Are there any good free running motors that support disk brakes?

[Deleted member 4366]

We've been through all this before. People can just watch my Youtube vide and draw their own conclusions.
YouTube - Bafang

 

[Caph]

I have a Bafang front hub fitted to my wife's bike. It used to have a Tongxin hub which are renown for their freewheeling abilities. I swapped it out for a Bafang after the tongxin motor shaft broke up, i think in November 2010.
The Bafang is nicely 'run in' now and freewheels as good as the Tongxin hub used to. I reckon it has around 250miles on it
Look at the video
YouTube - SDC12193

Curly, believe it or not I've been spending ages tonight trying to find out how good the freewheel capabilities are of the 8Fun Jewel qswxk as sold by Alien, and unless I'm mistaken that is the very same motor. I couldn't believe the good timing of your post!

Does it have the 6 rotor fittings for a disk brake on the other side by and chance? How do you find it in general?

The reason I'm looking is that I just got hold of a some Rock Shox Dart 3 forks because my Zoom forks have given up the ghost after I forgot to oil them during all the snow and ice and the springs got rusty and snapped. But I finally got down to measuring things tonight and realised that my current SB motor with disk rotor requires about 125mm between the forks, which puts me in the same boat as the original poster because the Dart 3's only have the standard 100mm width.

I love my 180W SB motor exactly because it has such a good freewheel - it's more like this. I just can't ride my Alien GS1 without power though because the drag makes it feel like I'm riding with the brakes on. But the freewheeling in your video is more like the Alien GS2. That makes it not as good as I'd hoped but not as bad as I'd feared. I reckon I could live with it.

Could you confirm it is the 8Fun QSWXK you have?

Cheers.

 

[mechaniker]

Hi caph,

the video from "wurly" show´s a Bafang "SWXK" with disk appliance

the video from "Kraeuterbutter.at" shows a Bafang SWXB (old modell) with 120mm wide.
The today Bafang SWXB is 100mm wide but Kraeutterbutter use the old modell.

regards
frank

 

[Pedalo]

Thanks again for all comments so far. All feedback is welcome.
I think I'll just have to try a Bafang for myself. It's not too much expense if it turms out not to be quite what I'm looking for.

To be honest I don't ride my bike particularly fast so if the resistance is mainly felt at, say, >20mph I think I'll be happy.

I might also look at the price of Ezee without the battery.

What are the pros/cons between the rear Bafang (SWXH I think) and the front (SWXK)? I know I need to try to get a type 2 SWXK and need to watch for fork compatibility as pointed out by Frank in another thread. Are there similar things to watch regarding the rear motor? Will they work with all cassette types?

Finally, I already have a spare motor controller suitable for a Tongxin brushless 260rpm motor. Would this also work on a Bafang (any rpm) or will I need to get a specific controller?

 

[flecc]

What are the pros/cons between the rear Bafang (SWXH I think) and the front (SWXK)? I know I need to try to get a type 2 SWXK and need to watch for fork compatibility as pointed out by Frank in another thread. Are there similar things to watch regarding the rear motor? Will they work with all cassette types?

Front drive has the advantage of two wheel traction, pedals driving rear and motor at front, useful in poor road conditions. It has the disadvantage of less comfortable ride due to the high unsprung weight. Suspension forks alleviate the effects of that to some extent. Traction can also be lost on poor or slippery surfaces with a powerful motor when pulling a trailer uphill.

Rear motors have the advantage of greater comfort and better trailer control. The disadvantages are poor weight distribution, much of the weight at the rear, and often gearing limitations. For example, no hub gears possible, and derailleurs limited to using freewheel sprocket clusters. These are much more limited in range than cassette systems and are weaker as well.
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[Pedalo]

Front drive has the advantage of two wheel traction, pedals driving rear and motor at front, useful in poor road conditions. It has the disadvantage of less comfortable ride due to the high unsprung weight. Suspension forks alleviate the effects of that to some extent. Traction can also be lost on poor or slippery surfaces with a powerful motor when pulling a trailer uphill.

Rear motors have the advantage of greater comfort and better trailer control. The disadvantages are poor weight distribution, much of the weight at the rear, and often gearing limitations. For example, no hub gears possible, and derailleurs limited to using freewheel sprocket clusters. These are much more limited in range than cassette systems and are weaker as well.
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Thanks Flecc, this is becoming clearer in my mind now. So if rear motors only support freewheel clusters and not cassettes, I think this means they will be less appropriate for bikes which already have, say, a 9 or 10 speed cassette fitted. In terms of gear indexing, are 7 or 8 speed freewheels compatible with 7 or 8 speed cassettes? By "weaker" do you mean the sprockets wear down quicker, or are they actually known to break?

 

[flecc]

In terms of gear indexing, are 7 or 8 speed freewheels compatible with 7 or 8 speed cassettes? By "weaker" do you mean the sprockets wear down quicker, or are they actually known to break?

I can't speak for 8 or more sprockets, but I've had no indexing problems doing a pick-a-mix of derailleur components on 5 to 7 sprocket freewheels. Cheap ones do run very coarsely though, more noise and transmission roughness of gear change and chain running.

As for weakness, the choice of freewheels is very limited and most of those available are very poor, soft materials which wear fast etc. Shimano make a cheap and not very cheerful limited "Cadet" range, but also the odd better ones which are very difficult to track down.

