Rear hub motor noise. Truckrun.

[griffinator]

Hello, I'm pretty new to the ebike world but have been a mechanic my whole life. I have a new victrip titan 1month old. The motor has started making a grinding noise when I get to faster speeds and under loads. (Flipped it over and ran with no noise).thought it was bearings but seems unlikely . After reading another of posts I'm starting to think it may be a wiring problem. When riding a few weeks ago, throttle quit responding and had to jiggle wires up by controller to get working. Is it possible that my controller wires would cause grinding sound? Attached some pics and video I took for warranty claim which has been denied because you can't really hear noise in video.

 

[amberwolf]

What specifically happened just before the initial problem? What specifically fixed it?

What specifically happened just before this one?

Knowing those might help determine the problem.


Regarding noises, the three most common are that gears in geared hubmotors can be damaged by impacts, overheating, overtorque, etc., and the hall signals in sensored systems can fail for several reasons (wiring faults, overheating, water damage, etc), which can cause a motor to run rough from not being driven correctly, and a phase wire connection between motor and controller can be faulty, high resistance, so the motor will run rough as it's not being driven fully.

There could be other reasons, such as corrosion from water damage in either motor or controller or connections, etcs.

So knowing what happened could narrow down the possibilities.

 

[griffinator]

The bike is basically brand new. Only had it for a month and it has never been wet. Also I had started checking the motor for excessive heat once the noise started and it was cool. I'm interested in knowing what would cause overtorque? I have ridden it for long distance, about 60 miles one day but it's rated for up to 90 with pedal assist. Never excessive weight. One night I was riding and had stopped for just a few minutes and then tried to go and had no throttle response at all. Started looking at wire connections and gently pulled wires to make sure nothing had come loose. Tried again and throttle worked for about 10 feet and quit. So just pushed the wires on my throttle and bike worked.Never had an issue again. About a week later started hearing noise like combo of grinding and rattling which has gotten progressively worse and louder. Motor seems to have full power still, easily hits 28 to 30 miles hour and still has plenty of take off power from stop. Took it to local shop and mechanic also said could be hall sensor and that meant replacing motor. I've been reluctant to open motor just because I'm trying to submit warranty claim but they are denying claim anyway so.. If I open it can I test the sensor?

 

[amberwolf]

Progressive failure is not normally a sensor fault. That usually either is a problem or it is not. Progressive failure is usually a mechanical issue (like gears in a geared hub). Also, hall sensor failure usually causes problems at startup from a stop under load (even if it doesn't during no-load offground testing).

No need to open it to test sensors, you can use the info at ebikes.ca learn troubleshooting hall sensors, or in other hall sensor test threads to verify them.

If you can't leave them connected to the controller with the controller powered on while testing (simplest way, but hard to do on today's common waterproof plugs), you'll need to supply 5v to them (like from an old USB charger you're not using), and have a small resistor (1kohm to 10kohm, can be found in a fair bit of old junk electronics) to connect to the signal wire of the sensor under test and the 5v source to provide a "pullup", since the halls don't output anything, they only ground an existing 5v pullup from the controller on each signal line, or unground that signal, everytime a magnet of the opposite polarity passes them (vs the previous magnet). (so "on" is about 0v, and "off" is about 5v). You'll need a voltmeter, or an LED (also salvagable out of the old electronics, for instance).

If you can post which specific motor you have, and a picture of the disconnected motor-to-controller plugs that shows the pins, we can try to find out if the pin diagram (pinout) for that connector is already known.

There are also "ebike testers" that can be used to verify motor/controller general operation, this is one randomly chosen example from a google search

Amazon.com

but they don't usually come with modern connectors on them, so to make it "easy" you have to also get extension cables or "pigtails" to match the connnectors on things you need to test, and then wire them up in place of the connectors the tester comes with. That's a potentially costly PITA if you only need to do one test on one bike one time.


If pushing the wires on the throttle fixed the problem, it means that there is a broken wire in that cable, and pushing on it reconnected it, but it will not stay that way--eventually it will come loose again. If you pushed it on the throttle side of the throttle-controller connector to make it work, then it's probably broken on the throttle cable, and the throttle would be the part to replace (or repair the cable of). If on the controller side, then the controller.

 

[griffinator]

Up

Progressive failure is not normally a sensor fault. That usually either is a problem or it is not. Progressive failure is usually a mechanical issue (like gears in a geared hub). Also, hall sensor failure usually causes problems at startup from a stop under load (even if it doesn't during no-load offground testing).

No need to open it to test sensors, you can use the info at ebikes.ca learn troubleshooting hall sensors, or in other hall sensor test threads to verify them.

If you can't leave them connected to the controller with the controller powered on while testing (simplest way, but hard to do on today's common waterproof plugs), you'll need to supply 5v to them (like from an old USB charger you're not using), and have a small resistor (1kohm to 10kohm, can be found in a fair bit of old junk electronics) to connect to the signal wire of the sensor under test and the 5v source to provide a "pullup", since the halls don't output anything, they only ground an existing 5v pullup from the controller on each signal line, or unground that signal, everytime a magnet of the opposite polarity passes them (vs the previous magnet). (so "on" is about 0v, and "off" is about 5v). You'll need a voltmeter, or an LED (also salvagable out of the old electronics, for instance).

