Bafang BBS02 Top Speed?

makuch

1 µW
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Mar 17, 2015
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Hi guys, just to give you a little background I'm fairly knowledgeable with ebikes, but mainly with hub drives. I'd like to convert my Northrock XC-6 to electric, but I'd like to do it with a mid-drive and make it go over 35mph. I'm not sure if this is beyond the limits of the BBS02 750W motor? If it is, what would be my best option to get over 35mph without using a hub motor?

Thanks!
 
It doesn't seem to be impossible. A guy has done 50+ mph top speed. But it was with a road bike and he modified the bafang 750W.
Check him out. https://www.youtube.com/watch?v=OctRu79TcQ8
 
With the right gearing and you adding in about 300 watts of pedaling, you can definitely hit 35 mph. My bbs02 tops out at 32 but could definitely make it with higher gearing.
 
IzzyMandelbaum said:
It doesn't seem to be impossible. A guy has done 50+ mph top speed. But it was with a road bike and he modified the bafang 750W.
Check him out. https://www.youtube.com/watch?v=OctRu79TcQ8

Assuming his road bike was fully unfared(I saw none in the video), this modified motor had to be making like 5 kW to get him to that speed on flat ground. I wonder how he did that... A rider on a road bike has as much aerodynamic drag as an efficiently-designed small car.
 
The Toecutter said:
IzzyMandelbaum said:
It doesn't seem to be impossible. A guy has done 50+ mph top speed. But it was with a road bike and he modified the bafang 750W.
Check him out. https://www.youtube.com/watch?v=OctRu79TcQ8

Assuming his road bike was fully unfared(I saw none in the video), this modified motor had to be making like 5 kW to get him to that speed on flat ground. I wonder how he did that... A rider on a road bike has as much aerodynamic drag as an efficiently-designed small car.

I've been watching his vids, but his description has:

"Motor:
•Bafang 8fun BBS02 750w 48v (1470watts at 58.8v)
•Custom controller settings with maximum throttle enabled
•52 tooth chainring (85.5km/h top speed)
•155 RPM at 58.8v (factory settings 120 RPM maximum)

Battery:
•Homemade 14s 5p 58.8v 14.5Ah battery pack capacity
•1,5 hours safe fast charge (6A 350w charger)
•70x NCR18650PF Panasonic High Current cells bare pack for better cooling
•No BMS for 100% charge & 100% performance!!
•Range: +/-26km in the city / 36km continuous full throttle with few stops

Throttle / Brake Sensor:
•Left thumb throttle adapted to road bike handlebar (almost invisible)
•Magnetic sensor for mechanical rear brakes

Dashboard:
•2x 15 watts LED headlights (two modes: normal or high bean)
•Red LED Voltmeter for battery performance monitoring

Bicycle:
•Trek Road Bike"

All his videos, you can see him keeping with moving traffic and over taking. But it's hard to determine the speed of the traffic. But the pace at which he passes regular cyclists. You can tell he's going pretty fast.
 
You're not going to hit 35mph unless you're going down a hill.

For your reference, here's my set up with the BBS02 Samsung 25R 48V on a Giant Iguana Disc (26 inch wheels) with 48T and 11T and me weighing about 150 pounds, 28-30mph is about max unless I'm pedaling hard.
 
IzzyMandelbaum said:
The Toecutter said:
IzzyMandelbaum said:
It doesn't seem to be impossible. A guy has done 50+ mph top speed. But it was with a road bike and he modified the bafang 750W.
Check him out. https://www.youtube.com/watch?v=OctRu79TcQ8

Assuming his road bike was fully unfared(I saw none in the video), this modified motor had to be making like 5 kW to get him to that speed on flat ground. I wonder how he did that... A rider on a road bike has as much aerodynamic drag as an efficiently-designed small car.