Theres also a fundamental flaw in the multi-sprocket freewheel bearings. Cheap ones have a single inboard bearing which is subject to lots of twisting force when the chain is on the outer sprockets, so they can break. Better ones like Shimano's HG50 do have twin bearings, but the outer bearing is still nowhere near the outer side due to the freewheel design. The core of the cassette is much better supported by it's bearings.

The cause of these differences is that motors use a 12 mm spindle which is too large for the cassette system which is for standard 10 mm bike spindles.

Edit: Member Jeremy posted this on freewheels recently:

"the two companies that made small sprocket 6 speed freewheels seem to to be Regina and Sunrace. Shimano are reputed to have made a very short production run of them, but these seem rarer than hens teeth. There is an extremely nasty (but not very cheap) 7 speed wide range freewheel available from the Chinese company DNP, but in my experience DNP make their stuff from material with all the structural properties of soft cheese, so I couldn't in all honesty recommend it."

All this said, freewheels do work on all the rear motor bikes on the market so are not to be ruled out entirely, especially since there's less pedalling strain necessary on e-bikes usually, due to the motor assistance.
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[Caph]

Hi caph,

the video from "wurly" show´s a Bafang "SWXK" with disk appliance

the video from "Kraeuterbutter.at" shows a Bafang SWXB (old modell) with 120mm wide.
The today Bafang SWXB is 100mm wide but Kraeutterbutter use the old modell.

regards
frank

Thanks Frank. I think I'll go along with Pedalo on this one and give the SWXK a shot.

 

[piotrmacheta]

Just to add to all the answers:
Front needs a 180mm disc to give enough room for the caliper - I found that there was nowhere near enough room with 160 and I tried Avid, Hope and Magura calipers. 180mm is easy to buy and fit and I bought an adapter that bolts betwen caliper and fork that changed the brake to fit. I also prefer the extra bite of the bigger disk.
I like front wheel drive and the benefits of keeping a hub or cassette on the rear. Also when picking the bike up in the middle the ballance is spot on.
Rear electric hub is a bit of a pain as the freewheels feel cheap and nasty compared to a cassette and they feel gritty and are noisy and difficult to get a good spread of gears. I ordered one from ebikes.ca as I wanted a 12-32 and it's already making funny bearing noises due to use in the wet.
When turning the wheel the ezee hub does come to rest in a few turns and indeed quicker than a normal wheel but it's not really noticable on the road. I one freewheeled down a steep hill and reached 40mph with it and then when I tried my normal wheel it was about the same.
It's true that the tyres will make the most difference. I once wondered why I couldn't reach a decent speed on my normal run to work and it was down to knobbly tyres at low pressure. Of course wind pays a big part too - I love the windy days as it's too easy!
Oh, in case you didn't pick up from the other post, you can just buy the wheel on its own as I did but it's about £250 - Onbike are brilliant and will advise you.

 

[Streethawk]

I've been thinking of putting a Golden Motor Magic Pie 1000w combined front hub motor and controller on my old Marin full suspension MTB, to create a real powerful off-road hill climber, keeping the big knobbly 2.5" tyres and such, with the battery on a seatpost rack to balance out the weight. With the internal controller in the Magic Pie this should be a relatively neat solution.

 

[John L]

Just to add to all the answers:
Front needs a 180mm disc to give enough room for the caliper - I found that there was nowhere near enough room with 160 and I tried Avid, Hope and Magura calipers. 180mm is easy to buy and fit and I bought an adapter that bolts betwen caliper and fork that changed the brake to fit. I also prefer the extra bite of the bigger disk.

Its funny how threads start and then it rings bells for other people! I only became aware yesterday that my 8fun SWXK was capable of taking a 6 bolt rotor. I remember reading that the motor was suitable for disc brakes but as I had never really looked at this type of brake before it didn't mean much to me.

I was especially lucky that when I replaced the original forks with Suntour NEX 4110 suspension forks that it could take both v-brakes and disc brakes I was only concerned at the time that the new forks could take v-brakes.

It would appear from Piotrmacheta's comment that a 180mm rotor would be best suited to the motor and as it happens the forks seem to be intended for the same size rotor. So happy days

With regard to the front hub motor - I have found that after the 1200 miles I've done, the wheel definitely freewheels better than when I first bought the kit. I'm sure its not as free as a normal wheel but it feels pretty good.

John

 

[jbond]

I see the new motor used in the Storkk has a cassette gear cluster. I wonder if that's where we're going and rear hub motors will start coming with these.

Right now, it's all a bit of a pain. The Shimano 14t-28t and 14t-34t are cheap and easy to get hold of. IMHO, they work well enough if you oil them occasionally. And 48t-14t-26" is fine at 15mph and ok at 20mph. It would have been nice if the 11t 7 speeds worked well as it's probably a bit cheaper than fitting cranks with a bigger front chain ring.

Rear hubs look "right" to me but perhaps I'm mistaken. Front hubs have their own problems as well such as avoiding alloy forks and the greater need for torque arms.

 

[flecc]

I see the new motor used in the Storkk has a cassette gear cluster. I wonder if that's where we're going and rear hub motors will start coming with these.

Now that we have side plate cable entries appearing as on the latest SB motors, instead of spindle hole entry, it may be that a return to 10 mm spindles is possible, permitting cassettes.

However, that Storck motor is direct drive so narrow, which makes it easier to incorporate a 10 mm spindle. Internally geared motors like the SB range are of necessity much wider, meaning a longer length of unsupported spindle.
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