Although last time I was in LA I swore I was never ever going back, here I am again at the Lunacycle HQ spending several hours a day sitting in traffic. How do people live like this? No wonder ebikes are so popular here in Southern California. People can get an ebike and commute on the bike paths along the ocean and avoid the traffic completely. If I lived here I’m sure I would do the same.
I got my hands on one of the first prototype of Bafang’s 1000W Max Ultra Torque sensing mid drives and I was able to ride it around for a few days in the horrendous LA traffic and on some light trails and grass using my 52v GA Shark pack. This article is about my first impressions of this drive and why I think they still have a way to go to get to the level of refinement of the BBSxx series mid-drives.
The first thing you notice about the Max Ultra is that it is heavy, too heavy (11.7lbs). The 350W torque sensing Bosch and Yahama mid drives are built out of very thin aluminum and lots of plastic gears. The Max Ultra is a monster and it has a much too thick cast aluminum case. I’ve noticed that designing the mid drives with much too thick cases is a problem you see with the BBS02 and BBSHD as well. I’m not sure if Bafang just doesn’t care about the weight or is worried about people smashing open the drive unit by beating it on logs and rocks. I doubt you will be able to crack this case no matter how hard you smash it on a log pile.
The Bafang Max I tested was mounted on a craptastic low-end fatty with a steel spring fork suspension
The power delivery was smooth and stopped as soon as you stopped pedaling. The feeling of riding this drive unit was almost identical to what you feel when riding a BBS02 properly programmed with Karl’s Special Sauce. The only difference was that you didn’t have to push really hard to get the bike moving initially, when you press on the pedals, it just goes. This helps you feel more like a superman and that the bike is just an extension of your body rather than an electric motor helping you out. I preferred the ‘feel’ of the Max Ultra to the BBS02 but the unit’s benefits are outweighed by the massive weight of the drive unit. I have been told that the prototype is heavier than the production model is going to be. The unit I tested was programmed for 18 amps, although I have no idea what the production amp limit will be. If you can run a 60v pack on an 18 amp drive unit that levels out to about 1080 Watts so there is a good chance that the production unit will still only run at 18 Amps.
The chainring was narrow wide but I felt like it was mounted a little too far away from the bike
All the connectors for the Ultra Max seem to be compatible with the BBSxx series so you can swap around displays, throttles, and ebike cutoffs as much as you want. The thumb throttle is a nice addition that is missing from a lot of low power mid drives like the Bosch. I appreciated having the throttle although I have to admit I never used it. The Max Ultra prototype had a DPC-10 display with 5 power levels which is my least favorite of the BBSxx displays. I hope that you will be able to get the Max Ultra with the DPC-14 color display when it comes out.
The drive unit is not much more ‘stealth’ than a BBSxx, a little mud camouflage will help keep it hidden
At one point when testing the Ultra Max I had gotten off the bike and was pushing it along while walking alongside it and the bike just took off on its own. I was able to get the bike back under control again but every time I pushed it the bike would take off. The pedals were not turning when I pushed the bike so I don’t know how or why this was happening, but after cycling the power I could never get that behavior to repeat. To be fair I was riding an old prototype and I’m hopeful that the bugs will be worked out of the system before it hits the shelves.
Rendering shown with a chainguard which my prototype I tested did not have
Power of the Ultra Max vs the Bosch mid drive system
When it comes to the amount of power the Ultra Max delivers when compared to other torque sensing mid drives I have to say there is really no comparison. I would say that the Ultra Max felt about 2.5 times more powerful than the Bosch 350W drive unit and it should be available for a small fraction of the cost of a Bosch. Clearly, there is a market for the Bosch Mid-drive (Europeans and Australia), I’m just not in the ultra low power lover market demographic. The Ultra Max felt like it had enough power to plow through more snow than most people would ever want to ride through, and it is a real demon when you take it off-road. It still ‘feels’ like you are riding an ebike and not some kind of ultralight motocross machine like the Tangent drive system.
Notice that this drive unit lists 3 different operating voltages of 43,48 & 60. This leads me to believe that you may be able to run this drive with a 60v nominal pack to really make it sing
Will I be able to program it?
