Rear hub motor choice

[jbond]

Decisions. Decisions. Which would make a better base for a stealth 48v-15A rear drive motor on a bike with mechanical 160mm disks and Shimano Acera 9sp rear mech? The Cute/QBK 10 CST using the existing 9 speed cassette, or the Bafang/8Fun SWXH with a DND 9sp freewheel. The Cute has a LHS cable exit which might be a bit neater. And the CST using the existing cassette which might fit and work better with the existing drop outs and mech. Conversely the Bafang might be more robust and cope better with being overdriven. There may be some differences in disk clearance, spoke dishing required, drop out width and so on.

The bike is a Genesis Tour de Fer. Road touring bike with 700-35c Marathons.

Anyone got any direct experience of the comparison?

GBK-100CST 36V 250W e-bike cassette freewheel kit http://www.greenbikekit.com/electric-bike-kit/rear/100cst-cassette-freewheel-e-bike-kit-36v-250w.html
Bafang SWXH 36V 250W Rear driving conversion kit http://www.greenbikekit.com/electric-bike-kit/rear/bafang-swxh-250w-36v-rear-driving-e-bike-conversion-kit.html
9SP DNP 11T FREEWHEEL http://em3ev.com/store/index.php?route=product/product&path=41_56&product_id=113

 

[Deleted member 4366]

Nothing is straight-forward. The Q100c is quite wide and needs a sizeable dish in the rim. It's the same when fitting an 8 speed DNP freewheel. I can imagine a 9 speed being even worse, so you need to check the actual stack height. I haven't fitted one myself, but I heard that the Q128c is better in that respect.

I haven't used GBK controllers for years, so I'm not sure which ones you get now. I always use BMSB because their KT controllers are very good.

 

[jbond]

Interesting that on endless sphere, the first comment recommended the Q128 with the usual "more is better" view. My current ride is an Alien Aurora with the big BPM motor. What I'm trying for is a better quality bicycle that's lighter and more discreet but with about the same performance or a little more. And I was encouraged by a recent sale ad on here for a Q100CST wheel.

I can see I'm now heading down the rabbit hole of research again. Not least because the various suppliers don't necessarily have all the options available. This week. Next week they might.

I was planning on getting the controller and battery from EV3EM as they do suitable 6-FET controllers with upgraded FETs for a ~50v system.

 

[Cottonpickers]

Hi - I think you may be referring to the kit I picked up from Amigafan.

I came from a BPM on a ~22kg Kudos Tornado (great bike - highly recommend it) but after a few years and 4,000 miles I wanted a lighter bike discreetly powered - so pretty similar requirements.

I put the kit on a Trek FX S4. (10.5kg without the kit) - Amigafan recommended the trek with carbon forks and I have to say its a great call. I haven't weighed it now but the motor should be 2.1kg and the battery is 1.5kg so overall a fair chunk lighter. I bought a new 10spd cassette for the Q100C wheel so I can retain a non motored wheel (I will put tube and tyre on it so I can swap if I ever want a fully non powered bike) I commute 14m each way so the bags and mudguard weren't optional! The controller and one of the 4ah 63v batteries sit in the small bag leaving the large empty bag for work stuff.

I'm delighted. its easy to ride quickly and the motor works as well/better than the BPM for my ride. My first commute used 1.55ah each leg of the 14m journey which surprised me. Previously I would charge the 10ah 36V Kudos battery at work and home and when I recently checked it was at 30% at the end of the home leg. Voltage sag meant it felt like it was closer to 10% left. The 15S lipos don't have that issue at all so it feels peppier throughout the run right til it hits the end. I plan to charge at work (but I need a quiet, discreet charger). I could average the same speed as I did with the Tornado on full power, but it seems more fun - the flats I can ride unassisted at 17-18mph which I couldn't do before, then the motor powers up the hills easily.

Roadside view:

Kerbside view

I would think you could get away with 48V and those combined bottle/controller for a nice easy conversion, but I'm happy with the build I have.

Only issue installing was the freewheel clicking/clanking even with motor off. Turned out that the round wire that holds the three rathets in place had moved and needed reseating (easy once I worked out what was happening)

Since doing this build its got me wondering if people have been successfully building a Q85 into a 700c and overvolting it for an even lighter ride. I don't feel I need any more power on this one.

 

[Deleted member 4366]

The Q100's are powerful little motors. The Q100H gives the most power because of its lower internal ratio, which makes the rotor spin faster. Both the rotor and stator are wider than the Q100C, so it makes more torque for equivalent rotor speeds. The Q128 is like a Q100 on steroids. It's 1 kg heavier, but a lot more powerful and robust.

Too much choice!

 

[anotherkiwi]

I'm looking for a new home for the mxus now and unfortunately the neighbour rode up on this...

Lapierre speed 400

A thing of beauty (to the eye of the beholder) Just missing an NCX and a better saddle and a HS11 on the front. I think I would go the whole hog and put the RST mono-shock fork on the front too.

