Still having that clanking noise .. ready to give up.

Greg47

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I built a couple mid drives last year using Bagang units. One 250 & a 750 fat bike for the woods. The Fat tire makes a clanking mouse intermittently that bugs me. It’s loud and is coming from the back. Only works when the power is on, not manually pedaling or coasting. at first I thought it was just the clunky nature of the freewheel style hub I had on it, but changed to a cassette rear wheel; no change. Have changed the sprocket front & rear (7sp), chain, display. Tried adjusting everything several times. Using an egg rider that I programmed according to one expert.
im beginning to think the motor is pulsing? Could it be the controller?
this is a ”stealth” bike for slipping around the woods, because this old man can’t walk like I used to.
any input appreciated.
Thanks,
Greg
 
Since they are mid drives, and the noise is coming from the rear hub, its not happening in the motor. Thats a normal bicycle wheel.

I am guessing that what you are hearing is the motor engaging so hard it is making the pawls clunk inside the rear hub mechanism. What you want to do is get your programming cable out, fire up the Speeed app on your phone (or your EggRider app) and
  1. change the setting for Start Current on both the Pedal Assist and Throttle screens from whatever it is to, say, 5. I personally go as low as 2.
  2. Next, on your Pedal Assist screen, set the Slow Start Mode to 3 and no lower(!).
  3. Last, on the throttle screen change Start Voltage and End Voltage to 11 and 42, respectively.
What this will do is lower how hard the motor yanks on your chain, which in turn will lessen dramatically the bang on the rear cluster. When you pedal, the initial bite will also be lessened, and power will ramp up more gently. And when you hit the throttle for a manual boost, the increased range will turn it from an on/off switch to something you can modulate power in gradually and gently if you so choose.

This article goes a long way to explaining these and the other settings.

 
Since they are mid drives, and the noise is coming from the rear hub, its not happening in the motor. Thats a normal bicycle wheel.

I am guessing that what you are hearing is the motor engaging so hard it is making the pawls clunk inside the rear hub mechanism. What you want to do is get your programming cable out, fire up the Speeed app on your phone (or your EggRider app) and
  1. change the setting for Start Current on both the Pedal Assist and Throttle screens from whatever it is to, say, 5. I personally go as low as 2.
  2. Next, on your Pedal Assist screen, set the Slow Start Mode to 3 and no lower(!).
  3. Last, on the throttle screen change Start Voltage and End Voltage to 11 and 42, respectively.
What this will do is lower how hard the motor yanks on your chain, which in turn will lessen dramatically the bang on the rear cluster. When you pedal, the initial bite will also be lessened, and power will ramp up more gently. And when you hit the throttle for a manual boost, the increased range will turn it from an on/off switch to something you can modulate power in gradually and gently if you so choose.

This article goes a long way to explaining these and the other settings.

Ok I tried that and a bunch of different settings. Any that gave enough assist, had the same noise or louder. At the very low setting (5) an lowest gear, it was quieter, but felt like no assist at all.
I definitely need it on this fat tire off road bike (I’m 76 also). I tried raising the numbers a few at a time, and as soon as there was noticeable assist, the clanking came back.
Could the motor be bad and pulsing power to the sprocket causing that noise?
I can’t even replace the unit as no one here had the long axle frame tube for the fat tire frame. Had to order it from China.
 
Well, what you are describing certainly isn't normal. One thing to remember is the settings are interdependent, with zero documentation from the factory. Its all been just 'figured out' by the user community.

I suggest you publish all of your settings. Screen shots of the software. Otherwise we're kind of firing blind here.
 
Well, what you are describing certainly isn't normal. One thing to remember is the settings are interdependent, with zero documentation from the factory. Its all been just 'figured out' by the user community.