I've been watching his vids, but his description has:

"Motor:
•Bafang 8fun BBS02 750w 48v (1470watts at 58.8v)
•Custom controller settings with maximum throttle enabled
•52 tooth chainring (85.5km/h top speed)
•155 RPM at 58.8v (factory settings 120 RPM maximum)

Battery:
•Homemade 14s 5p 58.8v 14.5Ah battery pack capacity
•1,5 hours safe fast charge (6A 350w charger)
•70x NCR18650PF Panasonic High Current cells bare pack for better cooling
•No BMS for 100% charge & 100% performance!!
•Range: +/-26km in the city / 36km continuous full throttle with few stops

Throttle / Brake Sensor:
•Left thumb throttle adapted to road bike handlebar (almost invisible)
•Magnetic sensor for mechanical rear brakes

Dashboard:
•2x 15 watts LED headlights (two modes: normal or high bean)
•Red LED Voltmeter for battery performance monitoring

Bicycle:
•Trek Road Bike"

All his videos, you can see him keeping with moving traffic and over taking. But it's hard to determine the speed of the traffic. But the pace at which he passes regular cyclists. You can tell he's going pretty fast.

Even with aerobars(which I don't see in the video) and the most aerodynamic DF frame available, 1470W is still not going to get a road bike to 50 mph. There's simply too much drag. With aerobars, he might get a Cd of 0.6 at the lowest and a frontal area of 4.5 sq ft or so. Even with a 0.0045 Crr on the most efficient tires available, he's still only going to do like 45 mph on 1,470W, using 0.6 Cd and 4.5 sq ft. Riding on the hoods as he is seen doing yields something like 1.0 Cd, 5 sq ft area, which would get him to 36-37 mph. To do his claimed 55 mph in the video with an assumed Cd of 1.0 and a 5 sq ft area, 5 kW is needed...

Either he's lying about his speed, and/or he's making at least twice as much power from this motor as he claims, and/or he's pedaling with like 1.5+ kW in addition to this motor's claimed 1470W and/or he has had one hell of a tailwind or a decent downward slope.

55 mph on a road bike is going to require as much power as a small motorcycle of the same speed, absent any significant concessions to reducing drag.


makuch, given that a mountain bike had similar drag to a road bike, in short, you can do MORE than 35 mph with a stock BBSO2, if you have the right gearing and are strong enough to pedal for it when using the motor. I can do 32 mph on a Raleigh Technium with no electric motor at all riding with my hands on top of the bars, for a few seconds at least. If I had an extra kW to add to that pedaling, something close to 40 mph could be in grasp... and I'm a strong rider.

If you're using the motor-only, 30 mph or so is about all you're going to get with a stock BBSO2, unless you build a faring, or better yet, ditch the mountain bike and build a streamlined velomobile out of a recumbent. A faring for an upright bicycle is typically not a practical endeavor though, especially if you're going to be pedaling it, as lack of rider cooling, safety, and vulnerability to crosswinds all will become significant problems(I've tried it once). Then, at 30+ mph speeds, you have to worry about road debris and potholes sending you airborne. I've been airborne on my Raleigh before, and it's very dangerous and not my idea of fun. Imagine if your front wheel hits a pothole at 35 mph and turns into a taco... I got lucky!
 
On these lines... I just picked up a new to me 1999 Gary Fisher Tassajarra that had been sitting in a storeroom for about a decade. Got the dried out grease in the shifters working and now ready to order up a BBS02 from Lunacycle... what has been stopping me is choosing a chain ring. Stock on the bike is a 42 tooth big chain ring and I am going to be using this almost exclusively on the streets as a commuter.

Looking for feedback in a semi hilly area... wanting to hang with 30-35mph traffic that is stop light to stop light, should I go with the 46, 48 or 52 tooth option? I don't know what the happy rpm is for the motor (at the crank). With this kit I'll still have 8 cogs to choose from in the rear, looks like the low gear is 30 tooth... 26" rims.

Any input?
 
I have problem fitting 52T because it would grind against the chainstay, thus difficult to put road cranks on mountain bike frames. But 48T front -11T rear with 26 inch wheel, you will not hit 35mph without help from gravity. And I strongly recommend good fork and disc brake. You'll end upgrading anyway since you wouldn't want to die.
If you have front 52T and rear 11T with 700c or 29er, then possibly you can gain a few more mph.
Or wait for the BBSHD, which should be due very soon.
 
