Stock GNG 450W - Chain or Belt? and Noise Level

[Dman12]

Hello,

I am interested in getting a kit from GNG, since the price is right and I have less chance of problems with the custom when I order from china,

I am going to run it on stock everything, with 48v battery, 1000w of power is enough for what I need,
the biggest hill around is probably 10% grade, rest of the city is flat with some 4-5% grades at best.

I want the chain reduction because it is more durable, but the noise concern me, how is the noise level compared to a brushed UNITE geared motor? I have the my1016z2 250w motor and I can deal with the noise, but I don't want another noisy bike,
Then I think about the belt version but I am afraid I'll have to replace the belt every 2 weeks.

Please give me your advice,

Thank you.

 

[Whitehawk]

I have the new GNG 650w and yes the chain reduction is.. VRRRRRRRRRRR very noisy and that's not fine :/

I will upgrade to #25 chain and sprocket this week, I'm waiting to receive them, I think after that the noise level will be acceptable

 

[Dman12]

From what I've read its the tensioners that make most of the noise,

I think I am going with the belt version, and few spare belts, if I could find a place that sells them.

 

[Whitehawk]

No, the tensioner don't really make noise, the noise come from the first chain reduction, the sprocket (11 tooth) is too small for the original big chain.

I think I will receive tomorrow the #25 reduction so I could show to you the difference and say if the noise level is better after this mod.

 

[skyungjae]

The chain drive kit I have didn't even have a tensioner on the primary side. If you want stealth, then belt is the way to go.

If you plan on doing any trail riding you should start pricing up potential upgrade parts. The 150mm spindle on the factory bottom bracket bends easily during off road use.

 

[Dman12]

No, the tensioner don't really make noise, the noise come from the first chain reduction, the sprocket (11 tooth) is too small for the original big chain.

I think I will receive tomorrow the #25 reduction so I could show to you the difference and say if the noise level is better after this mod.

Waiting to see the results.
will you make a comparison video?

The chain drive kit I have didn't even have a tensioner on the primary side. If you want stealth, then belt is the way to go.

If you plan on doing any trail riding you should start pricing up potential upgrade parts. The 150mm spindle on the factory bottom bracket bends easily during off road use.

Yea I am looking for stealth mode :lol: for noise I have my geared motor - with it straight cut reduction gears there's enough noise to let people know I'm coming from a mile away

So for now I'm leaning towards the belt version, mainly because I can always make a chain mod (take some work but I saw here it is possible).
also found a place to get replacement belts for cheap (460-5m-15) , so I think its a good solution for running on stock as a commuter, until I'll have the time and money for upgrades to #25 chain, as well as other things like the freewheels and the BB.

 

[r3volved]

The stock belts are 475-5m-15

 

[Samd]

It would be useful to measure the noise in decibels using and Android or iPhone noise level app.

Also a bit high end but you could record the sound as an audio file and throw it into Audacity software and do a fourier transform, look at the main frequencies before and after. Shift them outside the human hearing range.

 

[Dman12]

It would be useful to measure the noise in decibels using and Android or iPhone noise level app.

Also a bit high end but you could record the sound as an audio file and throw it into Audacity software and do a fourier transform, look at the main frequencies before and after. Shift them outside the human hearing range.

doesnt the phones mic quality affect the readings?
I think if you want to do it you will have to use the same device to record as well

but I will try to take a measurement for my brushed motor.

 

[Dman12]

I tested my motor noise with "Sound meter" app on my android and got about 85db - 50cm away from the motor at full speed, starting from 60db with motor turned off.
here is a recording, again, from 50cm away at the crank level.

https://soundcloud.com/guy-da/my1016z2-motor-noise-246v

if anyone could try to compare it to the GNG it will be very helpful.

 

[skyungjae]

One thing to note is that the noise level is different if the bike is under load. :wink:

 

[Gab]

I tested my motor noise with "Sound meter" app on my android and got about 85db - 50cm away from the motor at full speed, starting from 60db with motor turned off.
here is a recording, again, from 50cm away at the crank level.

That's pretty Loud 85DB ! From the net:
80 decibels sounds like a Garbage disposal, dishwasher, average factory, freight train
90 decibels sounds like a Busy urban street, diesel truck, food blender

Has anyone measure the GNG in the same way ? As Skugange mentioned the noise will change under load or not. The best way you can do that is with the rear wheel off the ground, then do full power and then vary the brakes from 0 to 100% for full load, then you can see the peak Dba at ALL RPM and all loads.

 

[r3volved]

If you really want legit numbers then you'll need to dyno it within an anechoic chamber.
I may be able to get access to our chamber downstairs...any suggestions on building a cheap dyno or roller to add load?