I suggest you publish all of your settings. Screen shots of the software. Otherwise we're kind of firing blind here.
I can do that. Have you seen control settings cause this kind of clunking sound?
The other one I built for my wife on her Scwinn mtn bike is perfectly quiet and smooth.
If you program settings with the egg rider, do they stay in the controller if you change displays? I tried the original bafang display with no luck.
 
I can do that. Have you seen control settings cause this kind of clunking sound?
Only the ones I described above, which will definitely cause a clunk from basically hammering the power onto the drivetrain.
If you program settings with the egg rider, do they stay in the controller if you change displays?
Yes all Bafang programmers just read what the controller has inside and let you change it. Hopefully for the better.
 
Try setting a recording device stationary and low to the ground, ride past it multiple times. Post a recording of the sound.

Does this EVER occur on smooth pavement, test this extensively.

Make some strenuous pedal-ONLY efforts with the motor OFF. You should be able to replicate the same stress on the chain and rear hub. You should get the same noise. Maybe borrow a younger person, do not over-exert yourself.

Do some repetitive testing, a LOT of it. What, EXACTLY, is going on when the noise occurs, and what is happening when it does NOT.

For instance, you have mentioned it happens with hi levels of assist, and not with low. Well, at a hi assist, you are likely moving FASTER. Any bumps would jolt the bike harder. A loose part somewhere would make more noise.

Have you looked Real Hard and Real Careful at the motor mounts? You have asked about pulsing several times, motors generally not do that, but a loose mount could vary the chain tension, and cause something very similar.

When it "clanks", is it just ONE clank, 2 or 3, several dozen, what? Does it repeat, if so, a fraction of a second interval, 1-2, 5-6, describe.
 
Just a wild guess, but you might check the tension on all your rear spokes. I was having an similar noise on my rear tire and I eventually found some loose spokes.
 
Try setting a recording device stationary and low to the ground, ride past it multiple times. Post a recording of the sound.

Does this EVER occur on smooth pavement, test this extensively.

Make some strenuous pedal-ONLY efforts with the motor OFF. You should be able to replicate the same stress on the chain and rear hub. You should get the same noise. Maybe borrow a younger person, do not over-exert yourself.

Do some repetitive testing, a LOT of it. What, EXACTLY, is going on when the noise occurs, and what is happening when it does NOT.

For instance, you have mentioned it happens with hi levels of assist, and not with low. Well, at a hi assist, you are likely moving FASTER. Any bumps would jolt the bike harder. A loose part somewhere would make more noise.

Have you looked Real Hard and Real Careful at the motor mounts? You have asked about pulsing several times, motors generally not do that, but a loose mount could vary the chain tension, and cause something very similar.

When it "clanks", is it just ONE clank, 2 or 3, several dozen, what? Does it repeat, if so, a fraction of a second interval, 1-2, 5-6, describe.
I’ll try to record the sound.
Smooth pavement or off road, though not as much on smooth level pavement. Seems load related, more than smoothness of the surface.
I have t been able to get the noise pedaling with the motor off.
Doesn’t occur as much going downhill. Doesn’t occur at all coasting.
It still happens at lower assist, but isn’t as loud or as frequent
It’s intermittent with no cadence. Sometimes once every 10’ sometimes every 20-30’. Once every couple seconds on average.
I’ve checked the motor mounts numerous times. It’s very solid, I can’t move it.
But I’ll check again.
Have checked all the bolts and everything seems tight.
I’ve replaced the chain, front sprocket, rear wheel, (to convert from freewheel to cassette). The entire drive train..
 
Just a wild guess, but you might check the tension on all your rear spokes. I was having an similar noise on my rear tire and I eventually found some loose spokes.
I checked the spokes. I also replaced the entire rear wheel, thinking it might be the old style clunky freewheel system. The cassette wheel makes the same sound. I also took the freewheel apart and put heavier grease in the pawls. No change.
 
Well, what is left at the rear end of the bike? Fenders or rack? Screw stuck in the tire, in between deep treads where it does not always make contact? Taillight?

