. 8mm Allen bolt for a shaft.
https://t-cycle.com/products/5-hole-ver ... ain-widget
This is their drive side 15t idler cog I used for a roller chain guide. Smooth and quiet.
https://t-cycle.com/collections/idlers/ ... r-idler-15
I run it to the rear of the chainring, and close enough that the deep sides overlap both cogs. The offset clamp let me avoid some bottle mounts,and a torque arm mount on the other side of the seatpost. I needed the furthest hole, and used the slotted adjustment too. I tried a lot of rollers in a lot of positions with this bracket.
If you have a big wheel bike with a tiny chainring they make bigger 23t idlers that may work.
They offer a chain keeper pin for these. Don't use it with this mod. The minute the chain touches it huge slack shows up from the drag there.
I'm using 2x tiny zip ties now. I've broken them a couple times. But no big deal I just carry a pair of tweezers and a couple ties in my tire patch kit. I'm hoping I can get them to last more than a couple weeks. I mostly broke them downshifting 5 gears at once from 32mph.I used to do that routinely with Rapid Rise since the shift didn't actually happen until I pedaled it into gear just before stopping. With this mod the shift happens in real time. It wasn't really necessary to shift like that anyway. If I need to throw down a bunch of gears with the brakes locked up the Rapid Rise will still allow the shift as before.

[Retrorockit]

There is a German distributor for Terra Cycles.
https://www.icletta.com/en/kontakt.en.html
Terra Cycles US site refers all German inquiries exclusively to them, but will accept inquiries from all other countries. IDK how this would work out for other EU users but they do have a presence there.
I don't see the 5 hole adjustable bracket I used listed there.
I have no association with them (or any other company).
I'm still working my way up to testing this harder and harder. if I run it up to 35mph on the center stand I can get some chain slap on they stay if I dump 5 gears suddenly, but no derailment. If I roll down through the gears I can drop all 8 cogs at 24mph with no problem.
There is no reason to ever do this while riding. For streeet use I never use the 2 lowest cogs anyway. 11-40t cassette.
I've also hucked it off of a curb at the same place I had my last chain drop and nothing happened.
There is one place where I can safely ride 30mph and look down at my chain while braking and I saw no issues. It's a 10' wide concrete path with solid concrete crash barrier on one side, and a concrete sound abatement wall on the other. Almost never any other users around.

[Retrorockit]

With this chain management setup I can use full throttle in my crosschained 2 lowest gears. This can lift the front wheel of my 72# E bike.
Here is an example of the kind of problem the zip tie mod can solve.
A few times my bike when accelerating through left turns would break the Connex link on an upshift and lose the chain. Not a chain drop, it would leave the bike completely in traffic.
My first solution was to rivet the chain. Now it would just drop the chain, so a simple chain roller at the top was good enough most of the time. But I still had bent teeth in the middle cogs on the cassette from the hard shifts. This was due to the bike being leaned over in the turn, so I couldn't pedal, but needed the upshift to stay clear of following traffic (or oncomimg). My chainline is actually very good in those gears. With the front freewheel mod those shifts are very smooth and silent with no damage at all.
This mod does push more slack into the top run of the chain under some conditions. Multiple gear shifts are one of them. it's possible to get ahead of the derailer return spring with my vintage Rapid Rise setup. The Terra Cyles cogged idler has taken care of that problem.Newer clutched MTB derailers would be better also.

[Retrorockit]

I've got some more time in on this setup with the recumbent chain management parts. I can now do wheels up launches in my 2 lowest cross chained gears. This was never possible before. No chain drops, or broken zip ties either.
Due to my age and flat terrain here offroad use hasn't been tested. But the magic cranks version of this mod for MTB has been tested on Canada's Vancouver island and was well received.
For my fast street E bike I'm running a gripshift and vintage Rapid Rise derailer for multiple shift capability.
For offroad a trigger shift and clutch derailer would probably be better. There is also a 23t option on the toothed idler that might be needed for smaller chainrings and bigger wheels.

I hope the 20 people a day that are viewing this enjoyed it. 2500 views and counting. A little surprised that there are no comments or feed back from people who tried this. But considering how this thread started out I guess it's better this way.
I think this mod is at a point where anyone who is interested can try it and have success with it.
I used a 50mm X 8mm Allen bolt for a shaft. That size has enough bare shank for the 2 bearings to sit on, and is long enough for just about any chain line (even mine). A lock nut, plastic spacer, and a washer or 2 to line the idler up are all that's needed for this.

