Recommend me a BB drive

For around 35-40 mph, good acceleration/torque.

How much power can I run through the chain on a bicycle ?

I would like to try some other motors than hubs because I don't have the tools/space for a proper work area and making torque arms is a pain.

I want to goto a proper full suspension bike maybe a downhill and a bb drive would be best.

I should add that I want 30-40 mph with 12S LiPo.

There are several people working on a drive similar to the GNG-gen2 BB-drive, but using the MAC as the motor. The GNG-gen2 is a pretty trouble-free drive system, but it seems to be limited to about 750W continuous as far as heat-shedding is concerned (temporary peaks can be higher, of course). This summer, there should be several selections available that can put out 1500W continuous, at which point the freewheel will become the weakest link. $18 from bikemotive for the often used ACS-Crossfire.

Whether or not this type of drive will work for you and others with similar goals remains to be seen.

Yep I saw the mac conversion crossbreak did, but there are no kits yet.

The GNG V2 is a bit underpowered for me. I need something that can do 35-40 mph with 12S.

I don't really care about using the bike chain and gears, all I want is something geared right that won't burn at high power especially climbing the hills.

The GNG kits are fine for crawling up steep hills but I want to climb a lot faster than they can.

The power limit on a BB-drive (IMHO) is the freewheel at the crank. The White-Industries ENO is the absolute strongest FW when used on an in-line chainline. The two chainrings required by common BB-drives apply some twisting loads to the FW, and field reports seem to suggest that the ACS-Crossfire might actually last longer than the ENO in that particular application.

...40 mph with 12S LiPo...I want is something geared right...for crawling up steep hills...

Click to expand...

It is starting to sound like you might be best served by a non-hub drive that powers the left side of the rear wheel. I would suggest something similar to Lukes Death-Bike (pictured below), but with DH forks and rear suspension.

If you use a single-speed chain tensioner, It may be possible to run two sprockets on the motor-shaft, allowing you to stop and hand-shift the chain from a 40-MPH street cog to a smaller off-road sprocket. It's just a thought because I have never done that before, though I find the idea to be intriguing...

Either way, I will be interested to see what you decide on.

Yep a setup like Luke's would be more like it, though the power wouldn't have to be so brutal, Luke is Crazy!

It would have to fit on a normal bike frame, and be pretty much plug and play as I don't have the space for working or much tools.

If I could get around 2KW through the normal bike gears and do 35-40 I'd be pretty happy.

"John in CR" is selling three motor sizes that were originally made to be hub-motors for a 48V scooter. High efficiency than common E-bike hubmotors because they have thinner laminations made from a higher-silicon steel:

Price__diameter X width of stator__Kv is RPMs per volt

$285, 150mm X 50mm (5.9 X 2.0-inches) 17-Kv 3240W/4-HP at 72V X 45A, the shell is roughly 6.8-inches diameter, and 4.5-inches wide.
http://endless-sphere.com/forums/viewtopic.php?f=31&t=40859

$389, 163mm X 56mm (6.4 X 2.2-inches) 17-Kv
http://endless-sphere.com/forums/viewtopic.php?f=31&t=47607
http://endless-sphere.com/forums/viewtopic.php?f=6&t=42531

$539, 175mm X 60mm (6.9 X 2.4-inches) 7,000W / 9-HP
http://endless-sphere.com/forums/viewtopic.php?f=31&t=46898
http://endless-sphere.com/forums/viewtopic.php?f=3&t=41604

Yep I'll probably have to get a new hub in a 20" wheel, but to be honest I need a new frame for a hub as the one I have can't take much more power.

To be honest I'd like something ready built like the bomber but that is way too expensive!

I just don't have the place to work on bikes!