New Q128 for Xmas.

It gets better and better. They've just increased the power of the Q128 and called it the Q128H like they did with the Q100H. There's so much choice of motors now that it's nearly impossible to decide.

bike conversion kit

My favourites in order of power:

Rear

Q100CST 15mph

MXUS MX04 CST 20+mph

Bafang 350w CST 19mph

Xofo 500w CST 19mph at 36V, 24mph at 48v

Bafang CST 500W 22mph+

Front

Q75 15mph

Q100 15mph

Q100H 20+ mph

Q128H 15 mph (not tried one yet)

Bafang BPM 350W

Bafang BPM 500w

Blimey that q100h front drive can really shift! : )

Especially if you throw it off a cliff or the Forth Road Bridge.

I've edited now, so they won't understand your comment.

Especially if you throw it off a cliff or the Forth Road Bridge.

 

I've edited now, so they won't understand your comment.

Boo.. No fun

Q100H 201 mph

There you go

Hi d8veh,

I jave been messing about, testing a 250w BBS01. Great kit. It's on an old 700C lady's bike as the test rig. I originally wanted to put it on either my old Moulton APB or the later TSR but the BBS01 gear case interfered with the suspension pivot bolt on both bikes. Disappointing!

So I've been toying with the idea of putting a small rear hub motor on one of these 20" wheeled Moultons. Which would you recommend please? I was rather keen on the Bafang Q100H because it seemed to be a compromise between 'fast' and 'slow' and it's small and black (I want stealth!)

I can use either 36v or 48v batteries and my main aim would be to maintain at least 25km/h in pedal assist mod with maximum range and the occasional moderate hill climb. Both bikes are 7 and 8 speed derailleur. I would appreciate your advice.

Thanks,

Savvas.

Top speed = 15 x (RPM at nominal voltage)/201 x (wheel dia)/26 x (actual battery voltage)/(motor nominal voltage).

Choose your motor RPM and battery voltage wisely. I'd say that you need at least 328 rpm unless you're going away from nominal voltage.

The Q128 takes a free-wheel, which will limit your gears to 7 speed, and you will need to get a DNP one from Cyclezee with 11T top gear if you don't want to pedal like a 7 year old on his toy BMX.

The Q128 is not particularly small, neither is it particularly powerful at 36v unless they changed something in the "H" version. It is very smooth and quiet though. Increasing the current doesn't add much power compared with the effect on other motors.

A 48v battery is probably going to be heavy too.

I think that battery installation is going to be your main problem. I'd get that sorted in your head first before worrying about the motor. What type of attery can you fit? What voltage? Can you manage lipos?