BBSHD: I'm skeptical

[flat tire]

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?

 

[Chalo]

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.

 

[Wheazel]

Should you ditch the bbshd idea?
Probably

Also what Chalo said.

 

[Ykick]

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.

 

[r3volved]

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

 

[flat tire]

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.

 

[PRW]

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!

 

[flat tire]

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.

 

[fechter]

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.

 

[Rassy]

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.

 

[flat tire]

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.

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.

 

[spinningmagnets]

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).

 

[Chalo]

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.

 

[flat tire]

Open to suggestions if you know of something better.

 

[Chalo]

Lynch motor or one of its clones? Mars brushless motor?

 

[Rassy]

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.

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.

 

[flat tire]

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

 

[r3volved]

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.

 

[ions82]

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.

 

[flat tire]

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.

 

[sather]

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

 

[flat tire]

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

 

[ions82]

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.

 

[joeyzzzz]

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).

Did you ever increase to 2kW with the BBSHD? If so, what method did you use?

 

[spinningmagnets]

A while back, Luna was selling 50A ludicrous controllers, which allowed me to keep the 52V battery packs that I like very much.