[Retrorockit]

Just a thought on derailer cage length for this. I selected a mid cage derailer before doing this mod to match my 11-40t cassette. While cleaning the chain to lube it the rag would go into the idler and stop the chain. The derailer would wind up, and then unwind turning the wheel backwards. Obviously that can't happen if the bike is moving.
Since slack IS going to be forming sometimes in the top of the chain it would probably be better if the derailer cage had some extra capacity to absorb and release it. So a long cage derailer may be a better choice for this. Since I'm not having any issues at this time I'm not going to test this theory. But this might be what was going on when I stuffed it into the big cogs at 30+mph. By using up the derailer capacity the zip ties would break without any chain suck happening. Just a theory.

[Chalo]

That's no downside to having more rear derailleur wrap capacity than you need, unless ground clearance is a factor (which is rare). But things can get very bad if you need more capacity than you have.

With an 11-40 cassette, there's enough rotational inertia that you'd benefit from a clutched derailleur, to help keep the heavy cassette from spooling slack chain over the top when you stop pedaling suddenly.

[Retrorockit]

For fast street riding I want the Rapid Rise- Low Normal derailer, and Gripshifter. These haven't been made since the 8-9 speed era.
I bought an M900 Sunrace clutch derailer. But everything is working now as long as I downshift at sane speeds. I bough the mid cage M900 because I hadn't observed the need for extra travel yet.
On a 26" bike the mid cage ground clearance could be useful If I get squeezed up against a curb in traffic. Or cut a corner too tight.
But for other users in other situations a long cage clutch derailer would make sense.
The need for an extended derailer hanger to use the Vintage RR derailer with a wide range cassette is a factor also.
I converted a bike that i've owned since 2004. So many vintage parts like BB7 brakes and rapid Rise were already there, I haven't found any reason to get rid of them.

[Retrorockit]

To understand what's happening with this mod.
1- The force pushing the chain forward over the top is the entire weight and velocity of the bike and rider acting through the wheel.
2- The limit to the actual force applied is the strength of the small zip ties. You control this. When they break the bike returns to normal.
3-The resistance to this force is the drag of the front freewheel and any chain control device. This plus #2 creates intermittent slack.
4- The control of the slack comes from the tension applied by the derailer to take up the slack. Newer clutch type derailers will be better at this. There will typically be some delay in this action. This can be observed running the bike on a stand.
5- The chain control device performs the same function as the derailer cage to guide the slack chain onto the cog. In this case the front one. If it adds drag it will increase the slack.
If the zip ties are breaking there is a problem. In my case it only happened when downshifting 5 gears at 30mph. At 20mph no problem. A clutch derailer may have been another solution, or longer derailer travel to absorb the downshift and resulting slack.
But good chain management is required.
Since most people don't have a shifter and derailer that can dump 5 gears at once not pedaling............
This bracket.
https://t-cycle.com/products/5-hole-ver ... ain-widget
And this idler.
https://t-cycle.com/collections/idlers/ ... r-idler-15
Are the parts that worked for me.
I'm not associated with any company.

[Retrorockit]

Here is another guy doing this with a piece of foam behind the freewheel or cassette to provide clutch action instead of a breakaway solution. You could probably find an O ring that will fit for this purpose also. He's not doing mid drive E bikes so IDK what he's using in front.
https://www.instructables.com/Modern-po ... cycle-FFS/
So if your bike is blessed with a dork ring........................
I like the breakaway for testing because it keeps you honest about chain management issues. But perhaps another option might suit some riders better. You can always grab the cogs with a rag and test the force needed to release the chain. The breakaway does have the advantage of going to zero force immediately. It definitely works.If i dropped a chain when testing this it just sat there not moving.

So a little history on this.
50 years ago Shimano offered this, but chain management was just a 2 speed derailer cage. Youtube videos make fun of it, but they don't mention riding it. In the comments people who rode one liked it. I think Rapid Rise low normal derailers won out because they were interchangeable with existing bikes. I still use them for 1x8 bikes.

Magic Cranks still offers Front Freewheel with zip ties, and requires a chain guide, but they don't get specific about what's required there.
It very expensive and noisy also.

Mid rive E bikes make this an option again for anyone who is interested. Front Freewheel is already there. Modern MTB derailers, and recumbent/ trike chain management solutions didn't exist 50 years ago.

[Retrorockit]

I had feedback in another forum that one user's bike had the pedals move when pushing his bike and it took off on him. I had just lubed my BBSHD before doing this, so my pedals don't move. Test to be sure your front freewheel is working properly. The rear one can cover up maintenance issues here. It didn't help that he was parking his bike with full power selected.
I might add that the freewheel pawls don't take the heavy grease that the gears require. It would just make them sticky and get in the way of them moving. There is no motion there when it's engaged so very light grease will do. The same applies to the roller clutch inside the plastic gear.

