Geared motor noise

[Jost]

Looking for opinions - I have a bafang 750 w geared motor (48v) on my fatty and am impressed with how quiet it is. It's my commuter but also my trail road cruiser. In trail road cruise mode, I'm going slow and listening to the goings on in the woods.

My upcoming project is to put a nice system on my Cruzbike Quest. This is not a speed bike but an all around cruiser with a modest laid back seat back. Being a front wheel drive recumbent, it appears to be easy to drop a front drive system on the rear (100mm dropout spacing). I'm looking strong at the Ezee v2 package from the Grin folks. The motor simulator indicates it will do well for acceleration and more than adequate for the speeds I'll run (+-25mph) once out of town and cruisng. I don't know anyone with one of these motors (or anyone in e biking for that matter.....) and am wondering what the gear noise level on this motor would be compared to the bafang.

My thinking is:

1) on the quest, I'll generally be going fast enough, that most of the time, the wind noise is more of a factor.

2) however, my ears will be closer to the motor than on my upright fatty

3) I get the impression from my forum readings that the ezee is a higher quality motor so may no be as noisy to start with


I understand that DD motors are quieter but my riding will be 50% stop and go with 50% cruising at speed. I will have some long modest grade hills involved as well, so leaning to the geared setup.

Thanks for your experienced opinions.

Jim

 

[motomech]

I have a V1 on the rear of my 2WD mountain bike;

View attachment 1

I'm still using the original, grey, soft nylon gears.



With 46 Volts of LiPoy and a 25 Amp elifebike controller it is dead silent. I don't hear anything except the block-tread tire.
The only other motor/controller combo I have run that was as quiet was the very sm. Q100CST/SO6S sine wave.

I have found that the controller has something to do w/ system noise output. Not only the Current run thru the system but the wave profiles The elifebike square wave is a soft hitting controller which in many ways emulates a sine wave.
I have used a Lyen(Infineon) 25 Amp Mini Monster, a hard-hitting controller and the system was audible accelerating. It also had noticably higher performance. Still, not what I would call noisy.
The Ezee has 16 pole magnets and I expect the V2, even w/ it's wider stator, is a very quiet motor relative to to other geared motors

 

[Jost]

Moto,

Thanks for your comments.

I also need to check on the motor fit with the disc brake caliper. I have the dimensions of the motor so will do some measuring tonight.

From what I can tell in your picture, those gears look to be in good shape, how many miles on that motor?

My assumption is that since I'm not going to be bouncing around on rough terrain, there should be no issue with the gears.

Jim

 

[motomech]

There is a history w/ the Ezee V1 and Grin.
Despite the high quality of the motor(very neat windings among other things), there was a production defect that effected many motors. The hall wires were too short and were stretched tight to the PCB and the result were cold-solder joints. I believe this was in '07.
I bought a pr. during a Xmass clearance sale in '10, they were advertized by Grin as "working", but in fact, both were defective.
Not aware of what the actual cause of the problem was, I parked them and only after reading here of others and how they fixed them, that I repaired one. That required lengthening the Hall wires and installing a new PBC and sensors.

You seem concerned about the service life of the Ezee, probably needlessly. All the geared motors have been around for a while and their limits are well known, exceed those limits and expect Sprag clutch breakage and melted gears. Stay at reasonable power levels and they will be trouble free for many 1,000's of miles.
I am getting close to the "limit" on this V1 @1100 Watts. On hard starts, I feel something I interpret as "gear flex". I have a set of the stronger blue composite gears that I could install one, or all. Then the clutch would be at risk and frankly, since I am not doing much off-road riding these days, I don't feel the need.
So what could the V2 handle is the question, especially since it has a higher power handling capacity?
That is a little hard to say since there is some confusion regarding gears and clutchs for this group of larger geared motors.
I wrote this about a year ago;

All Puma's, BMC's, Mac's and Ezee's(CST excepted, it's too new to know), use 4 versions of basicly the same clutch/gear ASM.

