Mid drive front freewheel mod.

[Retrorockit]

No the freewheel in the cranks of the BBSHD , and the one way clutch [n the pinion gear itself prevents that. It just locks out the rear freewheel to allow shifting w/o pedaling ( or with it as before). The 2 remaining freewheeels allow the pedals or the motor to go faster than the other depending on which one provides more power. The bike can shift like an Internal Geared Hub, but keeping the chain on can be tricky. I figured out how to do that. But getting parts strong enough for a BBSHD is the hard part.
Just getting the chain to behave when coasting is a problem, actually trying to send power forward from the rear wheel to charge the battery would be very difficult ( I don't like the word impossible). This could be designed into a mid drive at the factory, but it's not likely to happen on a DIY conversion.

 

[Retrorockit]

T-Cycle was nice enough to replace the broken part. It was and still will be a useful fixture for fitting their idler to other bikes, and some light testing.
The band of the clamp is no bigger than any other similar seat post clamp with 2x5mm bolts. It lasted 2 weeks on my 1500W bike. On a 350W bike it might be OK, or you could drill it out for 6mm bolts. But it's the thin strap at the bracket that broke, not the strap across the back. The 15t idler is amazing. I really miss having it on the bike. I may take the broken bracket to a welder, and have some extra metal added. To be fair it wasn't made for this, but so far no simple off the shelf solution yet.
Getting back to DIY territory I ordered a T-Cycle battery supportt clamp in 1.375" (34.9mm) Thicker (5/8") material and bigger strap and M6 bolts. So they do know how to make Ebike parts when they want to.

Frame Clamp

The heaviest duty clamp we offer! It's the clamp that holds the Battery Mounts, the SPRING Mini Fairing Mount and the WINTR Fairing Mount in place! Sporting twin 6mm bolts, this 5/8" thick beast stays where you put it and holds what you need it to hold. Made in an ever-growing list of sizes...

t-cycle.com

You have to look in their a la carte section to find these. Some are for square tubing so don't let the illustration photo deceive you.
Functionally this is doing everything I ask of it. Structurally it would be nice if it stayed on the bike a little longer.
So the update is.
The zip tie mod works but needs serious chain management to go with it.
The T-Cycle 15t idler handles all kind of chain issues. But the bracket to use it for an Ebike chain guide doesn't exist yet. At least not at BBSHD levels.

 

[Retrorockit]

A little progress while waiting for parts. I took some of the stuff that didn't work so well and installed 2 different small roller guides at once in tandem. Seems to be working at reasonable power levels. I know it won't stay adjusted under full power launches So the bikes not parked. The 2nd one is on an arm clamped to the head of the Allen bolt holding the first one. None of these parts were intended to be used together.
One of everything=one of "something".
Aaron at T-Cycle was kind enough to send me the dimensions of the HD Battery Bracket so I can make my chain guide conversion adapter plate while waiting for parts. 2xM6 bolts 1.97" apart. I like the wide spacing, good leverage on the bracket. I'm going to test it as sold to see if there is a one stop shopping solution for this.
But it could be drilled & tapped out to M8 for maybe a wider Fatbike installation if needed.
There is another version of this same clamp for attaching fairings to trikes. I didn't think to ask what the difference is. probably something to do with the bolts.

 

[Retrorockit]

One other option for this 15t idler is a 10mm bearing. At the width I'm using the M8 bolt makes sense because I've bent them before, and it's a simple repair to just relalce an M8 Allen bolt. Like the zip tie it's nice if nothing ever breaks. But it's also nice to be able to fix it easily if it does. But if you need to go wide it's an option.

 

[Retrorockit]

I got my replacement for the broken clamp, and the bigger one also. I put the replacement on and watched it under power. Every time I hit the throttle the clamp flexes. The new clamp is much stronger. It's designed to hold a 15# E bike battery on a 6" arm at any angle. It has 5.5x the cross section where the other one broke. I made my adapter bracket too long while waiting for parts so I had to cut it down and start over. The new bracket and the 3/8"x1" adapter are on and nothing is wiggling around anymore. 100% function again. I may have overtightened the bearings by not using a jam nut like I did last time. The price for the big clamp and the small one are the same. The 5 hole bracket is extra. The adapter is 3/8"x1" 6061. The offset on the holes is so the clamp will clear a water bottle mount on my frame, and a BBSHD torque arm on the other side. many bikes you could probaly put the holes in line and centered.

 

[Retrorockit]

I got a 30 mile ride in last night, no issues. This morning I took a fresh idler and set it up with 2 jam nuts like a bicycle axle. It rolls much smoother. Then I replaced the Allen bolt behind the idler with a hex head. It can be unscrewed all the way, and the adapter can be swung up off of the chain, and the idler and shaft can be removed as an assembly without disturbing the bearing setup. I've been looking for a reason to call this the Rockin' Roller., now I've got one.
Rode it again today about 25miles. 20MPH winds gusting to 25. changing direction quite bit too.
I'm making a couple other adapter plates to see if I can get a little more wrap around the idler. One will sit level on the seatpost.
This was at the point of just riding it around until the mounting bracket broke. I think I've got that solved now.

