Small front motor Q85 / Q75?

[Blunderbuss]

I am working out the components to do a build for a light rider (45kg) who wants the simplest of setups; only going out at weekends, on tarmac when the weather is okay and not more than a couple of hours at a time.

With that spec list I was thinking of a small front hub, I will build the battery so no issues there. Having done a bit of googling a 1.6KG Q' motor looks a possible fit. BMS has a number of versions (Q70, 75 and 85) and I could get the 201rpm versions and run them at 48V.

Does anyone run any of these and have any experience - thanks.

 

[Nealh]

48v may be a little too much for these lightweight unless you use a max 12a rated controller, safer with 36v 15a.
Lightest Q is 1.2kg so 48v will kill it quite quickly.

 

[Blunderbuss]

I tend to get fixated with 48v!, I want to be as reliable as possible so 36v will be fine. Thanks

 

[theabsurdman]

Looking for the lightest possible front hub motor for a sub-11Kg 20" folder, I got excited by the Q75 at 1.2Kg only to hear that it doesn't support a disc brake, is this correct? And if so, is there any hack to enable a disc to be mounted? By drilling holes or some other means? Why would they not make a disc version?

I might have to bite the bullet and settle for the 2.1 Kg Q100. Or is there something else I should be considering <2Kg?

I've read about the The 1.4kg 2-speed Xiongda YTW-06 but thinking it night be difficult to source.

 

[Woosh]

I got excited by the Q75 at 1.2Kg only to hear that it doesn't support a disc brake, is this correct?

the Q75 fits 3" dropout, there is very little room left on the axle, even for anti-rotation washers so the anti-rotation device is incorporated into the axle.
On small folders, if you want disc brakes, go for a rear hub motor.
I have done that on my Rambletta.
https://wooshbikes.co.uk/?rambletta

Another way of making a light folder is to convert a Brompton with the Q75 and a Bosch tool battery.

 

[Nealh]

This one is disc compatible.
1.44kg AKM-75SX 36V250W EBike Front Driving Hub Motor 20/28/32/36 holes [AKM-75SX 36V250W Front Motor] - $99.00 : Zen Cart!, The Art of E-commerce (topbikekit.com)