do freewheel direct drive hubs exist?

[ipub]

Hey, I'm a bit confused by this. I'm researching my first hub purchase for a commuter bike and was thinking I'd need a geared hub for the freewheel aspect but I've just been told by an ebay seller that their direct drive has a freewheel. Is that right ?

http://www.ebay.co.uk/itm/390503382516? ... 26_rdc%3D1

Im still weighing up my options at the moment but I'm planning on converting my existing hardtail mtb with a rear rack mounted 20ah battery with a front hub for balance. I've heard that direct drives in the front can seize up causing the rider to go over the handle bars so I could do with some opinion on these ebay motors.

 

[miuan]

never heard of one..
you possible made the usual mistake of asking a chinese vendor question with a yes/no answer, in which case you always receive a yes answer. they probably meant the hub has a threaded freewheel mount, but it sure has no internal freewheel and the motor WILL cog a much as any other similar DD motor.

 

[dogman dan]

Typically a planetary gear motor has an internal freewheel in addition to the external one for the derailur gear cluster.

Why the second freewheel? Because if you don't have power to the motor, a dd motor does resist some. It's not much resistance, but if you want to use the motor only infrequently and just pedal normally most of the ride, then you want the second freewheel.

Personally, if I'm trying to save battery by just pedaling, I just give a dd motor a tiny trickle of throttle and eliminate the motor drag that way. 50-100w will take only 50-100wh from your battery in a full hour of pedaling. And since I tend to carry about 700wh of battery, that tiny bit of power used to eliminate the drag is affordable.

Breakdowns, well, then you might wish you had the freewheel. But for me most breakdonws aren't a motor problem, it's a flat tire generally.

 

[dogman dan]

As to the motor locking up and throwing you. Yes it can happen, but it's pretty rare. Much much more likely to happen is another type of problem with front hubs.

All hub motors have to be mounted very carefully, sometimes adding special washers not provided by the seller, and using some type of torque controll device. Torque arms up front, or torque plates you often custom make yourself in back, will greatly help to secure the motor axle from rotating. In front hubs in particular, a mis fit wheel might leave the bike completely, or just jump out of the dropouts and jam. Either way, you go over the bars. Often this happens with alloy shock forks that crack easily with a hubmotor.

This issue with a poorly fitted hubmotor twisting out of the dropouts happens with both gearmotors and dd motors.

Sometimes a low enough power motor can be used with no torque arms, but it's not very advisable, especially in front.

You can still go over the bars on any bike real easy. I did it by fumbling a water bottle into the forks. Broke both collarbones and 5 years later I still know when storms are coming when the bones ache like mad. I still go over the bars riding dirt trails fairly often just by cranking a turn too sharp.

 

[ipub]

man, that sounds pretty painful! ouch!

I'm aware of the torque arms and will be using them on my own steel forks I guess I'm just looking to see if a direct drive motor is going to be a pain or not.

front or back.. front or back. A question I've asked in a number of non bike related situations.

 

[spinningmagnets]

The link you provided lists regen, so it does not have a freewheel internally like the geared hubs. I'm sure he thought you were asking about the external gear-cluster...which I have read of some people referring to as a freewheel.