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[JediLeba]

So I just bought a 2015 SR from a guy, and the thing makes what I consider a LOT of noise. It’s a heavy whirring sound under power, or even if I have it turned on and manually maneuvering into position.

It has 11k miles, mostly highway as I understand it. He was driving to work and home most days at 70mph, round trip 125 miles. So it has some wear - but should the engine noise be so noticeable on a 3 year old bike?

[BrianTRice@gmail.com]

Welcome!

First, know that Zero’s do make some sounds, and it’s hard to tell over the internet whether you’re hearing a normal or abnormal sound, but this sounds like the normal “whirring” that the motor sometimes makes, BUT it might not be.

There is a wiki that acts like an unofficial manual for us, that I mostly maintain.

I have a “directory” of sound pages that might help you diagnose what you’re hearing:
https://zeromanual.com/wiki/Category:Sound

Here are the normal motor sounds one might expect:
https://zeromanual.com/wiki/White_Noise
https://zeromanual.com/wiki/Motor_Whine

[caza]

I also recently got a used 2015 SR and it makes some sound, but it's pretty familiar whirring of the motor and whining of the controller.

My zero makes a little bit of noise just keyed on as well, but the previous owner showed me that he replaced the headlight with an LED which has a cooling fan.

[BrianTRice@gmail.com]

Now here’s what MIGHT be wrong if the motor makes a more unpleasant sound:
- Bearing wear
- Motor encoder or controller alignment issues (can arise if no dealer maintenance is performed).
- Belt mis-alignment (can break a belt early)

I would take your bike to a dealer for diagnosis if you can’t readily identify it as one of the normal symptoms listed in my first reply. Any of these conditions are important to fix (possibly not urgent, but definitely important).

[BrianTRice@gmail.com]

I also recently got a used 2015 SR and it makes some sound, but it’s pretty familiar whirring of the motor and whining of the controller.

My zero makes a little bit of noise just keyed on as well, but the previous owner showed me that he replaced the headlight with an LED which has a cooling fan.

It’s not the controller that whines, but the motor shaft bearings.

LED headlamp fan noise is a condition worth mentioning for used bikes, thanks.

[BrianTRice@gmail.com]

I’ve separated this page from the White Noise page for clarity:
https://zeromanual.com/wiki/Motor_Whirring

[JediLeba]

Thanks for the replies! I test rode a 2018, it didn’t sound anything like this noise. It was actually pretty silent. Thanks to your replies, I have better descriptive words for it, too. Now I would not say this is a whirring, but more a growl, maybe of the bearings. It isn’t until the bike moves that the sound starts, and naturally louder as I move faster. If the bike is switched off and I’m maneuvering it into place, I don’t get that sound.

Do those pages have sound files to listen to? I didn’t see any.

I do want to take it to a dealer (though I’m afraid of the diagnosis) they just aren’t super close to me and I need to plan that trip.

[Richard230]

Thanks for the replies! I test rode a 2018, it didn’t sound anything like this noise. It was actually pretty silent. Thanks to your replies, I have better descriptive words for it, too. Now I would not say this is a whirring, but more a growl, maybe of the bearings. It isn’t until the bike moves that the sound starts, and naturally louder as I move faster. If the bike is switched off and I’m maneuvering it into place, I don’t get that sound.

Do those pages have sound files to listen to? I didn’t see any.

I do want to take it to a dealer (though I’m afraid of the diagnosis) they just aren’t super close to me and I need to plan that trip.

My 2018 S when it was new made a growling noise that my 2014 S did not make. It appeared to be coming from the wider drive belt, which was set up by the factory near the upper limit of the belt tension specifications. As I rode the bike the noise slowly was reduced as the belt broke-in and now I no longer hear the sound. The sound completely disappeared by about 600 miles.

[DonTom]

I also recently got a used 2015 SR and it makes some sound, but it's pretty familiar whirring of the motor and whining of the controller.

My zero makes a little bit of noise just keyed on as well, but the previous owner showed me that he replaced the headlight with an LED which has a cooling fan.

I have an LED headlight in both of my Zero's-- but the one with the heat sinks--no fan.

I find the Zeros kinda make the same sound as a BART train, just not as loud. I like the sound the Zero's make.