Are you CERTAIN the noise is at the rear?

Can you get the same SPEED while pedaling? How about downhill with the motor OFF? Has the noise EVER occurred with motor off, and has it occurred with motor ON at a speed and road condiion that you can duplicate with the motor OFF.

It is irregular, so not rotational. Almost everything at the rear of the bike has been replaced.

Is this anychance a recumbant, with your head way behind where it would normally be? So that a motor noise might seem to be in the rear instead of the crank?

Can you closely examine the drive gears in the motor? I'm thinking a worn tooth, which occassionally allows some chain slap, which would tend to happen more under load, while still being irregular.

Really reaching, but all the easy ones are pretty much eliminated.

Where ANY of the original parts re-used when replace rear wheel and chain? Master link, chain tensioner?

Can you connect anything you do to make the noise stop, or start? Try shutting motor off, or use ebrake lever.

Kickstand?

You say the pattern varies, but when it DOES happen, is it consistent through that one event? Roughly how long do these events last?

Gonna guess maybe each time you get off the throttle a bit, or a lot, and then it stops?
 
Assuming that you have done all the basics that you have listed; it comes down to the bike frame itself; a rear drop out only secured to a stay, for instance
 
Assuming that you have done all the basics that you have listed; it comes down to the bike frame itself; a rear drop out only secured to a stay, for instance
I looked at that. Seems solid. I used a solid axle on the first wheel and quick release on the new one. The frame is of course chinese, but is new and wad straight and we’ll made. I bought it for this project. I rode the bike before doing the conversion with no issues.
 
Based on your recent descriptions, we can rule out the pawl thing I was talking about. If the noise is occurring repeatedly then, if you are under constant power as it recurs, it can't be pawl engagement. And it sounds as if you have changed every component in the drivetrain.

So if it is not the drivetrain components, then it may be something acting upon them. Like a kaka chain alignment causing the chain to worry the cogs a little. But usually that sound is a light click or even a short chain skip.

Is the sound coming from the wheel, or the motor (in the back or just below you)? A sound recording would not be the worst idea in the world.
 
Based on your recent descriptions, we can rule out the pawl thing I was talking about. If the noise is occurring repeatedly then, if you are under constant power as it recurs, it can't be pawl engagement. And it sounds as if you have changed every component in the drivetrain.

So if it is not the drivetrain components, then it may be something acting upon them. Like a kaka chain alignment causing the chain to worry the cogs a little. But usually that sound is a light click or even a short chain skip.

Is the sound coming from the wheel, or the motor (in the back or just below you)? A sound recording would not be the worst idea in the world.
It seems to be coming from the wheel hub area. And chain alignment was my first thought, but it does it even in the mid gears where the alignment is very straight.
I’ve about given up and decided to live with it. The bike rides great and other than that clunk now and then, it’s fine. But it does interfere with the primary use in the woods of sneaking around my hunting lease looking for pigs. .
Still way quieter than my 4 wheeler..
There’s an ebike shop about 50 miles from me. Might take it down there for another opinion. Guess I could always convert it to a hub motor.. nah..
Thanks for your input. If I get it diagnosed, I’ll update the thread.
Greg 2F635E50-DCE9-4772-BF71-00B4AAF9AA8A.jpeg
 
Well, what is left at the rear end of the bike? Fenders or rack? Screw stuck in the tire, in between deep treads where it does not always make contact? Taillight?

Are you CERTAIN the noise is at the rear?

Can you get the same SPEED while pedaling? How about downhill with the motor OFF? Has the noise EVER occurred with motor off, and has it occurred with motor ON at a speed and road condiion that you can duplicate with the motor OFF.

It is irregular, so not rotational. Almost everything at the rear of the bike has been replaced.

Is this anychance a recumbant, with your head way behind where it would normally be? So that a motor noise might seem to be in the rear instead of the crank?