While on the subject of rear hubs and freewheels - is there a European source for DNP Epoch Freewheels? All the ones I can find are in the USA...

EDIT Never mind sjs has them

 

[Deleted member 4366]

For me, no disc brake means move on to the next candidate. It looks quite heavy too.

 

[anotherkiwi]

There is a disk brake version (speed 600) but the HS11 on the front will be lighter and it is not a heavy bike, lighter than the Decathlon one I am looking at in any case.

 

[jbond]

Is there a UK supplier who can source the Cute/QBK 10 CST in a 700c wheel?

 

[Deleted member 4366]

No.

The Q100 is a clone of the Aikema motor used in the Wisper Torques, so see if you can get one from Wisper as a spare part. Check that it's the cassette version.

 

[jbond]

Does raise the question, again, of why there's no UK/EU supplier equivalent of BMSBattery and Greenbikekit that can source the most common 8fun and Cute motors, wheels and bits and pieces. Even on eBay. Going direct does work, but shipping takes ages and costs a lot. And you always seem to get caught on the VAT/Import taxes.

Or is there a reliable European source and I just haven't found it yet?

 

[anotherkiwi]

Bafang won't talk to anyone at less than half a million dollars (I quote one of the Americans).

So you will be paying more for stock and higher wages and rent and... There are some very good EU sources but they are much more expensive than BMS Battery.

 

[Wisper Bikes]

No.

The Q100 is a clone of the Aikema motor used in the Wisper Torques, so see if you can get one from Wisper as a spare part. Check that it's the cassette version.

No problem with the supply as a spare part, on or off wheel.

All the best, David

 

[mechaniker]

Does raise the question, again, of why there's no UK/EU supplier equivalent of BMSBattery and Greenbikekit

I suggest you open a shop for this items and then you will know why.....
Honestly dealing with china manufacturer isn´t easy and when you deal with it in europe you must give warranty. Over the last 10 years I´ve seen a lot of companys come and go and all of them thought it would be easy to earn money with this e-bike item´s but it is far away from easy.

Main problem is stupid customer (sorry to say so but it is a fact)
quality of what you get from the manufacturer. Deliverproblem´s and more....
Stupid manufacturer in China which don´t give warranty (let´s say as a dealer you have 100 brocken motors but the manufacturer accept only a few as warranty....)
A China based company simply don´t react on customer-complain but as a european based company this behaviour is not possible for you.
You have to deal with the european customer who want china-price and european warranty which is simply impossible to make.
and a lot of other reason´s why it is a difficult business which I would never suggest to anybody


frank

 

[Deleted member 4366]

Main problem is stupid customer (sorry to say so but it is a fact)

I was going to say the same. The customer can:

• use the wrong controller
• connect his throttle incorrectly that can blow the hall sensors in the motor
• damage the wires with a too tight cable tie
• mount the motor inverted so that water goes in
• leave out the disc screws to let water in
• try and use the motor like a motorbike, which damages gears or burns it
• overvolts it to burn it
• Break his throttle and not have brake cut-offs, so tries to stop the motot with his brake, which burns it
• not use a torque arm - axle spins and gets damaged
• falls off or otherwise damage the cable
• gets the wrong hall/phase sequence connection on his controller

That's just the motor. Think about all the things that he can do with his controller, throttle ans PAS!

I only sold a few motors to people on the forum and a few controllers on Ebay. I must have spent as long as three hours dealing with queries from single customers. I couldn't keep up with them. That's for a normal reliable motor, which many of us would just fit and forget.

I think BMSBattery, with the way they blank you if you raise a query after you bought something, got it about right. they probably make a profit and get to watch TV at night. That wouldn't work in the UK.

I bet all the UK kit sellers are wondering if it's worth it!

 

[Woosh]

I suggest you open a shop for this items and then you will know why.....
Honestly dealing with china manufacturer isn´t easy and when you deal with it in europe you must give warranty. Over the last 10 years I´ve seen a lot of companys come and go and all of them thought it would be easy to earn money with this e-bike item´s but it is far away from easy.

Main problem is stupid customer (sorry to say so but it is a fact)
quality of what you get from the manufacturer. Deliverproblem´s and more....
Stupid manufacturer in China which don´t give warranty (let´s say as a dealer you have 100 brocken motors but the manufacturer accept only a few as warranty....)
A China based company simply don´t react on customer-complain but as a european based company this behaviour is not possible for you.
You have to deal with the european customer who want china-price and european warranty which is simply impossible to make.
and a lot of other reason´s why it is a difficult business which I would never suggest to anybody


frank

We do all the motor repairs in Southend on Sea.

 

[Wisper Bikes]

We hardly ever need to fix motors. It's so rare now to have a problem we simply swap out for a new one whilst under warranty. We keep stock of planetary gears etc in Kent for very old and heavily used motors just in case.
Bikes and components made in China are getting better and better, as long as people buy a trusted brand in the UK such as Kudos, Woosh or Wisper etc they need not be at all concerned.

All the best, David