 

[Retrorockit]

So, just a reminder, this is not the 15t idler bracket repair thread. It's the Mid Drive Front Freewheel Mod thread (Zip Tie Mod). That part is working perfectly again.
So here is an update to have it all in one place..
1- Mid drive Ebike conversions have a freewheel in the pedals. The rear one isn't really needed any more. Clutch at the motor is normal car and motorcycle practice.
2 This has been done in the past and present by Shimano and others (Magic Cranks). Sometimes with special cassette/freewheels. More recently breakaway Zip Ties at the hub to eliminate the rear freewheel action. If the chain hangs up the Zip Ties break, and the bike returns to normal.
3-This allows multi gear up and downshifts any time the bike is moving without pedaling (or with). A twist shifter helps make this possible. Just like a car throwing it into low gear at full speed can cause problems (broken zip ties LOL)
4- Drive side chain management needs to be improved for this. Basically a stationary jockey wheel to guide the chain onto the chain ring just when there is slack there, just like the rear has. Low friction is critical here. Modern clutch type derailers with heavy return springs should help, but I don't have /need one. There are recumbent parts that work for this.
I'm not sure there will be much more to this thread. I think it's at the point where just riding the bike comes next. I have a couple incremental improvements to the home made adapter to try. And the bearings in the Idler need to be treated with care and set up with 2 jam nuts like front axle bearings, not just tighten the bolt like an automotive idler assembly. I put a hex nut on the bracket behind the idler so it can be released with idler in place, and the adapter swung up to clear the chainring for service. The idler and shaft can be removed together without disturbing the bearing setup. Because of this I can now call it the Rockin' Roller.
Over 3600 views on this thread. I know that not quite that many people are interested, but it seems the ones who are stick with it.
I have no connection with T Cycle or any other company But I'm very happy with their recumbent parts. Even the one that broke. It was versatile enough to let me test this idler, and several others, on my bike to see what actually worked best.. I hope you guys are enjoying this.

 

[Retrorockit]

I forgot to mention in the summary.to leave a little extra chain length in the biggest cog. On my bike I can push the chain down to the chainstay and not run out of derailer travel with a 50t chainring.
The travel of you derailer is not what it says on the spec. sheet if you cut the chain to the minimum length. Medium cage will often be enough.
The zip tie mod does push slack into the top of the chain. If there is travel available in the derailer it gets absorbed and released there. If there isn't travel to do this then the zip tie s break even though there has been no serious chain event.
1 link (or1") equals 4t cog size, so you can use that to calculate derailer capacity needed for your bike.

 

[Retrorockit]

So there's literally a break in the action. The BBSHD broke the first 15t idler clamp. I've got that resolved and now the motor shaft has broken in the BBSHD. Probably from wheels up launches testing the stronger chain guide. The failsafe breakaway zip tie is just fine. I had the older BBSHD that can sometimes do this. The newer part has a larger shaft , and a couple stress risers have been moved away from each other. California Ebikes says you can put a conversion bearing on the newer shaft and use it the old motor, others want to sell a whole motor. Of course I will try the bearing swap and see what happens.

 

[Retrorockit]

I had one user in another forum report that he's had no chain management issues with a modern Shimano M8000 derailer, Wide/Narrow chain ring, and good chain line. He likes the stealth of no ratcheting sound, but he still pedals when shifting and says when the zip tie breaks he probably won't replace it. But that hasn't happened yet. He's a high mile desert rider on a BBSHD fatbike. He also has a shift sensor which I don't use.So a lot of what you see here is just me taming my street rat Ebike. So some bikes it's just a zip tie or two. I had another guy with an older 7 speed bike give up on it right away. I suspect there is something sticky in his derailer causing problems. So some bikes take to it better than others. Some riders too. But that's kind of normal in the bicycle world.

 

[richj8990]

Shimano.

Or the zip tie breaks.

To a large extent my wheels, brakes and driveline are old school DH racer parts.
In theory, theory and practice are the same. In practice they are different.
Engineering IS done with very little invention.

What would this zip tie mod do (in theory) if there were absolutely no freewheels in the drivetrain at all: none inside the motor housing, none up front on any chainwheel / crank axle / crank, and with a cassette none of course in back. I know the BSSxx has some type of clutch inside, but if there were no freewheel/clutch inside the motor...