This really is the million dollar question. Bafang is not particularly happy about people being able to program the BBSxx series drives which just about everyone seems to be doing nowadays. The reality is if people are willing to accept responsibility for their programming changes and eat the cost of a new controller or parts if they damage them, then what is the problem? The biggest difference between the Bafang Ultra Max and the Bosch mid drive is not the power or the price but rather the ability to custom program it, use it with a variety of batteries and the warranty repairs. With the Max Ultra you must rely on the company you bought the drive from for warranty repairs or fix it yourself. With a Bosch you’re absolutely locked out of the programming and don’t even think of opening up your drive unit. It will immediately void any warranty. I don’t own products that I’m not allowed to fix and can’t get parts for, so I’ll never own a Bosch or Yamaha mid drive unit. I can tell with some certainty there will be an Ultra Max in my future and whether Bafang wants me to or not, I will be finding some way to program it on my own.
If you’re hardcore you can try to get your hands on a mounting bracket and weld it to your own custom frame. Sounds like too much like work.
A need for custom frames
The Ultra Max will not fit on any bike, you will need a custom frame with a ‘bottom bracket’ that will accept the drive unit. Lunacycle is working on having custom full suspension and fatty frames built for the Ultra Max and there is a good chance that you will be able to buy a ‘kit package’ that comes with the frame and the motor and you can just load up bike components off another bike onto the Ultra Max frame. Although this will turn some people off, I really like that setup and I can easily move all my components from one bike to another in about 2-3 hours. I’m sure there will complete ebikes built with the Ultra Max drive system available for sale as well, but that is at least another 4-6 months away. There are some people like Roshan from Biktrix that are way out ahead of the curve and are already building frames for the 350W Max Bafang mid drive which will work with the Max Ultra as well.
The Bafang 350W Max drive works with a 36v battery and does not work with a 48v or higher pack, but the Max Ultra works fine with a 52v pack which is what I tested it with. I’m not sure I would want to use this drive unit with a 48v pack, as the power would almost certainly be noticeably less. Although I would very much like to be able to use 60 and 72v packs with the Max Ultra, it is unlikely that the HVC will allow people to do that.
The original Bafang 350W Max system (yawn) being sold on Alibaba. Note the crappy cable connectors, the new Ultra Max has the nice Higo style waterproof connectors. I wonder if the eraser comes with it.
No speed limits
The nicest thing about the Bafang Max drive is there are no speed limits. The bike easily gets over 30 mph with a 200lb rider on the level and over 35mph on slight downhills. It is no problem keeping up with LA traffic on the side streets as long as you stay on the shoulders on the main drags. The Bosch and Yamaha are both completely rigid with their speed limiting although there are defeat devices you can mount on your mid drives to make them think you’re going half as fast as you really are. Yay for defeat devices, stick it to the man. I wouldn’t worry about it too much though because a 350W drive unit is not going to be able to go much over 20mph anyway unless you’re going downhill or have a rocket strapped to your back.
I felt about 3 distinctly different power levels based on how hard I was pushing the pedals on the Ultra Max. The Bosch, by comparison, seemed to have a nearly infinite number of sensitivity levels for pressure. Honestly, I felt like 3 levels were enough. There was barely pushing the pedals at all (clown pedaling), normal pedaling, and I’m being chased by a bear pedalling which each gave different levels of assist. The setting of the power level on the display seemed to have much more to do with how much power you get to the wheel than how hard you press on the pedal.
I tested this unit with a cheap 32T 8-speed cassette which I would NOT recommend. A 42-11T 10 speed with a decent derailleur would be much more preferable
At one point the chain came off the front ring and it was a real pain to get it back on. I would say make sure to turn off the drive unit when replacing thrown chains, as you don’t know what the torque sensing mid drive is going to do when you’re yanking its chain. It would suck to get your fingers chewed off by the chainring because you were sloppy. The bike is also sensitive to pedal pressure. If you accidentally press on the pedal without meaning to, it will work like accidently tapping the throttle and the bike will just take off. I think that from a safety standpoint this is an issue that does cause me a little bit of concern.
Would I recommend the Ultra Max for public consumption? The prototype I rode had a lot going for it. The biggest problem I found was the weight and the need for a custom bike frame. I liked the torque sensing capability, but having to have a custom frame to mount the drive unit on is a huge drawback as most people who are really into bikes already have a pretty expensive frame that they probably don’t want to just strip off and throw away. I guess the big questions will be how much will it cost when it comes out, will I be able to program it myself, and will we be able to hook it up to 60 or 72v packs and have it work without blowing mosfets, or will the HVC prevent that from happening? Time will tell, but make no mistake, this will certainly be the first torque-sensing mid drive in my sizable ebike fleet. I’ll write more once I get my paws on a production unit. Stay tuned.
Ride On.