If you can post which specific motor you have, and a picture of the disconnected motor-to-controller plugs that shows the pins, we can try to find out if the pin diagram (pinout) for that connector is already known.

There are also "ebike testers" that can be used to verify motor/controller general operation, this is one randomly chosen example from a google search

Amazon.com

but they don't usually come with modern connectors on them, so to make it "easy" you have to also get extension cables or "pigtails" to match the connnectors on things you need to test, and then wire them up in place of the connectors the tester comes with. That's a potentially costly PITA if you only need to do one test on one bike one time.


If pushing the wires on the throttle fixed the problem, it means that there is a broken wire in that cable, and pushing on it reconnected it, but it will not stay that way--eventually it will come loose again. If you pushed it on the throttle side of the throttle-controller connector to make it work, then it's probably broken on the throttle cable, and the throttle would be the part to replace (or repair the cable of). If on the controller side, then the controller.

Update. Ordered tester from link and waiting for that.was trying to get a clear audio recording of noise but wind overloads mic so I put PAS on one so I could get noise at lower speed and nothing, no noise. So I tried all PAS settings 1 through 5 and found motor only makes noise on PAS 5. Does this help diagnosis?

 

[amberwolf]

What speed is the motor wheel at when the noise starts?

Does it reach taht speed (without noise) at other PAS levels? If so, it's not *just* speed, it's also whatever else is different between those specific levels and the one it makes the noise at.

 

[griffinator]

What speed is the motor wheel at when the noise starts?

Does it reach taht speed (without noise) at other PAS levels? If so, it's not *just* speed, it's also whatever else is different between those specific levels and the one it makes the noise at.

Ilnoise only happens on PAS 5 and starts at about 20 mph. As long as I'm on throttle
it sounds like marbles in hub, kind grinding . But it stops when I let off throttle and coast. And, the other day going downhill I hit 38mph just coasting and no noise. So it's only on PAS5 at 20mph and above while on throttle! Could it be a fault in my display where I adjust PAS?or possibly in throttle?

 

[amberwolf]

No, couldn't be in those.

It's almost certainly mechanical in the hub itself. The gears is the most likely thing. They're only driven when using the motor. If you pedal in the same conditions (vs throttle) does it do the same thing, assumign you have a PAS sensor?

The clutch is unlikely to make noise since it's not slipping, and would probably be doing that at high torque loads not high speeds. It also isn't likely that the clutch is grabbing when it shouldn,t since the noise stops without the motor running.

Does the noise start suddenly, where it doesn't happen at all up to a certain point and hten suddenly its' just there at full loudness? Or does it gradually get louder from a point you can't hear it until it's at it's loudest?

 

[griffinator]

Yes, noise is also there when I pedal. Also, it kicks in at a certain speed, around 20mph and definitely gets louder as speed increases. It's looking like truckrun is not going to budge on warranty claims and so I figure I've got nothing to lose by opening and inspecting it. Would you recommend that at this point? I guess what seems strange to me is that most mechanical issues I would think, would be noticeable no matter what my PAS was set at. On PAS4 I still hit over 20mph with no noise but again I defer to your opinion do to my limited experience with this motor technology. After reading a great deal of posts about this issue, I'm wondering if it could be a magnet has separated Inside?

 

[griffinator]

I was mistaken on earlier info. It does make the noise in lower PAS settings also. So I think at this point I just need to get into hub and look. Also have hall tester coming in today. Try to give you more info once I do these.

 

[amberwolf]

If a magnet had separated in any outrunner (like hubmotors almost always are), you would have noises at high currents, rather than high speeds. It would almost certainly be worse at lowest speeds as the currents are highest then with no BEMF to counter them, since the stator current would be physically dragging the magnet around...at speed the centrifugal forces would help to push and hold the magnets into place a bit (not much), and currents would be much lower, stator magnetic forces lower, etc.

If you reach the same speed (under motor power only) that the noise occurs at in a different assist level but there is no (or much less) noise, then whatever the difference in how those modes operate is directly related to the cause of the noise (not necessarily is the cause, but directly affects whatever does cause it).

 

[griffinator]

Update, and wanted to say thanks for feedback. Truckrun has finally agreed to replace motor after about 20 videos I sent with noise although they still say motor sounds normal. Whatever.!!! So new motor on the way and I will then take apart this one and let you know what I find that may help someone in future. Also, motor completely stopped working other day on road. Had no power but made terrible grinding noise and I picked up rear wheel gave it throttle and it spun really slow sounded terrible. I let sit, pulled battery out and put back in and bike took off with full power and same old noise at 20mph
So, coincidence or power issue??? We'll see when I get new motor if it does same thing then I know it's power/control issue. Crappy way to diagnose I know but I got new tester and only way to connect is to cut into factory wiring ( all shielded cables).to be cont.