 

[Retrorockit]

If it had no freewheels at all (there are actually 2 inside the motor) it would become a fixie. The cranks would always turn with the wheel.
I'm not sure I see any real use for that, or fixies in general.
There is a 2nd way to do the rear freewheel mod. I saw this an a bike with a n actual freewheel. An O ring or washer of some material was installed between the cogs, and the hub, or even a dork ring to provide a slipper clutch effect. Thiis very much like what Shimano did, and wouldn't require replacing a zip tie. if it did slip occasionally it would distribute the wear between the pawls better.

 

[richj8990]

If it had no freewheels at all (there are actually 2 inside the motor) it would become a fixie. The cranks would always turn with the wheel.
I'm not sure I see any real use for that, or fixies in general.
There is a 2nd way to do the rear freewheel mod. I saw this an a bike with a n actual freewheel. An O ring or washer of some material was installed between the cogs, and the hub, or even a dork ring to provide a slipper clutch effect. Thiis very much like what Shimano did, and wouldn't require replacing a zip tie. if it did slip occasionally it would distribute the wear between the pawls better.

Sorry I don't think I explained the question well if you think it would turn the bike into a fixie.

A fixie from what I've read is a single-speed one chainring one cog in back. No shifting, ever.

What I was asking is for something that has one chainring in front, a real cassette in back (11-speed), where there is shifting. But there is no freewheel / clutch anywhere preventing the live motor from turning the cranks when active. I did not mean lack of a threaded rear axle freewheel in back where in the 21st century all geared bikes should now be at least an 8-speed cassette. I mean a clutch freewheel in front, either in the motor, on the crank axle, or on the crank(s). If that's gone, what would the zip-tie do.

Would a zip tie in the rear wheel help that situation at all if the chain got hung up but the pedals kept turning accidentally, say if the rider didn't let off the throttle in time.

 

[Retrorockit]

It would be a multi speed fixie. No freewheel the pedals will always turn with the wheel no matter what gear tiy're in. I understood it. I just don't see the point.

 

[richj8990]

It would be a multi speed fixie. No freewheel the pedals will always turn with the wheel no matter what gear tiy're in. I understood it. I just don't see the point.

The point is that I'm not tied down (no pun intended) to heavy, outdated square-tapered bottom brackets and cranksets, not to mention that added weight of wherever the freewheels are located on those. The point is to bring the e-bike into the 21st century for the crankset. And not have a Walmart $50 crankset on a $2750 bike. That's the point.

 

[Chalo]

The point is that I'm not tied down (no pun intended) to heavy, outdated square-tapered bottom brackets and cranksets,

Do you mean proven for generations at the highest levels of competition? I think that must be what you mean.

I've broken a couple of square taper spindles, but I'm the size of two cycle gladiators and I was quite strong in my day.

Structurally, big diameter spindles make more sense, but nobody has yet come up with bearings for them that equal the endurance of the ones in square taper BBs.

I use "heavy, outdated" BMX 3-piece cranks for most of my bikes. 19mm and 22mm solid CrMo steel spindles.

 

[Retrorockit]

I'm pretty sure this thread isn't about square tapered bottom brackets. I could see how locking the cassette to the spokes might segue into fixie bike topics.

 

[richj8990]

Do you mean proven for generations at the highest levels of competition? I think that must be what you mean.

I've broken a couple of square taper spindles, but I'm the size of two cycle gladiators and I was quite strong in my day.

Structurally, big diameter spindles make more sense, but nobody has yet come up with bearings for them that equal the endurance of the ones in square taper BBs.

I use "heavy, outdated" BMX 3-piece cranks for most of my bikes. 19mm and 22mm solid CrMo steel spindles.

Well 26" tires were proven for generations too, but you are not going to see them very much now offroad. I do agree that 26x4.0 is fine for a fat bike w/o suspension. 2.5 or below is simply not going to cut it offroad when things get chunky.

Clipless pedals were 'proven' offroad for a long time back in the day, but unless someone is in a race and wants to win some 30-mile competition by 20 seconds, all they do is keep you glued to the bike during a crash. And on a 50 lb e-bike, that could be really dangerous. They also contribute to knee problems because there is no 'rest' during the pedal's upswing.

Old habits die hard. Including the square-tapered spindle. Hey, if someone is using 2000W and they need heavy-duty parts, so be it. Modern cranksets can be had now for not much over $100 USD and they are about 10 times easier to work with. Not to mention significantly lighter. Again, if you need heavy-duty parts, I get it. I don't need them. I need something that's lightweight and efficient, and if there is a problem, I can fix it in 10 minutes with lightweight tools I have in my pack.

