350w hub versus 250w mid-drive, who wins?

[emco5]

I’ve received theory and recommendations on this subject, but I’d appreciate feedback from someone who has 'actually experienced' both power systems. Your hands-on opinion is good enough, no need to argue variables and the grey areas. Speed doesn't matter, either.

Bike-A has a Bafang 36v 350-watt geared hub with thumb-throttle, and its granny gearing is the common 28t chainring with 32t rear cog.

Bike-B has the 36v 250-watt Shimano STEPS mid-drive PAS system with manual shifting. Its granny gearing is 44t chainring with a 32t cog in back.

Both bikes have identical geometry, weigh the same, and have the same tires.

Ridden by the same person up a 9% hill for 1/2 mile, which bike would get to the top with less rider effort?

 

[harryS]

You have to ride a low powered bike to understand that they're not electric motorcycles. They're pedal assisted bicycles, optimized for to run a little faster than your average rider on a regular bike.

In my opinion, both will burn up on a 9% hill if the rider isn't working hard.

 

[TrevorB]

I replaced 44t to 38t on Steps, made all difference on steeper hills having extra gear.

 

[emco5]

Thank you, HarryS, for the input. I've owned four power-assisted bikes in the last ten years from 250w to 500w, so I get it. Looking for rider experience comparing the 350w hub against the Shimano STEPS. The smaller STEPS system has a torque rating of 50 Nm while the Bafang hub makes a bit less at 45 Nm. If Shimano's chosen gearing doesn't interfere, and their mapping is dialed, it could be a better climber. I suspect, though, that the Steps torque number is reached only at peak rider input which would not reduce rider fatigue. Although I've not seen the Bafang's power curve, my rides on one felt like its torque peaked almost immediately.

 

[harryS]

Sorry. So many people expect to go up w/o pedaling. In that case, my opinion is that the highest gearing should be easiest on the motor, and on the rider too, just like Trevor mentions.

I also think a mid drive is preferred because gearing can multiply the torque for both the rider and motor. It can be kept spinning faster at a given speed and be more efficient. Meanwhile, maybe the hub motor is bogging down because it only goes as fast as the wheel.

Watts are rarely equal anyway, except in a thought experiment. Manufacturers will fudge their numbers lower to make a bike legal in one country and fudge them higher for better marketing in another country.

 

[emco5]

In case anyone else is curious, I will answer my own question. The weather cooperated during the week and I had some free time, so I found a dealer with a Trek manual-shift Shimano Steps mid-drive demo. I did some riding up a 10% hill and discovered that compared to a 36v 350-watt geared hub, the 36v 250-watt mid-drive was the winner. With the hub, it helps you as long as you help it. That means on long grades steeper than 6% you work a lot to keep the bike’s road speed around 10-12mph to stay in the hub's power band and avoid potentially cooking the windings. The Steps had a 10-cog rear cluster with a 32t granny and on the test hill it never sagged or felt over-loaded, even if I dawdled along. Accelerating just required a little more pressure on the pedals, or down-shifting one or two clicks which increased crank rpm and really bump up boost energy. The system regulates power output at three levels: Eco, Normal, and High. On the test hill its Normal mode at a moderate cadence of about 60-70 crank rpm felt very close to the strength of a 350w hub. In the High power range it was simply no contest. In my opinion, the 250 mid exceeds the climbing ability of a 350 geared hub, and with much less effort. It was impressive. What intrigues me is how efficient a small motor can be with smart software and good gearing.

 

[tomjasz]

Hub drive wins for simplicity on the flats. IF you have hills, mild grades can be challenged with a gear driven hub. Significant grades, mid drives are king.

 

[Larry Ganz]

We live in a hilly area, and our Trek mid-drive eBikes are a breeze to ride up steep (10% or more) hills, using the proper gearing to get a good cadence rate and power delivery. Mine is a Powerfly 7 eMTN bike with 75NM Bosche system, and my wife's is a Neko+ trail/hybrid with 50NM Shimano Steps system.

Before buying, I test drove a friend's 350 watt hub motor eBike with my 215 lb weight, and if my speed dropped too slow then the motor assist became useless as it fell below it's powerband. With the Trek mid-drive (including the Dual Sport+ with Steps that I test rode before buying) we can drop to first gear and pull the hills in the lowest assist mode (ECO) at 4-5 mph, or kick it up to 200% assist (HIGH or SPORT) and fly up the hills at over 10-15 mph. We tend to use the least amount of boost that will allow us to climb, to get a better workout, so we'll use the lower two power levels the most, even if it means going slower. At those slow speeds the hub motor could not help propel me uphill.

So, after putting 115 miles on our bikes in the first month of ownership, with big elevation changes and climbs on each ride, I could not see myself going with a hub motor for pedal assist. I like how well the mid-drives integrate both torque sensing and cadence into calculating the boost, and how they allow the gears to assist the motor for climbing. On steep mountain bike trails the 300% boost of the Bosche has come in handy in the lower gears when I can't go fast to keep up momentum, but need to power through a tough climb over rocks and roots.

 

[tomjasz]

I don't think I've ever read any review of eBikes suggesting a hub drive be used riding hills and dales! Although I think my newest 2WD geared hub motors may be the exception. Thanks for the over view. I'm quite excited to be trying both those motors very soon. Which do you like better? And why?

