Geared Hub - Speed Sensor?

General Discussion about electric bicycles.
Post Reply
davekkk   100 µW

100 µW
Posts: 8
Joined: Sep 07 2020 7:38pm

Geared Hub - Speed Sensor?

Post by davekkk » Jan 26 2022 11:12am

Picked up a generic geared front fat wheel/motor on a Ali Express sale. Never seen anything like this though. I asked the seller and they said its a sensor. But to me it looks like two screws glued to the inside of the case, doesnt go through.

Anyone else seen this? I searched and searched without luck. I am worried if these fall off, its just going to take out the whole inside of the motor.

Link to product:
https://www.aliexpress.com/item/1005002 ... 4c4d2mloJu

I regressed, Lucas.
Attachments
IMG_8205.JPG
Pic1
IMG_8205.JPG (127.44 KiB) Viewed 343 times
IMG_8202.JPG
Pic2
IMG_8202.JPG (243.47 KiB) Viewed 343 times
IMG_8234.JPG
IMG_8234.JPG (2.42 MiB) Viewed 303 times
IMG_8232.JPG
IMG_8232.JPG (2.58 MiB) Viewed 303 times
IMG_8237.JPG
IMG_8237.JPG (2.77 MiB) Viewed 300 times
IMG_8267.JPG
IMG_8267.JPG (165.96 KiB) Viewed 220 times
IMG_8255.JPG
IMG_8255.JPG (180.39 KiB) Viewed 220 times
IMG_8274.JPG
IMG_8274.JPG (230.31 KiB) Viewed 220 times
IMG_8258.JPG
IMG_8258.JPG (282.79 KiB) Viewed 220 times
clutch.PNG
clutch.PNG (2.78 MiB) Viewed 220 times
IMG_8256.JPG
IMG_8256.JPG (224.81 KiB) Viewed 220 times
Last edited by davekkk on Jan 27 2022 4:23pm, edited 4 times in total.

User avatar
amberwolf   100 GW

100 GW
Posts: 33715
Joined: Aug 17 2009 6:43am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: Geared Hub - Speed Sensor?

Post by amberwolf » Jan 26 2022 6:57pm

Looks like they turned a regular hubmotor into a fatbike motor by using a wider shell, but designed it wrong and then needed something to get the magnets for the speed sensor close enough to the hall sensor board to trigger it...and came up with that. :roll:

If you don't need the speed sensor, you can take those screws off of there. The "glue" looks like some epoxies do, but if it's not made for high temperatures, then when the motor gets hot enough it'll soften, and if impacts or vibrations were of sufficient force, they could be dislodged over time. No way to find out other than actual testing in worst-case circumstances that you might encounter. :/



The right solution, if they *had* to use screws, was to drill holes in the cover and bolt them to it from the outside, with proper locking hardware on the inside to keep the nuts from ever coming off (even a dimple in the thread would do that, even if it didn't keep them tight).

Might still work fine as-is, forever...but not knowing what glue they used, I have a hard time trusting a hackjob design like that (I do this stuff all the time on my own projects...but I wouldn't do it on something mass produced). The likelihood of them using the right glue for it is medium to low...cost and all that, aside from possibly not having any idea what it needs to handle. Plus if they didn't properly clean the inboard side of the side cover first, then it's glued to oxidized metal, possibly even dirty metal or corroded metal (note the white dots around the inside of that cover). Can't accurately predict results even of the right glue with those conditions.

Do you have a link to the seller?

Pics of the rest of the motor (outside casing, labels/markings, etc) would be interesting, too.
If you found this advice helpful, supporting contributions are accepted here.

Beginning of a New Life


Give a listen to my music!

(More here, including experimental)
.

davekkk   100 µW

100 µW
Posts: 8
Joined: Sep 07 2020 7:38pm

Re: Geared Hub - Speed Sensor?

Post by davekkk » Jan 26 2022 8:14pm

I added a few more pics and a link to the seller. I didnt get any more pictures of it while I had it apart.

While I was not expecting Bafang quality, I was hoping for at least Ebikeling quality. I have a fat rear 500w geared kit from them (and several other ebikeling kits for other bikes) and they have been pretty good. But Ebikeling seems to have gotten out of the geared hub game for fat bikes.

I pulled it apart to check grease right away before installing and that is when I found the weird stuff inside. It sounds ok sitting on some drop outs, pretty quiet. That is pretty annoying though, I really need to stop buying stuff on the Ali sites, second time I got burned! I'll probably pull the bolts out because I just dont trust them. I doubt I'll get any refund but I'll ask.