[Retrorockit]

I happened to put a smaller cassette on my bike (not related to this mod) and decided not to shorten the chain. So another variable is chain length. It doesn't matter if you have a longer derailer cage if you take out all the extra travel by cutting the chain to the minimum length. So look at derailer capacity and if you have a bit extra maybe leave the chain a little long so slack can come and go in the lowest gear. DIY bikes are going to be all different. They may respond to this mod in different ways. But mine is definitely working.
FWIW I threw it into low gear on the center stand @ 38mph and nothing happened.Changing the cassette required me to cut the zip ties. I really wanted to see how long they would last.(Low is now 36t instead of 40t)
3000 views coming up on this thread soon. I hope you guys are enjoying this

[Retrorockit]

This mod seems to be at the No News is Good News stage of development. I haven't broken a zip tie in a while. The chain management solution to tame the dreaded Zip Tie Mod has also tamed my cross chained BBSHD. I'm just riding the bike now.
Since I can use all gears under full power I've redone my cassette.
My secret gearing is.
11-12-13-15-18-22-28-36t x50t it started as a Sunrace 11-40t 8 speed, Lost the 40t and gained a 12t. Then the 34t got replaced by a 36t that came with plastic spiders between the cogs. Probably a good idea for my setup. A parking incident broke my extended derailer hanger. The cassette mod got me going with the stock hanger. The modded cassette was already sitting on the shelf.

[Retrorockit]

Still no problems to report. Since this mod makes throttling around not pedaling, and running up through the gears like a motorcycle easy ( even zooming around standing up in the breeze not pedaling). I was experiencing some loss of range concerns. Also it doesn't coast as freely pulling the chain around all the time. With a 24Ah battery range testing is a bit of a chore. But riding normally I can get my expected range. Normally for me includes full throttle takeoffs in traffic and a couple bursts to 30mph. But mostly 15mph PAS1/5 and 20mph PAS2/5 riding. Strong headwinds here require PAS3/5 or even 4/5 and really consume the battery, so I had to wait for a still day to do this test. I din't get too technical with this. A 36 mile loop the 4 bars on the display dropped 1 bar 1/3 of the way back, and only dropped the 2nd bar 1/2 mile from the end. My 18Ah battery never made it to the turn around w/o dropping the first bar, so it's about the expected range. Living near the ocean range is always negotiable anyway.
Something I noticed on the test stand is that when running up through the gears using the throttle, when you upshift lifting the throttle (coasting to shift) and moving to a smaller cog always puts some slack in the top run of the chain. Multiple gear upshifts cause more of this. 2 gear upshifts are actually pretty common for me. The motor has enough RPM and enough low end torque that shifting up 2 at once saves an extra shift that can confuse following traffic. Also the motor can go 140RPM and I can only do about 100. I need 2 gears up to get back to the range of my own cadence. So full throttle launch, 2 gears up for momentum, and 2 gears up for cadence is common. With the recumbent chain management this has not been an issue. It's possible that this was one of the situations where I previously had zip tie breakage that the cause wasn't specifically known. This is a situation where the strornger clutch type offroad derailers may help. Since I'm all vintage Rapid Rise/ Revoshifter, and not having any issues, I'm not going to test this myself. Who knows maybe some users won't need the extreme chain management solution that I do.
I didn't get very technical with the battery measurement because I never bothered to do that before, so no really accurate comparison was possible.

[Retrorockit]

I really can't tell much either way on the range issue. I'm sure it hasn't improved, but using some Ebike range calculators it seems to be well within reason. Another issue is that I recently added a Tannus Armour foam tire liner to the rear tire. That thing adding weight and squishing around back there can't be helping range either. But it's doing so much more I'm going to keep it. I've pedaled this bike with a flat battery and honestly it's a pig. I'm covering up for this with a big motor and a big battery. That's the American Way I guess. So if efficiency is an issue for you you're on your own here. I've had women tell me my bike looks like something out of Mad Max. So Road Warrior it is.
I've also pushed this bike with a flat tire. I prefer pedaling the pig.

[Retrorockit]

Here is a link to a photo of the recumbent idler as a chain guide. It catches the chain in mid air and sticks it down on the chain ring.
I have it further back and further down now. No possibility of spacing the 50t ring in further. This is the 15t size, there is a bigger 23t option.

https://lh3.google.com/pw/AMWts8Bs0pTzH ... authuser=1

[Retrorockit]

Here is the photo itself. You can see the flat 50t chain ring, and the 15t idler that runs smoothly on the chain all the time. It catches the chain in mid air and sticks it down onto the chain ring. No friction because it's turning with the chain. I'm actually running it further back and lower to get more wrap on the idler. The reason for the change from the photo was the method of adjustment used. They both started with the idler all the way back. The first try I used the slotted bracket to move it forward to touch and then away. This was a little difficult because the shaft needed to be removed to access the slotted bolts. After thinking about this I decided to put the idler all the way back again, and adjust it by raising and lowering the seatpost clamp. This was simpler and kept the idler further back, and lower to engage the chain sooner.
Basically it's a jockey wheel just like the derailer has to put the chain where you want it.