I see these $2500 e-bikes out there for sale with mid-drives, looking at the components to see if the whole bike is worth buying or not. Almost every time I see that they come with square-tapered cranks and quick-release wheels. Look...I'm still riding a bike like that. Eventually I'll donate it, throw it in the trash, or put it in some friend's garage or something. Yes I still ride those kinds of bikes. But even for an e-bike...modern, lighter parts can make a real difference over the course of the bike's life. You may have a blast for a while with a heavier e-bike that has cheap/old components, but after a while someone like me grows tired of their problems and the inability to upgrade them, as in thru-axled wheels. If someone can live with those older parts, great. I want to emphasize that I'm not advocating everyone to buy a $10,000 e-bike. Just saying that it doesn't cost much more money to get components that are newer, efficient, user-friendly, and lighter weight.

 

[Chalo]

Old habits die hard. Including the square-tapered spindle.

I used to be one of the most zealous evangelists on rec.bicycles.tech against the square taper bottom bracket, predicated on my traumatic experience with them. Now into my fourth decade as a bike mechanic, I know they're simply less trouble than the alternatives for most people, most of the time. Full disclosure-- I rarely use one, and only the nutted type that aren't drilled out at the point of highest stress. But typical threaded BB shells accommodate those spindles with bearings that work long and well, and big spindles don't allow that.

I believed in external bearing cups-- even made my own from scratch before Shimano did-- but time and experience have demonstrated they don't equal traditional BBs for longevity and reliability.

Haven't tried a T47 frame yet, but I really don't want to tool up for one.

 

[Retrorockit]

I've upgraded the front freewheel mod. But only after getting the bugs out with the zip ties. I went to a 3/16" square Oring with silicone grease behind the cassette so it wont get stuck. It will turn with 1 ft$# of torque, and reaches 3 ft# when spinning. Some bikes have spacers behind the cassette and all hubs may not be the same as my XT. I tried some round rings, but went with the square because the round ones might flatten out over time. Shimano did something like this with the original front freewheel system, but did each cog separately. This just does the whole casette at once. I went with a Shimano CS HG400-8 11-40t cassette with the 2 low gears riveted together and even 22% splits in the mid gears. It's working OK with a longer B screw on my XTR mid cage derailer. Rapid Rise lives!

 

[Retrorockit]

I used to be one of the most zealous evangelists on rec.bicycles.tech against the square taper bottom bracket, predicated on my traumatic experience with them. Now into my fourth decade as a bike mechanic, I know they're simply less trouble than the alternatives for most people, most of the time. Full disclosure-- I rarely use one, and only the nutted type that aren't drilled out at the point of highest stress. But typical threaded BB shells accommodate those spindles with bearings that work long and well, and big spindles don't allow that.

I believed in external bearing cups-- even made my own from scratch before Shimano did-- but time and experience have demonstrated they don't equal traditional BBs for longevity and reliability.

Haven't tried a T47 frame yet, but I really don't want to tool up for one.

I don't ride offroad. Old obsolete 26" MTBs with BB7 brakes, solid wheels, and short travel forks go for about $250. They make great street e bikes. Strong and good handling. If the bike has BB7s the rest of the components should be good also. With metallic pads, and big rotors (especially Shimano ICE) they are up to the task. There are 50kph rated street tires in 26x2.15 that work well for this. For offroad the world has turned. Probably several times. But obsolete MTBs make good donor bikes for Ebike conversions.

 

[Retrorockit]

The 2 advantages splined BB have over Tapered is that they can be drilled out to remove the dead weight from the center of the shaft. On my XComfort bike with XT cranks and hollow bolts I can see all the way through them. Also the same bolt and Allen wrench you put them on with can extract them. But the square taper is working just fine on my 65# BBSHD road burner.
So is the revised zip tie mod with friction ring.

 

[Chalo]

The 2 advantages splined BB have over Tapered is that they can be drilled out to remove the dead weight from the center of the shaft. On my XComfort bike with XT cranks and hollow bolts I can see all the way through them. Also the same bolt and Allen wrench you put them on with can extract them. But the square taper is working just fine on my 65# BBSHD road burner.

Hollow spindles are a privilege of large spindle diameter, not the crank fixing method. Sugino Magnera cranks from days of olde had large diameter square taper spindles that were bored out. Likewise there have been many splined spindles that were solid, either because they were small in diameter or because strength and stiffness were more important than light weight. For decades my go-to crank has been Primo Powerbite, which features a solid 22mm diameter chromoly spindle with a non-tapered square interface.

Self extracting crank bolts and caps have been a thing for much longer than splined cranks have been popular. Campagnolo and Shimano both produced plenty of such cranks with square taper spindles.

 

[Retrorockit]

Maybe Endless Sphere is dying because threads get crapped up with off topic nonsense that nobody cares about?
Why don't you start a square tapered BB thread for squares.

 

[Chalo]

Maybe Endless Sphere is dying because threads get crapped up with off topic nonsense that nobody cares about?
Why don't you start a square tapered BB thread for squares.

Hey, you brought up the topic. I just fact checked you because what you said wasn't accurate.