As far as to what is avail. today, Ebike CA offers the V1/V2 clutch, but is out of stock;

EM3ev offers what is described a "MAC only" clutch and implies it's the "one piece" V3 clutch, but it is NOT. It is the V1/V2 two piece clutch that fits any of the above listed motors. It is my understanding that the V3 clutch has had some problems(fracturing?)and Paul has pulled it from the line-up(He needs to up-date his web site info.).
Ebike SF offers the V4 clutch;
http://www.ebikessf.com/BMC-V4-Clutch-Assembly
All new clutch/gear ASM's come w/ the blue composite gears.

So we know the V2 has the slightly stronger V2 clutch, obviously. As to what gears are used, I'm not sure if they are the grays or the blues. You could ask Grin.
But it's probably safe to say the V2 should share the cautions of the MAC, that is limits around 1200 to 1300 Watts(Paul has changed his recommendations, to very conservative values). Riders that need more should consider Paul's "Upgraded" MAC.
So what does the Ezee's quality mean in terms of service life? Will it last longer than the "crude" BPM?
Probably not, the BPM is good enough.
But there is one thing(2 actually)that the Ezee and BMC has and the BPM doesn't(not sure about the MAC)and that is real dedicated seals located to the outside of the brg.s. A big plus in wet conditions.
But then, using hub motors in wet conditions is an area of controversy best left to another time..

 

[dogman dan]

If quiet is what you want, go DD. But like you said, at 25 mph you will have wind noise. Eventually, a geared motor generally gets louder, and you will hear it through the wind at 25 mph. I've never been bothered much by the noise at 20 though, or less, even on hard run, more noisy, older motors.

In general, a re grease tames a noisy one at least for a time.

Also bear in mind,, motors I have are usually in hard use testing for E bike kit. I'm trying to break it hard as I can, so I might overheat a motor and sling off the grease faster than some.

 

[Jost]

Appreciate the replies. The seal comments are reassuring as we have a rainy season around here (north end of sub tropical).

Being a recumbent, I'll rarely use 100% power and that level will be well within the spec'ed power limits. I'm looking forward to the CA that comes in the kit to set parameters. On a recumbent cruiser, I'm thinking this system is going to have a life of leisure so things will last. Retirement is coming, things lasting is a good thing ........ :|

Did some measurements last night and it looks like there won't be a conflict with the motor and the brake caliper. Will check again this weekend to confirm. Won't be moving on the kit for a couple of months but fired up.

My next consideration will be how to mount the batt. Somewhat unusual frame on this bike.

Thanks again!

Jim

 

[Jost]

A little slow this morning so able to hit google and then search the forum for info on the planetary gear material. I've found beaucoup references to the fact that different material is available (looking at plastic gears) but nothing specific.

Would anyone have a link to further my "edumacation"?

Did find interesting reading on # of poles, thickness of laminations and the two speed geared hubs etc. A lot to learn.......

Thanks,

Jim

 

[motomech]

I already answered that.
Over the years, different materials have been tried on geared motors, but it always comes down to Nylon and steel. I have never tried steel, but the reviews I have read, installing them(all 3), produces a motor that sounds like a dentist's drill. Personaly, I think some "give" of the Nylon material is a good thing.
At least three different "hardnesses" of Nylon have been tried in the larger geared motors, but now, the "blue" gears, often call "composite" gears, have become the defacto replacements for the O.E.M. white or gray gears;

http://www.ebikes.ca/shop/electric-bicycle-parts/motor-parts/ezeegear.html

Furthering your education never hurts, but in the "real World", I very much doubt you would ever have a problem w/ the gears. I weigh 250 Lb.s and have been riding geared motors, from minis to the Ezee for years and have never had a prob. w/ them. And that includes lite off-roading.

 

[Jost]

motomech,

Thanks for the response. I re-read your previous post: you do mention a composite blue gear vs a grey gear. I've seen pictures of white gears. So the grey and white are nylon gears and the same?

The blue gear is a stronger composite - nylon composite with other material? What material?

