BBSHD: I'm skeptical

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flat tire   1 MW

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BBSHD: I'm skeptical

Post by flat tire » Apr 20 2017 2:40am

OK my background is a Leaf 1500 rear hub on 5kW sinewave thinking about picking up a BBSHD from Luna for my Orange downhill mtb. Bike will be optimized for off road but will spend plenty of time on road too. I used to cruise at 35-50 mph on the Leaf and would prefer to do the same on the BBS. I weigh 130 am 6' tall but optimize my body position so I am not the most energy inefficient rider. This motor is pretty good as it will power wheelie like crazy from a stop and go to 50+ all in one gear.

Could I possibly be happy with the BBSHD? Should I bother hooking it to an external controller? It seems like the stock controller is a huge bottleneck. If this is my plan should I just forget about the BBSHD altogether?

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Chalo   100 GW

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Re: BBSHD: I'm skeptical

Post by Chalo » Apr 20 2017 3:16am

The BBSHD is rated 1kW with proven ability to tolerate 1500W. Bicycle drivetrains are engineered for 1 human power-- about 500W-- with proven ability to tolerate up to 3kW or so for very short occasional bursts.

My favorite speed and power calculator suggests you'll need at least 5kW to maintain 50mph on flat ground. So you're asking whether it's a good idea to use a motor at 5 times its rated power and bicycle gears at 10 times​ their rated power.

If you don't already know the answer to that question, I expect you'll learn it very quickly.

Also, please get licensed and insured and stay off of bicycle facilities.
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Wheazel   10 kW

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Re: BBSHD: I'm skeptical

Post by Wheazel » Apr 20 2017 5:04am

Should you ditch the bbshd idea?
Probably

Also what Chalo said.

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Ykick   100 GW

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Re: BBSHD: I'm skeptical

Post by Ykick » Apr 20 2017 6:37am

Agree with last couple posts. I wouldn't push a BBSHD in a conventional bike over 30MPH for any length of time and expect rock solid reliability.
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

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r3volved   100 kW

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Re: BBSHD: I'm skeptical

Post by r3volved » Apr 20 2017 12:13pm

Also worth noting that 1500W will eat your smallest two sprockets in your cassette pretty quickly...

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Re: BBSHD: I'm skeptical

Post by flat tire » Apr 20 2017 12:42pm

The main purpose of this mid drive bike is to ride trails and off road so I can live with a reduced cruise speed. And what's with the attitude? Fast ebikes are awesome and commuting at high speed doesn't mean you have to ride like an ass. I'm very friendly and respectful to others with my riding and only generate positive interactions, including when taking the ride to a bike park.

Now, I understand there are issues running high power thru bike chains for when I modify the BBS. Let's say I put the bike on a much higher voltage with the external controller. Will this not reduce my chain stress? Will the increased chain speed create its own issues? Anyway I'll probably end up ordering the BBS in the next few days unless you all convince me otherwise.

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Re: BBSHD: I'm skeptical

Post by PRW » Apr 20 2017 12:51pm

I previously posted about a ride I did with my wife recently - me on a 6kw+ Phasor (Mxus 3k), my wife on a BBSHD on 52v, 30A. When the trail was open and clear, all good; but after about 90 minutes on tighter, slow steep trails, Mxus was overheating (thermal cutoff); the BBSHD wasn't even warm. So, horses for courses... and I will be getting a BBSHD to put on a Norco Atomik at some stage, for me!

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Re: BBSHD: I'm skeptical

Post by flat tire » Apr 20 2017 1:30pm

Also, there isn't really any elevation where I live so one ratio and a removed derailleur, plus tons of voltage to the motor running a big wheel in the back...you could pump TONS of power thru the bike chain by spinning it really fast!! I guess that'll be the plan I'll try the setup as intended from the factory for a week or two first though.

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Re: BBSHD: I'm skeptical

Post by fechter » Apr 20 2017 1:34pm

I have both a BBSHD and a 2.5kW dd hub motor bike. The hub motor is great for going fast on pavement but overheats quickly when climbing or going slow on trails. The BBSHD has a slower top speed, but is far superior for steep trails. Stuff that would put my hub motor windings to 150C makes the BBSHD barely warm.
"One test is worth a thousand opinions"

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Rassy   10 MW

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Re: BBSHD: I'm skeptical

Post by Rassy » Apr 20 2017 1:46pm

so one ratio and a removed derailleur
The main reason the mid drives were developed, and specifically the crank drives, was to allow the use of your gearing. Otherwise, they are more expensive, more prone to failure, and harder on the bike components. I love my BBS02s because they let me select the appropriate gear for either going up hills or riding on the flat.

But you should do what you want to do, that's the best way to learn what works for you. Please keep posting here to let us know how it all works out.
-Rassy-
One Tadpole Trike equipped with a Bafang BBS02
https://endless-sphere.com/forums/viewt ... 28&t=69419
One Delta Trike equipped with a Bafang BBS02
https://endless-sphere.com/forums/viewt ... 0#p1291260

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Re: BBSHD: I'm skeptical

Post by flat tire » Apr 20 2017 1:53pm

A single ratio will be fine here it's very flat and the only climbs are jumps. I keep up enough momentum on the trails to not overheat my Leaf at 10 -20 mph, don't need much power to sustain that so even though the powertrain is very inefficient at that speed the total wasted energy / heat is low enough to dissipate easily. Also I want to take this bike to the MX track.
Rassy wrote: The main reason the mid drives were developed
Ha. As far as I'm concerned they were developed for the awesome handling due to mass centralization and vastly reduced unsprung mass over a hub motor. I'm considering a BBS because it's a zero effort bolt on solution that seems like it might offer decent power potential with cooling.