 

[Bike_On]

In case anyone else is curious, I will answer my own question. The weather cooperated during the week and I had some free time, so I found a dealer with a Trek manual-shift Shimano Steps mid-drive demo. I did some riding up a 10% hill and discovered that compared to a 36v 350-watt geared hub, the 36v 250-watt mid-drive was the winner. With the hub, it helps you as long as you help it. That means on long grades steeper than 6% you work a lot to keep the bike’s road speed around 10-12mph to stay in the hub's power band and avoid potentially cooking the windings. The Steps had a 10-cog rear cluster with a 32t granny and on the test hill it never sagged or felt over-loaded, even if I dawdled along. Accelerating just required a little more pressure on the pedals, or down-shifting one or two clicks which increased crank rpm and really bump up boost energy. The system regulates power output at three levels: Eco, Normal, and High. On the test hill its Normal mode at a moderate cadence of about 60-70 crank rpm felt very close to the strength of a 350w hub. In the High power range it was simply no contest. In my opinion, the 250 mid exceeds the climbing ability of a 350 geared hub, and with much less effort. It was impressive. What intrigues me is how efficient a small motor can be with smart software and good gearing.

The beauty and benefit of a mid - drive system. Dial in the gear for peak efficiency and power.

The beauty of the hubs on flat and mild hills is the variation in pedal cadence allowed by the motor. The mid drives will dictate a certain rpm, with a narrow band of cadence. The hubs allow for a wider rpm cadence and feels more natural.

 

[Larry Ganz]

My favorite features of a mid-drive are not just the ability to take advantage of the gears to optimize torque delivery, or the low center of gravity with low unsprung weight, but the torque sensing capability.

I can vary the power delivery based on how hard I push on the pedals, so when I transition from flat ground to a climb the power delivery goes up as I pedal harder, without me having to turn up the assist level or a throttle.

 

[tomjasz]

My favorite features of a mid-drive are not just the ability to take advantage of the gears to optimize torque delivery, or the low center of gravity with low unsprung weight, but the torque sensing capability.

I can vary the power delivery based on how hard I push on the pedals, so when I transition from flat ground to a climb the power delivery goes up as I pedal harder, without me having to turn up the assist level or a throttle.

Something we'll soon see from Bafang as well!
(Link Removed - No Longer Exists)

 

[Bike_On]

My favorite features of a mid-drive are not just the ability to take advantage of the gears to optimize torque delivery, or the low center of gravity with low unsprung weight, but the torque sensing capability.

I can vary the power delivery based on how hard I push on the pedals, so when I transition from flat ground to a climb the power delivery goes up as I pedal harder, without me having to turn up the assist level or a throttle.

I agree that pas has nice user freedoms. Hubs have PAS is a few of them too.

Throttle is nice from a stop light , to get moving quicker.

 

[Matt A]

I agree with a lot of what I read on this thread. To use the most motor power or be most efficient at a certain cadence with the Bosch system, it is true that the cadence is sort of narrow. However, I have the performance speed line Bosch motor, and Bosch requires a higher cadence for max efficiency, which really seems to me to translate into max power output, not battery usage as a percentage of motor output. I use the Nyon which gives a very detailed description of power input and output.

If you want a slow cadence, I noticed you can just move into a higher gear, and arrow up to Sport or Turbo. You will get the same power as Tour or more if you have a slow cadence in Turbo. The motor power meter will display at around half but up to 3/4 full, so you have your slow cadence with the same power you'd have in max output Tour or Sport. Using the Nyon, I have seen that actually achieving max motor output requires serious input, with the Intuvia the motor output always showed max while in turbo as long as I put in a slight effort. With the Nyon, it is much more detailed and shows that you can achieve any cadence you want without compromising power by increasing or decreasing your assist level.

In Turbo, my bike normally gets a range of 50 miles when fully loaded and riding at 25 mph with frequent stops. When I experimented in all Turbo with a slow cadence, leaving the motor power meter closer to half most of the time, I experienced a 75 mile range under the same conditions.

 

[Larry Ganz]

Why can't they make the Nyon an easy upgrade for people in the USA, without jumping through hoops to get it from the UK and create a UK persona to set it up?

 

[Matt A]

Why can't they make the Nyon an easy upgrade for people in the USA, without jumping through hoops to get it from the UK and create a UK persona to set it up?

Yeah it makes no sense, I have heard it's a liability concern over here, so I guess we have to blame the way Americans as a whole treat consumer products, and need them to be idiot proof. Any accident and people love to run to lawyers that can find some crazy ways to place blame.

I purchased the Nyon on ebay, and downloading the app was surprisingly simple just had to make a new itunes account with a fake address, I used a bank in the UK. I have all my old apps and everything works fine on the phone, you don't log out of iCloud so you keep everything. It went a lot smoother than I thought it would based on previous threads. I even purchased the app upgrades by buying a GBP itunes gift card code on eBay. Took 30 seconds to redeem it and purchase the upgrades. This is all with an iphone of course, can't speak for android experience.

 

[Matt A]

Why can't they make the Nyon an easy upgrade for people in the USA, without jumping through hoops to get it from the UK and create a UK persona to set it up?

By the way when I purchased the Nyon on ebay it was on my bike with everything working perfectly in just 7 days.