Q100C CST rolling resistance / friction?

My brand new Q100C CST motor from BMS Battery seems to have a lot of rolling resistance. There is like a friction sound when I spin the wheel by hand.

My previous build has a Q100H and it spin freely without any kind of resistance/friction...

Is it normal (break-in period?) or should I try to exchange the motor with BMS Battery?

Video:
[youtube]zOubH5zmtTc[/youtube]

Thanks!

I really can't tell anything from the video.
It should free wheel like your H model.
What happens when you power it up?
Pretty easy to open a Cute motor up and have a look at the clutch/gears.
My experience with BMS Battery is, they never take anything back, but that doesn't mean they won't send you another if you prove to them something is wrong.
Perhaps the shipping from Japan is reasonable enough to make returns feasible.

motomech said:

I really can't tell anything from the video.
It should free wheel like your H model.

Click to expand...

On the first video you can hear a friction sound and see that the wheel doesn't spin very long. I've made a comparison video between my old Q100H and my brand new Q100C CST, maybe it will be more clear? I really don't know if this is normal for a brand new motor?

[youtube]a96wRJ2Rzis[/youtube]

motomech said:

What happens when you power it up?

Click to expand...

When I power it up, the motor seems to run fine (not tried on the road yet) and the LCD screen shows a consumption of 30-40 watts without any load.

motomech said:

Pretty easy to open a Cute motor up and have a look at the clutch/gears

Click to expand...

I've tried to open the motor yesterday but without any success (not really sure how to proceed). I'm also worry to damage it if I need to return it at some point. Maybe you have some tricks to remove the cover without damaging it?

Thanks!

https://endless-sphere.com/forums/viewtopic.php?f=2&t=50840&p=752553&hilit=cute+clutch#p752553

The hardest part is removing the 3 Phillips screws in the side cover wiothout damaging the slots. It is best done with a hand-held impact driver, an inexpensive tool.

motomech said:

https://endless-sphere.com/forums/viewtopic.php?f=2&t=50840&p=752553&hilit=cute+clutch#p752553

The hardest part is removing the 3 Phillips screws in the side cover wiothout damaging the slots. It is best done with a hand-held impact driver, an inexpensive tool.

Click to expand...

Thanks for the link! Wasn't that easy to unscrew the outer part (I've even bended a screw in the process).

Looks like the friction is coming from either an excess or a bad grease inside the clutch. I've just ordered some Mobilgrease 28 (was not easy to source in Japan), I hope it will do the trick.

Since I have the motor dismantled, I'm also thinking the replace the grease on the gears, any advice to:
1) unscrew the plate that hold the gear (couldn't do it with a screwdriver, seems completly stuck)
2) remove/wash/clean the original grease

To loosen the screw, try an impact screwdriver. Search eBay for one of these: Vessel Megadora Impacta 980 P3 x 150 Screwdriver - JIS #3 Cross Point & Phillips

I'm not sure if that's a #2 (P2) or #3 (P3).

dahu33 said:

motomech said:

https://endless-sphere.com/forums/viewtopic.php?f=2&t=50840&p=752553&hilit=cute+clutch#p752553

The hardest part is removing the 3 Phillips screws in the side cover wiothout damaging the slots. It is best done with a hand-held impact driver, an inexpensive tool.

Click to expand...

Thanks for the link! Wasn't that easy to unscrew the outer part (I've even bended a screw in the process).

Looks like the friction is coming from either an excess or a bad grease inside the clutch. I've just ordered some Mobilgrease 28 (was not easy to source in Japan), I hope it will do the trick.

Since I have the motor dismantled, I'm also thinking the replace the grease on the gears, any advice to:
1) unscrew the plate that hold the gear (couldn't do it with a screwdriver, seems completly stuck)
2) remove/wash/clean the original grease

Click to expand...

Grease, being basicly just oil and soap, doesn't "go bad".
And the importantce of using some special grease is a function of how much heat and pressure are generated in the component where grease is used.
Not much heat and pressure in a Cutie motor.
The grease is there primarily to prevent rust and keep the Sprage mechanism working smoothly. The nylon gears are to some extent, self-lubricating.
Since you don't see anything obviously wrong, I would suggest you re-assemble and use it.
Do put extra grease on the threads of the side-cover to facilitate opening it again later.
Semi-hard thread locker on the 3 screws that secure it.

I just did the same test with my Q100 cst 201 rpm motor I bought from BMS battery several months ago .

In fact it is worse, the motor is not yet build up ( laced ) to a rim yet, and it hardly turns at all !

Mine is only turning one revolution, it looks like yours is turning 3.5 to 4 revolutions .

Do you have the 201 rpm one ? when did you buy it, and/or serial number on it ?

Please keep us posted on what BMS tells you, and what others are reporting .

With the Mobilgrease 28 in the mail and the motor half disassembled, I couldn't resist... I've cleaned every pieces re-greased everything...

The result is as expected, not much improvement... The motor has slightly less resistance and is maybe a bit less noisy but nothing worth the amount of work that was required to replace the grease. I would not do it a second time (although I learned a lot of things in the process).

I hope the rolling resistance will go away after riding the bike for a bit. I will try to update this thread after 100km, but I still have a lot of work to do before hitting the road...

Thanks all for your valuable advices!

Same here (Q100 motor not laced yet). My first thought was it is the resistance from the seals of the bearings, but it seams a little much for just that. Maibe a combinatiuon of that and the resistance of the gears.