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spinningmagnets   100 GW

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Re: BBSHD: I'm skeptical

Post by spinningmagnets » Apr 20 2017 1:57pm

I agree completely with the statements Fechter just made in the post above. I have recently seen several BBSHD owners running an external controller, in order to run as much as 50A, or 72V, but...not both.

Using 48V / 52V and then raising the amps to 50A means you might be able to use a battery you already have (if it's capable of 50A without getting hot). The mechanical portion seems to be holding up to the warmth of 50A.

As to using 72V X 30A, the drive runs cooler than when using 52V X 50A. However a 72V battery can be difficult to source in the size and shape you might prefer. Not to mention being somewhat pricey. Although a 72V controller with 6 FETs that can handle 35A peaks is small and affordable.

So...either way, the people using 2500W are likely experiencing rapid chain and sprocket wear, and possibly even the clutch and plastic primary gear inside the BBSHD...

I plan to increase my power to 2000W by raising the amps to 40A (@ 52V), and I am sure that 2000W will be fine for me, In view of my current satisfaction level when using the stock 1500W.

Regardless of which way you'd like to try, it remains vital to keep the bike in the proper gear. I may eventually upgrade the rear wheel to a three-speed steel freehub cassette. Most freehubs have aluminum splines, but cheeky bloke built up the strongest one possible, and it's working well with 3000W+ (Lightning Rods drive unit).

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Chalo   100 GW

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Re: BBSHD: I'm skeptical

Post by Chalo » Apr 20 2017 2:05pm

flat tire wrote:Also, there isn't really any elevation where I live so one ratio and a removed derailleur, plus tons of voltage to the motor running a big wheel in the back...you could pump TONS of power thru the bike chain by spinning it really fast!!
In this case, I don't understand what the BBSHD does for you that a cheaper and simpler shafted motor wouldn't do, other than rendering your pedals ineffective.

My first e-bike had a can motor with 12:144 reduction to a left side freewheel on the rear wheel. The right side freewheel and pedal drive were unaffected and functioned normally.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Re: BBSHD: I'm skeptical

Post by flat tire » Apr 20 2017 2:06pm

Open to suggestions if you know of something better.

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Chalo   100 GW

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Re: BBSHD: I'm skeptical

Post by Chalo » Apr 20 2017 2:12pm

Lynch motor or one of its clones? Mars brushless motor?
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Rassy   10 MW

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Re: BBSHD: I'm skeptical

Post by Rassy » Apr 20 2017 2:16pm

they were developed for the awesome handling due to mass centralization and vastly reduced unsprung mass over a hub motor
Good points for an aggressive bike rider, at least if everything holds up for you. Was never a concern on a trike used at moderate speeds on paved surfaces. :D

Like Chalo just said, there have been a number of DIY systems on the forum that drove the rear wheel directly from a shafted motor, similar to what the gas bikes use. Haven't seen any ready to install kits for electric motors.
-Rassy-
One Tadpole Trike equipped with a Bafang BBS02
https://endless-sphere.com/forums/viewt ... 28&t=69419
One Delta Trike equipped with a Bafang BBS02
https://endless-sphere.com/forums/viewt ... 0#p1291260

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Re: BBSHD: I'm skeptical

Post by flat tire » Apr 20 2017 2:22pm

OK I've now changed my target to the Lightning Rods Big Block. Bolt on, maximum power, quiet. but 30 days for production?? wtf...

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r3volved   100 kW

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Re: BBSHD: I'm skeptical

Post by r3volved » Apr 20 2017 2:46pm

The Big Block will take stupid amounts of power...I had my (First Gen) small block kit up to 5kW on a single speed conversion...zero motor/controller issues...all my problems occurred between (and including) the jackshaft axle to the freehub in the wheel. It was fun but it was unnecessary.

Pretty much everything from jackshaft to freehub had been replaced more than once.

At 2.5kW peaks with single speed conversion, it would still eat rear sprockets and chains.

2kW and under with the small block and single speed was a pretty good sweet spot...still can't cheap out on drive train stuff, but with all quality parts it worked real well.
Last edited by r3volved on Apr 21 2017 8:00am, edited 1 time in total.

ions82   100 W

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Re: BBSHD: I'm skeptical

Post by ions82 » Apr 21 2017 2:23am

Perhaps consider a Tangent? Lots of power and very reliable. You pay twice as much but get five times the quality.

Power, reliability, and cheap. Pick two.

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Re: BBSHD: I'm skeptical

Post by flat tire » Apr 21 2017 3:24pm

ions82 wrote:Perhaps consider a Tangent? Lots of power and very reliable. You pay twice as much but get five times the quality.

Power, reliability, and cheap. Pick two.
Now that's a well engineered product. Emailed asking where I can buy as their store link isn't functional.

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Re: BBSHD: I'm skeptical

Post by sather » Apr 22 2017 7:49am

And 5 times the noise (go to about 4 minutes into the video):
https://www.youtube.com/watch?v=xMrqW53RWZQ&t=1s

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Re: BBSHD: I'm skeptical

Post by flat tire » Apr 22 2017 4:11pm

:shock: :shock: :shock: :shock: :shock: :shock:

OK well the Tangent rep got back to me but after seeing that, WTF! there is no way...holy shit.

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Re: BBSHD: I'm skeptical

Post by ions82 » Apr 23 2017 1:51am

That one did seem awfully noisy. Makes me wonder if it has something to do with the bike setup. The Tangent didn't seem nearly as noisy in other videos I've seen.

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