My 2017 Brose Motor, SLOW as molasses, SAD, such a good looking bike..

[FooDoDaddy]

Oh as a side comment I managed to break my key off. A real crappy location for it as others have said. Took some sylicon spray, bobby pin and a small pointed screwdriver to get the broken key out. Sigh... Have to Remember that. I think I'll tie a 2 foot red ribbon on the key so I don't forget.

 

[Trail Cruiser]

Just bought a brand new 2017 Bulls FS2 27.5 Plus with the Brose Motor, went riding with my buddies, they were riding a Bosch and Yamaha, I got dropped big time...When we ride conventional bikes, we ride at the same pace, but on my new bike, I was about 20% slower. I have researched that there might be a possible software solution, has anyone completed their update? Please let me know how I can get this moving......

From the comparisons on these motors, the Brose has lower peak power compared to other motors.

If the above curves are further broken down into torque figures or the twisting force (thanks to 100Cols). Color assignments are slightly different.
https://electricbikereview.com/foru...chart-bosch-yamaha-shimano-brose.14085/page-3

It shows that 2 of the motors lose strength early in the cadence range.

The Brose motor's torque starts dropping above 30 RPM, so the highly touted 90 NM torque is only found at the lower end of the cadence range.

The Yamaha motor's torque drops steeply above 75 RPM. At that cadence, much of the torque to the rear wheel comes from your own legs.

The only way the Brose can surpass the Yamaha is if the cadence is above 85 RPM.

From 75 RPM and above, only the Bosch and Shimano continue to provide ample torque assistance.

This is most likely extracted from a dynamometer reading since the figures are about 15% lower than the advertised numbers. Dyno figures are usually lower since there are efficiency loses at the drivetrain/transmission and the wheels.

By the way, I saw the torque curve of the Bafang BBS and it is similar to the Brose.

Most hub motors also have similar torque curve as the Brose (at full output).

 

[Ken M]

Hi,
I'm fairly confident that tall this performance data is at the output axle of the motors so there is a big impact from the gearing of the bike that is not reflected. Bosch did something that was very smart when they went with the smaller front chain rings spinning at 2.5X the cadence RPM - the smaller chain ring insures that more of the motor torque is provided to the rear wheel at higher speeds. That doesn't allow more than one front chain ring but I think that is not that big of loss for most riders.

Now comes the big debate topic. If you consider that most mid drives suffer huge mechanical losses at higher speeds (for example if running a 44T front to an 11T rear at say 20mph 75% of the torque at the crank axle is lost due to the mechanical gear ratio). This is why most riders of rear hub drive bikes experience better performance at high speeds and why rear gearless hub motors could still be the best solution for urban communing bikes. All the torque the rear hub motor produces is delivered directly to the rear wheel and none of the mid drive motor companies want to discuss this. There is no question that mid drives are superior for mtn bikes (not going to go into those obvious reasons) but they are not superior for fast urban pedelecs for reasons that are just as obvious for anyone that understands cumulative electrical and mechanical efficiencies of the drive system.

 

[Trail Cruiser]

Hi,
I'm fairly confident that tall this performance data is at the output axle of the motors so there is a big impact from the gearing of the bike that is not reflected. Bosch did something that was very smart when they went with the smaller front chain rings spinning at 2.5X the cadence RPM - the smaller chain ring insures that more of the motor torque is provided to the rear wheel at higher speeds. That doesn't allow more than one front chain ring but I think that is not that big of loss for most riders.

Now comes the big debate topic. If you consider that most mid drives suffer huge mechanical losses at higher speeds (for example if running a 44T front to an 11T rear at say 20mph 75% of the torque at the crank axle is lost due to the mechanical gear ratio). This is why most riders of rear hub drive bikes experience better performance at high speeds and why rear gearless hub motors could still be the best solution for urban communing bikes. All the torque the rear hub motor produces is delivered directly to the rear wheel and none of the mid drive motor companies want to discuss this. There is no question that mid drives are superior for mtn bikes (not going to go into those obvious reasons) but they are not superior for fast urban pedelecs for reasons that are just as obvious for anyone that understands cumulative electrical and mechanical efficiencies of the drive system.

