Spare Oxygen eMate Rear Wheel

[Warwick]

I love my Oxygen. I'm commuting on it through the winter & it's quicker than the car.

I have spiked tyres on it at the moment, and the weather is rather changeable. On my other non-powered MTB I have a spare set of wheels with knobblies & city tyres on them and I can swap over quite easily to adapt to the vagaries of the weather.

Is it worth having a spare rear wheel built up? Where would I get a motor from? It's the RWD version, 250W/36V. I'm already having a dynohub front wheel built up.

 

[Deleted member 4366]

There's different versions, but all should be compatible. You can use any motor with the 9-pin connector.

Cassette motors:
Q100C
Q128C
Bafang SWX02C
Bafang CST 250w/350w
MXUS XF08C

You can use more or less any freewheel motor if you don't mind going down to 7 speed gears.

Chinese suppliers are:
BMSBattery.com
Elifebike.com
Greenbike kit.com
BTN (Aliexpress)
Aliexpress search

UK suppliers normally sell only kits, but they might have an odd motor-wheel they'd sell. Try Woosh and Ebay.

 

[Warwick]

I'd definitely want to keep the 9-speed cassette to be able to have a straight swap.

Is one more reliable than the others?

 

[Deleted member 4366]

Is one more reliable than the others?

Not really. The Q128C is very strong. I think the Bafangs let in a bit of water if you're not careful. the MXUS is not quite as powerful.

I think I'd go for the Q128C but now there's another problem - maybe. 201 RPM is OK if you want to keep it restricted, and 328 RPM is probably a bit too fast unless you're light weight and have a light bike. Best is the 201 RPM 36v one at 48v, but that needs a 48v battery and controller.

The MXUS and Bafangs have the right speed at just over 20 mph.

Nothing is straight-forward is it!

 

[Warwick]

Right, thanks. I'm running unrestricted and weigh 85Kg. I'm happy at 20-25MPH and don't want silly speeds.

Assuming I have to buy in from China, how much does the VAT/HMRC add on to the price?

 

[Nealh]

Bmsb deliveries come via Fedx or DHL, Fedx they are hot on charging and invoice within 3 weeks about £25-30 ( I was charged) with DHL I have never had a charge. The carriers (some) do the work for the HMRC supposedly.
My Q128c came marked as a 201/36v but was fast on the road 26/27 mph , so was marked up wrong and must be a 328. So beware you may not get the right speed motor even if you expressly ask for it, this is also bore out by remarks on ES. Another option I suppose is to get a 48v/328 and run it at 36v thereabouts you should get a 260 ish rpm speed.

 

[Deleted member 4366]

Another option I suppose is to get a 48v/328 and run it at 36v thereabouts you should get a 260 ish rpm speed.

Good point!

 

[jhruk]

.
My Q128c came marked as a 201/36v but was fast on the road 26/27 mph , so was marked up wrong and must be a 328. So beware you may not get the right speed motor even if you expressly ask for it, this is also bore out by remarks on ES. Another option I suppose is to get a 48v/328 and run it at 36v thereabouts you should get a 260 ish rpm speed.

I bought a 48v/328 Q128c from BMSB but found this also ran faster than I was expecting.
It was correctly labelled but ran at a no load speed of around 29mph at 41v in a 700c wheel rather than the 22/23mph I was hoping for. This would suggest it's also a 36v/328 motor, the same as you received.

Perhaps they only have one version and just stick different labels on them.

 

[Nealh]

I bought a 48v/328 Q128c from BMSB but found this also ran faster than I was expecting.
It was correctly labelled but ran at a no load speed of around 29mph at 41v in a 700c wheel rather than the 22/23mph I was hoping for. This would suggest it's also a 36v/328 motor, the same as you received.

Perhaps they only have one version and just stick different labels on them.

Your hub sounds like it was correctly marked and the NLS run at 36v sounds about right for that hub. A 328/48v run at 36v would have you a rpm of 260ish and a road speed of about 22/23 mph.
I didn't check the NLS in the 26" wheel I had it in but the actual on the road speed at 26mph @36v with proper mtb knobblies was not the expectant result I was hoping for and wanted it for slower torque climbing. I have just laced it into a 700c rim so when I get round to it will see what the NLS speed is and expect the road speed to be about 28mph.

 

[jhruk]

Your hub sounds like it was correctly marked and the NLS run at 36v sounds about right for that hub. A 328/48v run at 36v would have you a rpm of 260ish and a road speed of about 22/23 mph.
I didn't check the NLS in the 26" wheel I had it in but the actual on the road speed at 26mph @36v with proper mtb knobblies was not the expectant result I was hoping for and wanted it for slower torque climbing. I have just laced it into a 700c rim so when I get round to it will see what the NLS speed is and expect the road speed to be about 28mph.

I’ve calculated my motor is about 310rpm at 36v, which is way above the 246rpm(328*0.75) I was expecting, although not quite 328rpm.

Like you I was hoping for better hill climbing in exchange for speed. In use I find it ok but feel it would have been nicer with lower gearing. I also have a 260rpm Mxus and find them about equal for climbing with the same 17a controller.

 

[Warwick]

Forgive my ignorance, but could I run a 48v motor using a 36V battery and 36v controller? What I'm after is a quick 10-minute wheel swap without anything else to worry over.

 

[Woosh]

Hi warwick,

Have you thought of asking Oxygen how much they charge for a replacement motor wheel? It may be simpler to get one from the UK with full warranty.

 

[Nealh]

Yes is the answer Warwick. Though you have to get a hub marked with a faster speed code/wind then you require as your battery/controller will provide on average 30% less speed.
Commonly only a few motor cst speeds are available in 36 or 48v and tend to be listed as such which tend to be Q's list them 201 & 328 and Bafangs 192,201, 205, 270 & 328.
A Q 328rpm 48v hub run at 36v will give you an approx. average rpm of 260 though the rpm values will change depending on the charge state also the advantage of a lighter motor wheel.
Using nominal battery voltage 48/36v you end up with approx. 246 rpm but hot off the charger values 50.4/42v you end up with approx 273 rpm which should be good for 22/23 mph.
With the (10) 270 bafang a 48v one will be about 201 rpm @36v.
Interpreting the speed codes is not a given fact though there are some threads on ES where as assumptions from Bafang data has been interpreted.

 

[Warwick]

Yes, I've approached Oxygen without luck so far. I thought I'd explore other, probably cheaper, options as well.

Thanks for the guidance everyone.

 

[Nealh]

Q128 cst delivered and duty paid will be about £165 +/- £10 or 140 ish if you don't get clobbered for duty.
Bafand cst circa 290 delivered and duty paid both from BMSB and bare motors.
Oxydrive sell the cst for about 250 in a rim.
All options are 350/500w.

 

[Warwick]

If those prices are for the motor only, I'll try calling Oxydrive. They're out of stock at the moment, so the time may pass before winter's out.

 

[Nealh]

Yes bare hub prices from China, would be a bit pricier in rim as weight and parcel size s more.

 

[Warwick]

I'm still pondering whether to do this, but I thought I'd point out that neither Oxydrive nor Oxygen bothered to respond to my requests for a price, using their web contact forms...

Disappointing.

 

[Deleted member 4366]

As I said, you can use any motor. Buying a motor as a spare part from an OEM bike would be a very expensive way to do it. I can imagine that most dealers wouldn't want to do that because they have no idea what controller or battery you'd use, which would bring all sorts of problems if the motor didn't work.