current selection of rear geared cassette hubs

[pullin-gs]

You are worrying too much about hub motor durability. I did a search here punching in "Q128" and got 25 pages of threads. Then I narrowed it down using the search-word "magnets" and ended up with 2 pages. No mention of thrown magnets.

You may want to try your search again.....
https://endless-sphere.com/forums/viewtopic.php?f=2&t=108907&p=1594176&hilit=magnets+q128c#p1594176

And another...
https://endless-sphere.com/forums/viewtopic.php?f=2&t=105249&p=1539247&hilit=magnets+q128c#p1539247

 

[motomech]

You are worrying too much about hub motor durability. I did a search here punching in "Q128" and got 25 pages of threads. Then I narrowed it down using the search-word "magnets" and ended up with 2 pages. No mention of thrown magnets.

You may want to try your search again.....
https://endless-sphere.com/forums/viewtopic.php?f=2&t=108907&p=1594176&hilit=magnets+q128c#p1594176

And another...
https://endless-sphere.com/forums/viewtopic.php?f=2&t=105249&p=1539247&hilit=magnets+q128c#p1539247

3 People out of how many of these things sold?

 

[motomech]

You are worrying too much about hub motor durability.

I'm not. I'm just too familiar with Chinese products, and how specs should always be taken with a grain of salt. All I'm doing is trying to figure out what I'm actually getting with a "48V 260 RPM" motor.

D8veh (well known ebike guru) wrote;
"There's no difference between the 36v and 48v versions - same housing, same gears, same clutch, etc, so no harm comes when you run a 36v one at 48v. They're all rated at 500w continuous, which means 1000w is OK for short periods."
He's actually a little low on the continious capability.

 

[pullin-gs]

3 People out of how many of these things sold?

3 is a whole bunch more than your lame search that found zero.
By the way, there are more than three people.
...and it happened to TWO of three motors I bought!

 

[Comrade]

D8veh (well known ebike guru) wrote;
"There's no difference between the 36v and 48v versions - same housing, same gears, same clutch, etc, so no harm comes when you run a 36v one at 48v. They're all rated at 500w continuous, which means 1000w is OK for short periods."
He's actually a little low on the continious capability.

I'm not sure about that. To get the models they sell they need 2 different windings, and 2 different sets of gears, to get 5 possible configurations that are for sale.

• 1.) 36v 201 (a)

• 2.) 36v 328 (b)

• 3.) 48v 201 (c)

• 4.) 48v 260 (a)

• 5.) 48v 328 (d)

Only #4 would over-speed the rotor compared to the other models.

 

[ZeroEm]

Like what was posted, just the windings it's the gearing also. Motors don't care about Volts. It's the amps you need to worry about. I would keep the volts just high enough to reach your speed goals. If you worry about the magnets then higher gears and lower Kv would keep motor speed down.

by Comrade » Oct 26 2021 8:14pm

motomech wrote: ↑Oct 26 2021 6:13pm
D8veh (well known ebike guru) wrote;
"There's no difference between the 36v and 48v versions - same housing, same gears, same clutch, etc, so no harm comes when you run a 36v one at 48v. They're all rated at 500w continuous, which means 1000w is OK for short periods."
He's actually a little low on the continious capability.
I'm not sure about that. To get the models they sell they need 2 different windings, and 2 different sets of gears, to get 5 possible configurations that are for sale.
1.) 36v 201 (a)
2.) 36v 328 (b)
3.) 48v 201 (c)
4.) 48v 260 (a)
5.) 48v 328 (d)
Only #4 would over-speed the rotor compared to the other models.

 

[Comrade]

So I got the motor finally. I bought the 260 RPM version of Q128C. It says "RPM:260=20inch" on the sticker.

(and 10.9 reduction ratio, also on sticker)

Plugged it in on the bench with no load, throttle to the max.

At 36V I get 193 RPM.
At 48V I get 220 RPM.

First, shouldn't the speed difference between 36V and 48V be larger? And where's my 260 RPM.? :lol:

I can't figure out what "20inch" has do with RPM either.

EDIT: I went and edited P1 on the controller, and set it to 147 (probably not totally correct) and got 250 RPM at 48V)

 

[markz]

20" vs 26" vs 29"(700C) will change the speed for the same voltage. 20" being slower then 29"
Usually you want the spec of kv (which is rpm per volt)

And what you did on the bench is unloaded rpm, when its loaded there is a rule of thumb to go by and I forget what that is, % of unloaded. I've really never cared for what kv I had for a motor as I always wanted the fastest possible, like a 3T motor of say 9-12kv, realizing that motors of different kv are the same motor with the same speed and same torque its just you need to change a few things to achieve the same. But what it coould comme down to is that a lower Turn motor caan soak up more amps bbecacaause it has shorteer,thickker windings, my keyboard or pc is aaccting uup so I need toreboot. I aint fixing those typos.

 

[Comrade]

20" vs 26" vs 29"(700C) will change the speed for the same voltage. 20" being slower then 29"

Yes, it will change the speed of travel relative to ground, but it won't change the RPM. :lol:

I'm confused why they specify "20inch" next to the RPM rating of the motor. Are they being helpful and suggesting what wheel diameter is to be used with that specific RPM rating of the motor?

 

[ZeroEm]

Unloaded speed is the same! The difference in Loaded speed comes from the larger wheel is harder to turn and the smaller wheel loaded will turn faster than the larger wheel loaded! Faster mph not just RPM's. Depends on the set up, with higher voltage this is more common.

by Comrade » Nov 20 2021 7:49am

markz wrote: ↑Nov 19 2021 11:41pm
20" vs 26" vs 29"(700C) will change the speed for the same voltage. 20" being slower then 29"
Yes, it will change the speed of travel relative to ground, but it won't change the RPM. :lol:

I'm confused why they specify "20inch" next to the RPM rating of the motor. Are they being helpful and suggesting what wheel diameter is to be used with that specific RPM rating of the motor?