User avatar
E-HP   1.21 GW

1.21 GW
Posts: 3737
Joined: Nov 01 2018 9:20pm

Re: Geared Hub - Speed Sensor?

Post by E-HP » Jan 26 2022 9:18pm

davekkk wrote:
Jan 26 2022 8:14pm
I added a few more pics and a link to the seller.
Off topic, and I'm no expert, but that's an interesting lacing pattern on that wheel. I've was looking at a lot of laced motors, since I was doing my first. Is there an advantage?

calab   100 kW

100 kW
Posts: 1209
Joined: Dec 11 2013 1:00am

Re: Geared Hub - Speed Sensor?

Post by calab » Jan 26 2022 9:56pm

What is interesting about it? the elbows arent the same (one is elbows in the other is elbows out) so its dished or is there something I am missing?

I have not laced a wheel in a long long time, but the offset is wide between the left side nipple holes and the right side nipple holes, and I do believe the flange is right and its skipped every one on the rim. I still dont see it, wheres waldo :lol:


E-HP wrote:
Jan 26 2022 9:18pm
davekkk wrote:
Jan 26 2022 8:14pm
I added a few more pics and a link to the seller.
Off topic, and I'm no expert, but that's an interesting lacing pattern on that wheel. I've was looking at a lot of laced motors, since I was doing my first. Is there an advantage?

User avatar
E-HP   1.21 GW

1.21 GW
Posts: 3737
Joined: Nov 01 2018 9:20pm

Re: Geared Hub - Speed Sensor?

Post by E-HP » Jan 26 2022 10:28pm

calab wrote:
Jan 26 2022 9:56pm
What is interesting about it? the elbows arent the same (one is elbows in the other is elbows out) so its dished or is there something I am missing?

I have not laced a wheel in a long long time, but the offset is wide between the left side nipple holes and the right side nipple holes, and I do believe the flange is right and its skipped every one on the rim. I still dont see it, wheres waldo :lol:


E-HP wrote:
Jan 26 2022 9:18pm
davekkk wrote:
Jan 26 2022 8:14pm
I added a few more pics and a link to the seller.
Off topic, and I'm no expert, but that's an interesting lacing pattern on that wheel. I've was looking at a lot of laced motors, since I was doing my first. Is there an advantage?
Like I said, I'm a novice. I've never seen all the spokes on one side on the inside, and the other side out. I see alternating, and I've seen all on the inside or all on the outside, that's all. Sounds like you've done some, at least in the past, so more experience.

calab   100 kW

100 kW
Posts: 1209
Joined: Dec 11 2013 1:00am

Re: Geared Hub - Speed Sensor?

Post by calab » Jan 26 2022 10:36pm

I see but yeah it can be alternating, it can be both flanges inside, or both flanges outside. I laced a half dozen rims and I do elbows inside so the spoke doesnt have to bend over and around the flange with elbows outside, thats with normal rims not a problem with the op.
Fat rims the nipple holes are offset. My bet is the rim and spokes are crappy generic and its always wise to buy just the hub motor and lace it but that scares many people away so they buy the hub already laced so put up with it for as long as it lasts then rebuild it with brand name rims, spokes and nipples.
E-HP wrote:
Jan 26 2022 10:28pm
Like I said, I'm a novice. I've never seen all the spokes on one side on the inside, and the other side out. I see alternating, and I've seen all on the inside or all on the outside, that's all. Sounds like you've done some, at least in the past, so more experience.

User avatar
E-HP   1.21 GW

1.21 GW
Posts: 3737
Joined: Nov 01 2018 9:20pm

Re: Geared Hub - Speed Sensor?

Post by E-HP » Jan 26 2022 10:50pm

calab wrote:
Jan 26 2022 10:36pm
I see but yeah it can be alternating, it can be both flanges inside, or both flanges outside. I laced a half dozen rims and I do elbows inside so the spoke doesnt have to bend over and around the flange with elbows outside, thats with normal rims not a problem with the op.
I did all the elbows on the outside; supposedly is stronger laterally, who knows. I think any way you lace them, there's some trade off, at least with the options available when the hub diameter gets bigger. They say more crosses makes the wheel stronger under power or braking, but hard to do more than one or two cross with a motor. After I was done, I thought to myself, this will be more difficult if I break the wrong spokes. Lesson for next time. :cry:

It looks like lacing that way could be really efficient since you could put all the spokes in on both sides, without flipping the wheel over, and then place it down on it's side and start the lace for the whole rim, again without having to flip it over. Then put it on whatever truing stand you're using.

calab   100 kW

100 kW
Posts: 1209
Joined: Dec 11 2013 1:00am

Re: Geared Hub - Speed Sensor?