While It's true that you suffer greater transmission efficiency loss from mid drives especially at high speeds (like above 24 mph), the hub drives also has an efficiency curve and for the class 3 hub drives, it is less efficient at speeds below 15 mph.

There is an overlap on which both mid drives and hub drives operate at optimum efficiency (somewhere between 15-24 mph). Below 15 mph, the mid drive can be more efficient by taking advantage of gearing and keeping the cadence at the optimum efficiency window (plus it climbs better).

At higher speeds above 24 mph, the extra strain to the drive train of the mid drives adds to the transmission loses and also jeopardizes it's longevity. On the other hand, hub drives operate at their peak efficiency at the upper half of their speed range.

 

[Ken M]

I'm not sure many people / riders understand gear ratios. All mid drives have gear reductions that allow the motor to spin faster (where it will be more efficient) and the torque is amplified - usually around 5-8X. The result is some impressive torque at the cranks given the small size and low weight of the motors.

The issue is that at higher speeds much of this torque is lost due to gearing of the bike itself. This is not an OPINION statement - when you have a 44T front chain ring and an 11T rear chain ring (which is say a good ratio to have a decent cadence at 20-24mph) 75% of the torque at the crank axle is lost due to the gear ratio (ie mechanical inefficiency). This is why at higher speeds a rear hub motor may actually provide more torque to the rear wheel and actually be more efficient overall than a mid-drive.

Bosch's decision to go with a smaller front chain ring that spins at 2.5X cadence absolutely improves high speed performance of the bikes that use their mid-drives. Not until the industry decides to actually document what torque is being provided by the drive systems at the rear axle at the different drive system gear ratios it's not easy to say for sure which is providing the most power across the speeds ridden in different applications. I have eBikes with Yamaha, Bosch and gear hub motors and I know that at higher speeds the hub motor outperforms the mid drives - I can sustain a higher average speed at the same effort level up inclines (unless I slow down enough to get the mid drive back around 15mph or less).

One should keep in mind that the actual max torque of a brushless motor is at stall and this falls as the motor spins faster due to back emf.

 

[rannyv]

Haven't read every one of the replies to this thread, but my objective experience concurs with the charts on this page and what others have reported. Despite having 90NM of torque, I found the Bulls bike with class 3 Brose system to be much less 'snappy' than the Bosch system. Shimano steps, both 6000 and 8000 also seemed less powerful. As for Yamaha, I've no experience.

Would love to try the Specialized offerings that use Brose. I've heard they perform well and they are beautiful bikes. And a system that didn't produce the same whirring that Bosch and other non-Brose systems have would be really nice. I've ridden direct drive hub motors and the quiet power is a pleasant feeling. Too bad most DD motors don't have a decent torque sensor and are front or rear heavy.

 

[Ken M]

Haven't read every one of the replies to this thread, but my objective experience concurs with the charts on this page and what others have reported. Despite having 90NM of torque, I found the Bulls bike with class 3 Brose system to be much less 'snappy' than the Bosch system. Shimano steps, both 6000 and 8000 also seemed less powerful. As for Yamaha, I've no experience.

Would love to try the Specialized offerings that use Brose. I've heard they perform well and they are beautiful bikes. And a system that didn't produce the same whirring that Bosch and other non-Brose systems have would be really nice. I've ridden direct drive hub motors and the quiet power is a pleasant feeling. Too bad most DD motors don't have a decent torque sensor and are front or rear heavy.

I don't think a DD motor should be directly compared to a mid drive motor. The ideal / optimum application for each are dramatically different - mid-drives clearly are best for trail/mtn. ebikes while hub motors are arguably better for fast urban / street ebikes. I'm not going to go into the reasons because they have been the discussion of many forum strings.

 

[Ken M]

While It's true that you suffer greater transmission efficiency loss from mid drives especially at high speeds (like above 24 mph), the hub drives also has an efficiency curve and for the class 3 hub drives, it is less efficient at speeds below 15 mph.

There is an overlap on which both mid drives and hub drives operate at optimum efficiency (somewhere between 15-24 mph). Below 15 mph, the mid drive can be more efficient by taking advantage of gearing and keeping the cadence at the optimum efficiency window (plus it climbs better).

