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Me 1st !

I started looking and was considering a factory ebike; the RadMini. A perfect Tender for the Spark EV.

Then I stumbled upon a brand new thing: ebike Mid-drives. You remove the existing crank/chain ring assembly and add these kits!
There are lots of power levels and two main kit makers.

This one has torque sensing that multiplies the power you are applying to the pedals with 5 levels of assist: http://auto-ebike.com/index.php?main_page=product_info&cPath=25_1&products_id=1802
I can keep my lightweight disc brake wheels and 9-spd rear drive train on my full suspension Mtb nike. Hub wheels are big, heavy and visible.
This is stealthy and the added weight is low and in the center!

To get a decent battery pack/charger from a known manufacture (tricky) you have to pay much more.
 
Very interesting indeed, I dd not know Bafang had a Kit motor with Torque sensing.
Sounds pretty nice and easy to install!

One confusion, is that in most places I see it labeled 350W 36V battery, but the seller link you mentioned 500W and 48V battery.

Do you know if it is a newer version, or just the 350W model boosted by using a 48V battery instead of a 36V, Or just Chinese website "marketing" :)
Also do you know the peak power of the motor?

It also seems like there is only a torque sensing, and no cadence or speed sensing into the mix.
Torque sensor alone can lack smoothness, as when you are not applying pressure the motor would cutoff, causing an uneven assist on cruising speed.
Will look for reviews on the subject..
 
scrambler said:
Very interesting indeed, I dd not know Bafang had a Kit motor with Torque sensing.
Sounds pretty nice and easy to install!

One confusion, is that in most places I see it labeled 350W 36V battery, but the seller link you mentioned 500W and 48V battery.

Do you know if it is a newer version, or just the 350W model boosted by using a 48V battery instead of a 36V, Or just Chinese website "marketing" :)
Also do you know the peak power of the motor?

It also seems like there is only a torque sensing, and no cadence or speed sensing into the mix.
Torque sensor alone can lack smoothness, as when you are not applying pressure the motor would cutoff, causing an uneven assist on cruising speed.
Will look for reviews on the subject..
Bafang only recently is claiming torque sensing on a new mid-drive that only goes in the new specific ebike frames. Not for the retro fit market.
The Tongsheng TSDZ2 has been around a while with the 48V / 500 Watt version.
It has a speed sensor to limit, but also display your speed.
Since it senses torque, it only applies power when you are pedaling. Just like the rider does ! ;) It has 5 levels of assist. Hint: there is an optional throttle lever.
From what I read it is an advancement compared to the simple PAS that the Bafang system uses.
 
I built a rear hub bike using a magic pie 3 a couple years ago. Haven't got much use out of it. I bought it to save on gas, but then my car died and I bought the Spark.

They are pretty fun, and I can get pretty decent speed without pedaling (except for takeoff).
 
67goat said:
.... pretty decent speed without pedaling (except for takeoff).
That's the deal with old style hub motors. They don't have any gearing at all, which is a very limited RPM range.
There are now geared hub motors which help with slow speed power.

Mid-drives have gear reduction to spin the motor fast and you use the existing bike gear train to keep it in a decent range by using the same cadence as you'd normally pedal.

Supposedly the torque sensing is quick responding so if you are riding a mtn bike in twisty, rocky sections it is seamless the way it feels.
Except you are so much more powerful on the uphills !
 
Lightweight, 700c, no shocks, all flat ground. Pretty easy to get up to 10 mph on pedal power, motor takes care of it from there. It can do okay on takeoff (1000w), but it is slower than putting in a little effort. Since I didn't pedal any other time, it didn't bug me much.
 
I have seen the future! :mrgreen:

I test rode a Raleigh ebike with Shimano Mid-drive, 8-spd internal hub and a down tube mounted battery pack.
I don't know the power of the motor or battery.
There are identical switches near each grip. A + and - switch and black switch above those.
The left side selects 4 'Assist levels'.
The right side shifts the 8 gears in the rear hub.

But,,, I accidentally pressed the right black button on the right side and it went into 'Auto' shifting!
It acts like an automatic 8spd transmission. It shifts up and down to keep you at a good cadence. It up shifts before you get to a high cadence. Too soon for me but amazing !!

Manual shifting makes it stay in what ever gear you select.

All of this info is displayed on the small center mounted display.

I was riding up 4 level parking garage ramps like Superman!!

It's a $2700 bike, so I'm out.
But I know what Torque Assist feels like now!

The one negative: there is an almost 1 second delay on cutting the motor power when you stop pedaling. :eek: I wouldn't like that on the single track trails. :(
 
Automatic shifting is another great advancement.
The ultimate solution in that department, is the Nuvinci Continuously Variable Transmission with the Harmony automatic shifting Hub interface and controler.
http://www.nuvincicycling.com/en/products/harmony.html

The Nuvinci Continuously Variable Transmission (N380) gets rid of gears by allowing you to change the gear ratio in a continuous fashion (no steps).
The Harmony interface does the same as what you described, which is to adjust the ratio automatically, based on the pedal cadence you have selected.

Once you select the pedal cadence, it will vary the gear ratio to maintain that cadence, and because there are no steps, it is a totally smooth and seamless process.

The Harmony allows you to select either mode. You decide to continuously change the gear ratio yourself, or you can adjust a cadence and let the hub interface ajust the ratio automatically.

For me, the ultimate Ebike combination for urban and light trail is
Integrated Torque + Speed + Cadence sensing, for the most intuitive pedal assist you can get
Nuvinci Harmony, to get rid of gears and derailleur once and for all.
Gates Carbon belt drive, for no maintenance clean drive.
1000W of power

For agressive off road riding, an internal geared hub is probably better with that kind of power.
 
scrambler said:
... the Harmony automatic shifting Hub interface and controler.

..The Harmony interface does the same as what you described, which is to adjust the ratio automatically, based on the pedal cadence you have selected.

...For agressive off road riding, an internal geared hub is probably better with that kind of power.
But at 5.4 lbs for just this CVT hub (which consumes power by itself) and then add the mid-drive and battery pack.... I don't know...

I think I'll stick with my lightweight wheels and conventional 9-spd derailleur set up. As soon as something breaks, SRAM now has an 8-spd line of ebike specific drive train components.

My bike will be heavier with the mid-drive and battery pack but that will be the only weight added to this high-end Mtn bike, and the weight will be low and centered, not unsprung in the rear wheel.
All that will change when I ride is,, I have more power !!!! And I can select the amount, from 'Good Day' up to 'Superman'. Oh, and I don't have a front derailleur to mess with.
 
For and urban/ light trail bike, if you have 1000W of power assist, I think the benefits outweigh (no pun intended) the downside.

If you want a mountain bike for agressive off road riding, then I can see an IGH being more appropriate.

But I definitely dont want any derailleur on my Ebike :)
 
Now that they have automatic IGHs, I could see somebody with the time and inclination to build a hub motor around something like that. No derailleur, no manual shifting....

Put that on the rear of a bike with a second hub motor up front (saw a project where a guy had an AWD hub bike where both used the same controller, but were speed independent - building custom controllers with custom software is beyond me though)....

I would take that over a mid drive anything. Of course, my original build was based off price mainly.
 
67goat said:
saw a project where a guy had an AWD hub bike where both used the same controller, but were speed independent -.

The Adaptto controller can handle synchronized 2 wheel drive configurations
http://adaptto.com/Products/Controllers/
 
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