In reality, these gears should last as I'm not going to be pushing them but still interested in knowing more about them "just because". I saw a fellow on yt that had a trike/wheelchair like machine. He had taken the geared motor apart as he thought the gears had a problem (turned out to be the clutch mechanism). IIRC, he put a new blue gear assembly back in but replaced one gear with a metal. Was interesting though more than I'd want to tackle/need.

I appreciate your patience with a newbie. Since I don't know yet what I don't know, I may be going after stuff that's not really a "problem" but it's all very interesting to me.

Thanks again,

Jim

 

[Jost]

I checked the link to the grin site that shows the blue geared replacement assembly for the ezee motor. The page indicates it's machined nylon gear, no mention of composite......I'll contact them for more info just for fun.

Jim

 

[motomech]

The gears that came in my "Cute" minis are white, but the original gears in the V1 are grey. Since both these motors were designed in the late 2000's, I would assume they are very much the same.

The blue gear is a stronger composite - nylon composite with other material? What material?

Another Mystery of the Orient. They would need to be analysed by a materials expert.

Geared motors are actually easy to work on, once the side cover is removed. The Cutes use screw-on covers and what happens w/ them is;
The force of the free wheel/cassette from pedaling tends to tighten the cover on the rears when used. They can be difficult to unscrew w/out a special tool. New motors and the frt. mounts can usually be opened w/out a special tool.
W/ my first motor, a geared MXUS mini, I could not budge the cover w/out making a tool, but I never had any reason to open it.
(On the subject of longevity of geared motors, I rode that MXUS on and off road for 6 years, sometimes over-Volting it. When I sold it cheap to a kid down the street, it was still working although I could feel the bearings getting worn. He proceeded to put a stupid amount of Volts thru it(against my advice)and last I heard, it was still working.


The larger geared motors all use flat covers that are held on by screws, 9 on my Ezee and the BMC, 6, I think, on the MAC and the BPM. Once the Phillips head screws are removed w/out stripping them(A hand-held inpact tool is recommended), a knife blade is used to gently pry them off. They are sealed with silicone.
Here is a nice pictorial Ypedal posted when he repaired an unusual ring-gear problem on a V1;

http://www.ypedal.com/ezee.htm

I'm not sure how this might apply to the V2, but the drawings on the Ebike CA site of the V1 are right-on. The drop-out width was exactly 131 mm as shown. This made fitment very easy, allowing some side to side movement to line up the brake disc. Easier even than my rear minis, most that are 136 mm's wide.
In regards to fitting your V2 w/ a disc brake, I think it might be easier than you suspect. The place where there might be interference will be the inner most spot on the inside of the caliper, that is closest to the axle center-line. Measure those distances, the distance on the vertical and the distance outboard of the vertical center-line. Then, try and interpolate from the drawing where on the sloping part of the side cover that spot might be. Even if there is contact, the fix is usually pretty easy. A larger disc and an adapter that moves your caliper further away from the whl. axle. Ck. to see if an adapter is avail. for your braking system.
After all, if you are committed to using a large geared motor, I rather doubt that any of the other brands are going to be narrower than the Ezee.

 

[motomech]

You may find this interesting;
The history of the large geared motors;
As I understand it, the Ezee was designed first(possibly in Taiwan)and a member of that team branched off and produced the BMC(There are lot's of similarities between the two).
Then the MAC was roughly cloned from the BMC.
The BPM, being a Bafang product, was of course, designed in house.
It has more differences than the other three.

 

[Jost]

motomech,

Thanks for taking time to post an in depth response with links. I'll do some more reading.

Another question, in my reading on motors, in the last couple of days, I saw pictures of a geared hub motor but the gears were helical cut. I'm assuming that's a real high end setup. Are motors with that type of gearing used in the bike world?

Jim

 

[motomech]

The heli-cut gears are used in compound systems like my Cutes. Perhaps the thought is, w/. two sets of gears, having one heli-cut pr. will keep the noise down. But they may be there to provide some side thrust.
But w/ these soft Nylon gears, I doubt there is much difference between one set of straight-cut gears and one set of heli-cut gears.