-Don-  Reno, NV

[BrianTRice@gmail.com]

Thanks for the replies! I test rode a 2018, it didn’t sound anything like this noise. It was actually pretty silent. Thanks to your replies, I have better descriptive words for it, too. Now I would not say this is a whirring, but more a growl, maybe of the bearings. It isn’t until the bike moves that the sound starts, and naturally louder as I move faster. If the bike is switched off and I’m maneuvering it into place, I don’t get that sound.

Wait - so, it makes this sound when the motor is pushing the vehicle even at slow speed, but not when you manually push the vehicle at the same speed?
- If so, that is definitely an encoder issue, and you'll need a dealer to perform a controller alignment procedure.
  https://zeromanual.com/wiki/Unofficial_Service_Manual#Controller
- The motor controller has to apply a 3-phase field to the motor to apply torque correctly to the rotor. Alignment checks all of this.
- If your controller isn't aligned, that's bad and could ruin the bearings and the motor over time or you might wind up with a more urgent problem.

The Sevcon tooling for this is sort of available separately but won't work "out of the box" on 2016+ Zeros (IPM motor models); the dealership software is required which we don't have as a community.

Do those pages have sound files to listen to? I didn’t see any.

That's a good idea, but someone hasn't sat down and done it. One does have a Youtube video with the sound, at least.

It'd be a small project, I guess. If someone hands me labeled audio files (email my user name at gmail dot com or upload to the wiki), I can integrate it. If you take good Youtube videos, I can integrate those, too.

[BrianTRice@gmail.com]

Controller alignment is like checking valve clearances on a combustion engine - it’s a preventative maintenance task worth doing once a year or so that normally is trivial, but if no one checks and the alignment drifts, eventually you have a serious problem.


It's nice that a dealer can do it quickly without much teardown - it's fixable with a laptop connected to the controller, but there's no way for an owner to perform the same procedure yet, at least on newer bikes.

[DonTom]

Controller alignment is like checking valve clearances on a combustion engine - it’s a preventative maintenance task worth doing once a year or so that normally is trivial, but if no one checks and the alignment drifts, eventually you have a serious problem.


It's nice that a dealer can do it quickly without much teardown - it's fixable with a laptop connected to the controller, but there's no way for an owner to perform the same procedure yet, at least on newer bikes.

Is that the same as adjusting the commissioning? What is it really doing?

BTW, can you explain what type of signal actually goes to the motor?  I mean is it something like a type of PWM or what?

I really don't know anything about these motors used in EVs, but I have been in electronics all my life. But  I am quite new to EVs and motors of any type.


-Don-  Reno, NV

[JediLeba]

Sorry, I must not have been clear. With the key turned on, the bike makes noise when it is in motion, whether I am using the throttle or maneuvering with my feet. When the bike is sitting still, it is silent, whether the key is on or off.

With the key turned off, and I am maneuvering with my feet, the bike is still silent.

Hope that clarifies the issue. Thanks again for all the input. I’m trying to learn all I can about it.

[BamBam]

Is this the noise you are referring to?  See link below and click on the video clip to hear it.  If so, it is completely normal.  The "whir" noise is most evident when moving the bike (either forward or backward) with the key on and no throttle applied.  The noise may still be present with the throttle applied (not sure about this), but it's definitely not as pronounced.  Maybe because the whir noise is overtaken by other noises such as motor, wind, tires, etc.

https://zeromanual.com/wiki/Motor_Whirring

[BrianTRice@gmail.com]

Is that the same as adjusting the commissioning? What is it really doing?

BTW, can you explain what type of signal actually goes to the motor?  I mean is it something like a type of PWM or what?

“Commissioning” is when you set something up for the first time. Zero overuses this jargon and confuses “alignment” with commissioning in the owners manual.

They are the same process, but alignment is the calibration performed once by the commissioning process and then repeated later as a recalibration.

The controller is a switching power supply that sends current to 3 cables in phased sine waves. The switching attempts to produce a smooth sine wave.

The phasing is what has to be aligned. Each of the 3 inputs drives different coils physically that pull on the rotor. The forces need to balance out, not leading to a net lateral force on the rotor and shaft. It also shouldn’t precess or wobble or slip.

The process of making the sine waves is “encoding”.

The motor has sensors for encoder alignment to tell the exact angle of rotation of the rotor. If those sensors are inaccurate, encoding can be rough or fail entirely. The sensors are embedded within the motor so for owners they just compensate in the controller for the drift, or swap the motor if the signal is bad enough that the controller can’t work with it.