At higher speeds above 24 mph, the extra strain to the drive train of the mid drives adds to the transmission loses and also jeopardizes it's longevity. On the other hand, hub drives operate at their peak efficiency at the upper half of their speed range.

Trail Cruiser,
Your points are correct, but here's what is missed in all this talk. Most people can pedal a traditional bike to 10-15mph and sustain that speed without significant exertion already. Sure a mid drive bike makes that speed range nearly effortless and I have both Yamaha and Bosch ebikes that provide that compelling performance benefit. But, if we ebike advocates believe that the human scale transportation that ebikes provide can be compelling enough to get people out of the cars more frequently I just feel average ebike cruise speeds are going to need to be in the 25-35mph range (no one wants to dramatically increase their commute times if they get on a bike so average speed will matter regardless of what the "I never go faster than 20mph on my ebike" riders think is the safe limit for assist.

 

[Bruce Arnold]

On the other hand, hub drives operate at their peak efficiency at the upper half of their speed range.

I've wondered about this and maybe someone can clue me in. If as you say hub motors are at their peak efficiency at the upper half of their speed range, does that change from PAS level to PAS level? Here's what I mean: to go 25 mph in Eco takes a lot more pedal effort than to go 25 mph in Sport on my CCS. I can easily do 18-20 in Eco on a level road. So is that the sweet spot for Eco as regards efficiency, whereas Sport would be more efficient upwards of 24? Or are we talking about absolute terms, so that the motor is more efficient upwards of 18 regardless of PAS?

 

[Trail Cruiser]

Hi Bruce, this just a simulation but is not exactly the same as the CCS since it has a a torque sensor and this is just controlled via voltage regulation (there are 2 other means of controller regulation, one is via amps and the other is via torque, and the separate torque sensor adds another layer of control). But you get the general idea of how the efficiency curve looks like at different speeds.

Here is a simulation using a Bafang motor and 48 volt battery. The green curve is the efficiency curve. The vertical dashed line is the speed for each PAS level. If you want to ride at a really low speed such as 10 mph or less, you can just put your PAS to 0 and then feather the throttle every now and then.

http://www.ebikes.ca/tools/simulato..._500&batt=B4812_MH&wheel=27.5i&hp=50&axis=mph

 

[rannyv]

I don't think a DD motor should be directly compared to a mid drive motor. The ideal / optimum application for each are dramatically different - mid-drives clearly are best for trail/mtn. ebikes while hub motors are arguably better for fast urban / street ebikes. I'm not going to go into the reasons because they have been the discussion of many forum strings.

Wasn't comparing all aspects of DD to mid-drive. Mostly just the silent operation aspect of DD to that of Brose.

 

[Ken M]

Just thinking out-load...given how DD hub motor efficiency is not very good at low speeds (like <10mph) it seems a good idea is to just have the rider achieve that speed with their own power before allowing the motor assistance to kick in. This would probably allow DD hub motors to average the efficiency of a mid-drive while having the benefit of better high speed performance.

 

[rannyv]

The graphs and charts are all fine, but my experience with the 48V DD motor was that it had plenty of power for climbing, even when coupled with a heavy bike. Also, it doesn't need to be shifted as frequently as a mid drive. But this is hijacking the original thread - 'Brose is slow' something like that.

To Brose / Specialized experts - does the Specialized Brose tuning make a difference?

 

[Ken M]

There is just far too much subjectivity on the subject of relative performance of the different drive system brands and mid-drive vs hub drives. I think the Bosch system has a slight advantage vs the other mid-drives because the 2.5 faster rotation of the small chain ring allows more of the motor torque to be delivered to the rear wheel at higher speeds but having only one chain ring could be a factor to some riders as total gear ration range is lower vs having 2 or 3 front chain rings as other mid-drives allow.

I'm still believe hub motors have a definite design advantage when an ebike is assisting at higher speeds simply because the torque of the motor is directly applied to the rear wheel and does not suffer any mechanical losses of gear ratios thru the the front to rear chain rings. Of coarse, none of the mid-drive manufacturers (and this is where the bulk of the ebike money/market is going) are going to talk about this inherent design weakness so companies like Stromer, Juiced Cycles, Magnum, etc. that utilize hub drives on their eBikes need to do a better job educating riders that would like their ebikes to be the best high speed performance configuration possible.