Can you closely examine the drive gears in the motor? I'm thinking a worn tooth, which occassionally allows some chain slap, which would tend to happen more under load, while still being irregular.

Really reaching, but all the easy ones are pretty much eliminated.

Where ANY of the original parts re-used when replace rear wheel and chain? Master link, chain tensioner?

Can you connect anything you do to make the noise stop, or start? Try shutting motor off, or use ebrake lever.

Kickstand?

You say the pattern varies, but when it DOES happen, is it consistent through that one event? Roughly how long do these events last?

Gonna guess maybe each time you get off the throttle a bit, or a lot, and then it stops?
Pretty certain it’s in the rear hub area.
The clunk is not constant at all. might go 50 yards without it, then clunk in 5 or 20 feet. And then go 50 or 5 without a sound. This is a new everything unit. New bike, new conversion. Maybe 30 miles on it. Upright bike, see pic.
I suspected drive train, and replaced everything in it. Drive sprocket, chain, derailer, rear wheel and cassette. No change. Tried reprogramming with the Egg Rider, and getting the assist down to almost nothing takes the noise away, but defeats the purpose of the ebike.
When I turn the motor off and pedal or when coasting downhill, it goes away.
I was wondering if it’s some kind of chain interference, but there’s no jerkiness when it makes the clunk.
The sound is like when you jerk the cranks back and forth against the pawls.
Lifting the rear wheel and running it with the throttle and no resistance, it’s quiet and smooth.
It does it whether pedaling with assist or throttling. No pattern at all.
I was thinking the motor might be pulsing, but I should feel that?
 
If its coming from the rear wheel (not the motor) and you have changed wheels entirely, and one is a freewheel and the other a cassette ()there's no point in pulling off the cassette body and greasing its internals because we've established it is on both wheels) then whats left back there? Not the chain since you replaced it.

There's only one thing left. The derailleur. I looked at your pic, where you are on your big cog, and congratulations... you look to be one of the few who knows how to do proper chain length on a long cage 1x drivetrain.

Looking a little deeper at this, you said the chain is 7-speed. 7s is not uncommon for a freewheel, but it sure is for a cassette. What is your chain, derailleur and shifter? What does derailleur cage alignment look like vs. the cluster? Is it parallel as it should be?

I'm thinking this has nothing to do with the motor. Since it happens with both freewheel and cassette, that crosses out a lot of possibilities. But not catching on a tooth either on the pulley or the cluster might be the culprit. Under power there's no slack in the chain and the lines have to be spot on.
 
If its coming from the rear wheel (not the motor) and you have changed wheels entirely, and one is a freewheel and the other a cassette ()there's no point in pulling off the cassette body and greasing its internals because we've established it is on both wheels) then whats left back there? Not the chain since you replaced it.

There's only one thing left. The derailleur. I looked at your pic, where you are on your big cog, and congratulations... you look to be one of the few who knows how to do proper chain length on a long cage 1x drivetrain.

Looking a little deeper at this, you said the chain is 7-speed. 7s is not uncommon for a freewheel, but it sure is for a cassette. What is your chain, derailleur and shifter? What does derailleur cage alignment look like vs. the cluster? Is it parallel as it should be?

I'm thinking this has nothing to do with the motor. Since it happens with both freewheel and cassette, that crosses out a lot of possibilities. But not catching on a tooth either on the pulley or the cluster might be the culprit. Under power there's no slack in the chain and the lines have to be spot on.
I was thinking it might be a little chain engagement problem. It’s a Zonkie 1/2x3/32 chain and a shimano Alivio cassette. Shimano derailleur, but don’t recall the model off hand. It’s a new one and adjusts correctly, shifts smoothly, as far as I can tell. Have a 32 tooth aftermkt front drive aluminum sprocket, but it does the same with the bafang 44t steel one too.
I’m wondering if a high end chain might help? Are there some that operate more smoothly? Even changed the shifter.
Maybe one of those dished sprockets for a little better alignment?
 
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