How much rolling resistance is normal on X5 hub ?

Got my first 5304 hub. How much rolling resistance is normal for these ? I expected cogging but it has also quite a bit of steady resistance as if axle bearings were grossly overtightened. Certainly way more that I expected - when the bike is upside down and I stop turning pedals (by hand) the wheel stops in a fraction of a second. Is that normal or should I try to somehow adjust it ? No screeching or other ugly sounds, just very very tight.

its normal i think. i remember being initially disappointed with the resistance from my X5 compared to my last hub motor. but the X5 has no free wheel so it always has eddy currents slowing it when not powered up and connected to the controller. try disconnecting it from the controller and pedaling. this resistance should disappear when the motor is in use.

I have some experience with outrunner motor design from RC hobby. The eddy current loss is dependent on rpm and is almost absent at slow speed when I try to turn it by hand. The wheel is not connected to anything yet. A winding short will create that effect but I hope it is not the case :?. It really feels like there is some serious mechanical resistance either in the bearings or seals. Can it be adjusted somehow ?

That does sound a bit odd. Perhaps the bearings are tight and will loosen up with some use. The bearing seals have quite a bit of friction also. If there is no grinding sound, that's good. If there was a shorted winding, you would feel definite cogging when it turns.

Question for those who disassembled the hub - is there a way to loosen bearings a bit ? For example on a cheap department store bike you can loosen the bearing by turning the conical bearing nut 1/8 of a turn. Is there a way to do something similar on a hub axle ? If yes what tools do I need ?

Nope, its a sealed roller bearing, and a realy large one, too. Ebikes.ca has pictures of them.
The thing is, with that type of sealed bearing, untill it gets some wear on it, the seals add a lot of friction, but its non linear friction: it doesn't increase as the speed increases. the faster the bearing spins, the less the seal friction effets it. give it 10 hours of running time, and those seals should loosen up some. But on a Xlyte motor, it willl always stop turning after a couple of spins.

Thanks for everyone who replied. I certainly did not expect Xlyte to rotate like a freewheeling hub but still considering huge rotation mass it stops almost immediately. I do not have the controller/packs yet but I can try putting on a tire and riding a bike for a little bit and see if there is any progress. Also I can try to hook one of my RC sensorless BLDC controllers to the hub and let it run for a few hours monitoring no-load current. But if will not get any better I may consider returning it - this is way too much friction to my taste. I was expecting it to cog heavily and show considerable resistance at normal rpm due to iron losses but I was not prepared for such enormous friction loss at low rpm .

Something to keep in mind, even though that is a 25 pound chunck of iron, its an out runner. the actual rotating mass is only about 2 pounds, with the rim and tire. and the magnets are putting maybe 100 pounds of constant force on the coils. Its not going to spin free very well, ever. there just isn't enough mass in the tire to fight the cogging effects.


But that said, a properly broken in motor will not have much drag when you're riding. I've done some experiments with coasting my Ebike next to my girlfriends non powered bike. While I can feel a slight diffrence between my bike with and without the motor, they both maintain the same speed while coasting, and travel the same distance. actualy pedaling it will feel like strapping a 25 pound package to your bike and riding it with the back tire 10 pounds low on pressure.

Ok, I hooked a sensorless RC controller (CC80) to the hub. The no load current at 24V is about 2.3A which makes it about 55W. The number is reasonable so I guess I'll live with that. While running it I've noticed there is also some eccentricity in the hub so the sprockets move about 0.5mm-1mm every turn. Not really impressive precision but I guess it should still work.

I had the same problem and justin at ebikes had to machine away some of the outer casing because the bearings were rubbing.You should have yours checked out or return it.The X5 does suck for rolling resistance especially when you compare it to a 400 series.But this is the trade off for better torque.Ask justin what the proper load is.He has experimented with this probably more than anybody.

Hope this helps.

I've got mine from US store, but I'll drop Justin an email. He probably knows what the now load current is normal for these since they did the sim.

curious said:

Ok, I hooked a sensorless RC controller (CC80) to the hub. The no load current at 24V is about 2.3A which makes it about 55W. The number is reasonable so I guess I'll live with that. While running it I've noticed there is also some eccentricity in the hub so the sprockets move about 0.5mm-1mm every turn. Not really impressive precision but I guess it should still work.

Click to expand...

Cool. 2.3A sounds about right.

How does the sensorless controller work out? In particular, how does it behave when starting up from a dead stop? I've always wanted to do a big sensorless controller and eliminate those pesky hall sensors.

Hey Curious

I thought i would just join the bandwagon and let you know that defiantly doesn't sound right. My X5304 doesn't spin all that well compared to a freewheel but i get at least about 6+ wheel rotations when i give the wheel a spin before the magnet forces stop it.

I originally had a problem with the chain tensioner rubbing up against the hub and I added two spaces between the hub and the gears to try and fix it (it hasn't completely solved my problems), but in doing that the gears started rubbing against the drop out causing the same sort of symptoms. I ended up putting washes in between the hub and drop outs and it seemed to solve the problems.

I eventially fried CC80 80A controller trying to demo the hub to a friend . The start-up is very rough and even though I've got it running fine many times by myself during the demo I put freshly charged batteries it kicked pretty hard and possibly overspeed the wheel such that back-emf fried the controller fet diodes (this particular controller is marginal at 24V). Anyway no more RC controllers here .

I do not recommend sensorless controllers. A sensorless controller does not know the phase of the motor until it reaches certain rpm and drives it basically as a synchronous stepper motor slowly increasing rpm until back-emf detection starts working. At least in theory. In practice it sometimes kicks back and forward a bit before starting. Not pretty really. If you need smooth torque during startup this is not a solution.

BTW I got a reply from Justin saying that the no load current for 5304 is typically 1.2A-2A at 36V so I am definitely on the high end. He suggested to loosen the hub case screws by few turns and checking if it gets any better which I will do this week.

Fush said:

My X5304 doesn't spin all that well compared to a freewheel but i get at least about 6+ wheel rotations when i give the wheel a spin before the magnet forces stop it.

Click to expand...

I am nowhere near that. But there is no external rubbing. I think it is the issue of excessive sideways case pressure on the hub bearing.