 

[AHicks]

People can't generalize on the fact we all want to go fast (>25mph). That's simply not true. When talking about "best", or the way it should be, you need to define your mission (commuting for instance).

I do agree though, that any benefit gained by a gear driven motor is starting to disappear long before speeds like that (>25mph) are attained - for a lot of reasons.

Something I don't think has been mentioned is the fact that DD motors can be wound for different missions. They can be all about low speed torque, all about mid range, or high speed. In many cases, they can be ordered to turn a specific rpm when wide open (540 rpm for instance, mid range). If we compare a relatively low speed wind to a gear driven setup (take your pick rear or mid), some of the big advantages of the gear driven system start to fade. DD motor we see in production bikes may already be using that science (derated to achieve torque?).

Last, not a purist or off road fanatic, and I don't notice the heavier rear end on my DD bike, as compared to a 700c Trek I was riding before converting to e-bikes (unless I'm lifting it!). My opinion, as a non commuter, riding cuz I want to.

 

[rannyv]

People can't generalize on the fact we all want to go fast (>25mph). That's simply not true. When talking about "best", or the way it should be, you need to define your mission (commuting for instance).

I do agree though, that any benefit gained by a gear driven motor is starting to disappear long before speeds like that (>25mph) are attained - for a lot of reasons.

Something I don't think has been mentioned is the fact that DD motors can be wound for different missions. They can be all about low speed torque, all about mid range, or high speed. In many cases, they can be ordered to turn a specific rpm when wide open (540 rpm for instance, mid range). If we compare a relatively low speed wind to a gear driven setup (take your pick rear or mid), some of the big advantages of the gear driven system start to fade. DD motor we see in production bikes may already be using that science (derated to achieve torque?).

Last, not a purist or off road fanatic, and I don't notice the heavier rear end on my DD bike, as compared to a 700c Trek I was riding before converting to e-bikes (unless I'm lifting it!). My opinion, as a non commuter, riding cuz I want to.

We should probably go back to a DIY hub driven bike vs. off the shelf mid-drive thread. This is interesting, but off topic for the Brose motor. "My bad" for adding DD motor into the mix in my earlier thread.

 

[FooDoDaddy]

It's been a year, and my upgrade hasn't hurt it one bit! Just last week I went on a 20 mile bike ride (some off road), central Phoenix canal system. anyway, on level ground, maxed out full pedaling I got around 32 mph (va gps)! Of course my HR is over 180 at speed, but it's a blast. It also has 20 gears, and can climb anything in 1st. It's now Beast mode ready. Climbs like a banshee My Modified E-Stream EVO FS 3 29er

Best $100 I've spent.

This hasn't affected the bike in anyway, other that reported speed. I use my garmin watch speed/gps so no worries.

I love the Brose motor, and that just makes it sing. Again, no fears about the motor. The keys on the other hand suck.

 

[The duke]

Ok guys. 2 years have passed since this thread was started and technology has improved. E-Mountainbike has done one of the most extensive mid drive motor comparisons to date and it anoints the Brose S Drive as the best. Not fastest or most torquey, but "its full fledged power and natural riding feel" makr it dominant. It kicks the others' butts pretty handily. What say you guys?

Mid drive motor comparison

 

[Ken M]

Sounds like a pretty tight field. I would tend to think the torque of the TQ motor would be compelling to riders just wanting the best climbing experience possible.

I tend to ride mostly on the road so I've just grown fond of the simplicity and reliability of a powerful hub motor. I understand that not having the weight centered makes them virtually unusable for serious trail riding.

 

[E-Wheels]

Ok guys. 2 years have passed since this thread was started and technology has improved. E-Mountainbike has done one of the most extensive mid drive motor comparisons to date and it anoints the Brose S Drive as the best. Not fastest or most torquey, but "its full fledged power and natural riding feel" makr it dominant. It kicks the others' butts pretty handily. What say you guys?

Mid drive motor comparison

Short term reviews and ratings is one thing Owning and using over the long term is another
I wonder if long term owners would agree with the reviewers ratings