Post by calab » Jan 27 2022 12:37am

Well it all depends you could have a small hub in a big 29/700 rim or a big hub in a small 20" rim.
You dont want to the rim to be rigid and solid and you dont want to use big thick spokes you want the rim to flex.
If someone out there is going to lace a hub there are lots of great videos out there, its just a matter of taking it slow and doing things methodically step by step and most of all getting all the information from the hub and the rims erd. Its pretty easy to measure both, I just measured a sturmey archer i.g. hub to put into the smallest rim but they are 20h an 28h the sturmey is 36h.

I still dont understand those bolts, and I have read the post by amberwolf and looked at the pictures many times.

User avatar
Chalo   100 GW

100 GW
Posts: 10416
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Geared Hub - Speed Sensor?

Post by Chalo » Jan 27 2022 2:54am

E-HP wrote:
Jan 26 2022 10:28pm
I've never seen all the spokes on one side on the inside, and the other side out. I see alternating, and I've seen all on the inside or all on the outside, that's all.
When I lace a hub motor that has offset flanges, I almost always lace it that way-- all the spokes laced opposite the direction of the offset. It goes a long way towards getting more tension on the loose side and less on the tight side.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

davekkk   100 µW

100 µW
Posts: 8
Joined: Sep 07 2020 7:38pm

Re: Geared Hub - Speed Sensor?

Post by davekkk » Jan 27 2022 10:40am

I didnt notice the spokes till now, interesting. I am wondering if the wheel is safe to use like this.

I am wondering if there is any chance they took a rear standard bike kit and fit it in a front wide shell. Is this possible I wonder?

docw009   1 MW

1 MW
Posts: 1679
Joined: Aug 02 2015 7:43am
Location: Chicago area suburbs.

Re: Geared Hub - Speed Sensor?

Post by docw009 » Jan 27 2022 2:18pm

While the tutorials for standard hubs/rims specify alternate elbows, I found that with shorter spokes, doing them all in the same direction on a 20" rim allowed the spokes to touch at the crossing, Isn't that the idea, to have them touch at the cross?

User avatar
Chalo   100 GW

100 GW
Posts: 10416
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Geared Hub - Speed Sensor?

Post by Chalo » Jan 27 2022 3:28pm

docw009 wrote:
Jan 27 2022 2:18pm
While the tutorials for standard hubs/rims specify alternate elbows, I found that with shorter spokes, doing them all in the same direction on a 20" rim allowed the spokes to touch at the crossing, Isn't that the idea, to have them touch at the cross?
Interlacing the last crossing (on normal bike wheels) offers two advantages: it allows the spoke that gets tighter under torque to take up any slack that appears in the crossing spoke that gets looser. (This is really only an advantage for a wheel that's very loose or marginal for its load.) The second advantage is that interlacing the spokes tends to keep them trapped more or less in place when they break.

Neither of these factors applies to a hub motor laced in a cross-1 pattern. You can't interlace cross-one spokes, because it would kink the spokes sharply at the crossings.

However, you can lace cross-1 spokes all on one side of the flange. That's not practicable with higher cross counts, because again it would cause spokes to be kinked sharply at the first crossing.

By using all-one-side lacing, you can in effect move the average spoke line about 4mm to one side or the other. You can use this effect to reduce wheel dish, increase bracing angle, or reduce aero cross-section. Because hub motor wheels have narrowly spaced flanges, they are particularly vulnerable to weakness and unreliability due to dish, and even small changes in offset have a disproportionate effect on wheel integrity.

When manufacturers lace hub motors with all elbows in, which is common, they give you the worst possible qualities-- minimum spoke bracing angle, maximum effect of wheel dish. The only advantage I can see is that broken spokes will tend not to fly out and snag on stuff.

Generally speaking, if a hub motor has symmetrically located flanges (which is somewhat rare anymore), it should be laced with all elbows out, for the best bracing angle. If it's asymmetrical (dished), then lace all the spokes to counter the flange offset.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

AHicks   10 kW

10 kW
Posts: 630
Joined: Jul 24 2018 10:53am
Location: Snowbird

Re: Geared Hub - Speed Sensor?

Post by AHicks » Jan 27 2022 4:04pm

Regarding the single cross lacing pattern, it has to do with the angle the spoke is meeting the wheel at. For instance, you don't want extreme angles, like you would have if the setup shown were done in a triple cross. Bottom line, it has to do with the spoke length necessary. Single cross not that unusual at all, especially concerning larger hubs or smaller wheels.

Nothing wrong with what's going on with the spokes in the pictures - that I see anyway.

Post Reply