Have a read of the mid drives section of the wiki on Bafang units. There's more to choosing a chainring than just size for speed - offset may also matter depending on the width of your BB.
 
I have a Bafang BBS02 mounted on a Downtube 20" folding bike. 44T chainring because I'm in seriously hilly area. In Top gear, I hit 28mph. But I can do 10mph on 20 degree gradient hill in 2nd gear pulling 16amps.
 
I can do 39mph gps verified on a crappy $300 mountain bike with 2.2" knobby tires at 30psi with a 52T ring and a 58v battery on a slight 3 percent downgrade at 210lbs.

It wouldn't surprise me if Bruno (who is very light and small) can get close to 50 on a roadbike with a slight downgrade. My roadbike is MUCH faster than all my other bikes. I doubt he is really getting 54mph though, that seems like an exaggeration.

He should do some gps verifications.
 
It is impossible to go 85kmh with 1500W electric input. There is effectivity of motor 85% and also reduced current in high rpm!
 
I hit 55 km/h (~35mph) on flat with knoby tires (26" kenda navegal) with 46T front and 11T rear chain. Motor max out is 73km/h when i lift rear whell. It goes 70 downhill :mrgreen:
 
To be perfectly honest.. the bbso2 will go around 30MPH. That's with 42T lekkie bling ring and 11-36T cassette in the back. You can opt to go with bigger chain ring in the front like 52T or even 58T but it'll suck at climbing and will be unstable for your chain. 30MPH is plenty enough for a bike trust me on that. If you're not satisfied than probably go with the BBSHD version wich will take you around 5~10miles faster again depending on your weight and bike and gears,how heavy it is definitely plays a role... I'm around 200lbs and 6'3" so i'm a big guy if you're lighter you can go faster. But this is just my experience with the bbso2. I love it. It's still going strong after 2 years and 3.5K miles on the bike. Was thinking about upgrading to the HD but that's $600 and that's a chunk of cash for me to spend just to be able to go a little bit faster...
 
intramorph said:
To be perfectly honest.. the bbso2 will go around 30MPH. That's with 42T lekkie bling ring and 11-36T cassette in the back. You can opt to go with bigger chain ring in the front like 52T or even 58T but it'll suck at climbing and will be unstable for your chain. 30MPH is plenty enough for a bike trust me on that. If you're not satisfied than probably go with the BBSHD version wich will take you around 5~10miles faster again depending on your weight and bike and gears,how heavy it is definitely plays a role... I'm around 200lbs and 6'3" so i'm a big guy if you're lighter you can go faster. But this is just my experience with the bbso2. I love it. It's still going strong after 2 years and 3.5K miles on the bike. Was thinking about upgrading to the HD but that's $600 and that's a chunk of cash for me to spend just to be able to go a little bit faster...

This is the setup I've ordered.. was wondering exactly this. What's your wheel size, by the way?
 
I have gone 42 mph With a BBS02 46 tooth chain ring and 11 tooth cog on a trek 8900 downhill hard tail from 1998 , And in Chicago which is super flat. Also consider I was running a winter steel studded tire that had MASSIVE tire rub that scratched the frock out of frame. Since I’m a teenager and dumb I had the cable to taught and it over heated about two weeks ago after about 900 miles of use so not knocking it at all I installed it poorly and learned. My new piece comes in a few days and in the meantime I got some light trail commuter tires that are about 12% more efficient according to strava. And I’m putting a much needed new chain on it. This summer I plan work since I’m a student rn, and I’m gonna put a new chain ring on the front 52 tooth leckie, and I’m gonna buy a new front suspension(one problem is finding one that works on this old bike)
 
My bbs02b fitted to a marin mount vision 2 enduro with 2.4 flow rumba sticky tyres used to cruse along off road fire rd trails / canal toepaths at 24 mph no probs withe a 42t ring.I had the lunacycles firmware program installed sorry can't remember what it was called. The best for progressive cadence assist was still abit of a run away train so iv got a tongsheng tsdz2b to try out now.
 
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