1500w Leaf bike DD hub with 7s vs. 1500w Geared Hub drive hub with 1s....what would you prefer?

[ebike4healthandfitness]

Assume both set-ups are equally reliable when maintained. (Leaf bike 1500w would need more pedal drive train maintenance but less motor maintenance compared to the geared hub with single speed pedal drive train)

1500w bike Leaf bike DD motor has peak efficiency of 90%.
1500w Geared hub motor has a peak efficiency of 83%.

Which one would you choose and why?

Would you want multiple rear pedal drive train gears but lower motor efficiency at low speed or would you prefer a single speed pedal drive train with higher motor efficiency at low speed?

How much is maximum tire width a factor? The single speed pedal drive will allow for a wider rear tire.

 

[ebike4healthandfitness]

One of the reasons I asked this question is because I find the combination of powerful DD motor and 7 speed pedal drive train a curious one.

I mean why use 7 speed pedal drive when you got 1500 watts or more power on tap? The only reasonable reason I can think of is hills. Indeed this is where a DD motor can overheat due to low efficiency and thus a rider using the pedal drive can help the motor and potentially keep it from overheating.

With that noted, a geared hub motor is much more efficient at low speed and thus could potentially climb hills on motor alone. The 1s pedal drive potentially being just icing on the cake rather than a necessity like the 7s drive is on the leaf bike motor.

Same goes for a more a powerful DD motor (e.g. 45mm wide stator) with 1s pedal drive train.

Perhaps the best way to use leaf bike 1500w is on pre-built ebikes with integrated mid drives. In a scenario like this having gears on the back helps the mid drive. Unfortunately leaf bike has no product for this category as all the pre-built ebikes with integrated mid drives have drive trains incompatible with the leaf bike 1500 watt 7 speed cassette hub.

 

[99t4]

1500w bike Leaf bike DD motor has peak efficiency of 90%.
1500w Geared hub motor has a peak efficiency of 83%.

Which one would you choose and why?

Would you want multiple rear pedal drive train gears but lower motor efficiency at low speed or would you prefer a single speed pedal drive train with higher motor efficiency at low speed?

How much is maximum tire width a factor? The single speed pedal drive will allow for a wider rear tire.

Personally I prefer 1500W rear DD hubmotor, 7sp rear, 2 or 3 chainring front. Why? I like to pedal hard and near to my preferred 90 RPM cadence. That gives enough gearing choices for that. And I prefer the near silence of the DD.

I Tried fat tire-- not for me. Don't need the flotation, could not get used to the imprecise handling and heavy feeling. 2.35" tire width has been doing well on both my hardtail cargo bike and FS downhill bike.

Predicting you will get answers all over the map as it depends on rider preferences and riding environment conditions. Why are you asking?

 

[ebike4healthandfitness]

I prefer 1500W rear DD hubmotor, 7sp rear, 2 or 3 chainring front. Why? I like to pedal hard and near to my preferred 90 RPM cadence.

If you like to pedal along with the motor for health, strength and endurance benefits I applaud you for being someone that seeks to keep themselves fit.

Just keep in mind at higher speeds pedaling along at 90 rpm may actually reduce your battery life compared to not pedaling at all and just letting the motor do all the work! While I know that sounds counterintuitive realize pedaling at 90 rpm creates more drag than not pedaling. Therefore various situations exist where the act of pedaling ironically reduces battery life because extra watts from drag is more than the watts contributed by pedaling.

If you don't believe me just plug in some examples using both cadence of 90 and cadence of 1 in the following calculator:

Bicycle Speed (Velocity) And Power Calculator

Bicycle Speed (Velocity) And Power Calculator, comparing different kinds of bicycles

www.kreuzotter.de

 

[E-HP]

I have a DD hub. I switched to a 6 speed freewheel to get better clearance, but only use the 13 tooth cog. I last shifted about 4 months ago, down one gear then back up (chain was making some noise, Hills where I ride average between 12%-15% and about 20% max for steeper sections, and 46:13 allows me to provide pedaling assistance up to around 20 mph for climbing and keeping the temps in check.

I monitor my usage closely, and haven’t seen a case where usage went up when pedaling. I stay mainly between 18mph-20mph, and pedal for exercise, for some additional range, and for show.

 

[99t4]

If you like to pedal along with the motor for health, strength and endurance benefits I applaud you for being someone that seeks to keep themselves fit.

Yes quite true. Also, I feel guilty (however unfounded) letting the motor do all the work.

Just keep in mind at higher speeds pedaling along at 90 rpm may actually reduce your battery life compared to not pedaling at all and just letting the motor do all the work! While I know that sounds counterintuitive realize pedaling at 90 rpm creates more drag than not pedaling. Therefore various situations exist where the act of pedaling ironically reduces battery life because extra watts from drag is more than the watts contributed by pedaling.

If you don't believe me just plug in some examples using both cadence of 90 and cadence of 1 in the following calculator:

Bicycle Speed (Velocity) And Power Calculator

Bicycle Speed (Velocity) And Power Calculator, comparing different kinds of bicycles

www.kreuzotter.de

I have no reason not to believe you but we must admit that the simulator may be flawed in this aspect. Why? In my real life experience your theory does not prove true.

My usual cruising speed on level-ish ground is 17-22 MPH (cruise control set). Glancing at my display amperage output readout, EVERY time I stop pedaling the amp output increases. When I resume pedaling it decreases. Therefore I don't see how your statement "Just keep in mind at higher speeds pedaling along at 90 rpm may actually reduce your battery life compared to not pedaling at all and just letting the motor do all the work" applies here.

 

[ebike4healthandfitness]

My usual cruising speed on level-ish ground is 17-22 MPH (cruise control set). Glancing at my display amperage output readout, EVERY time I stop pedaling the amp output increases. When I resume pedaling it decreases. Therefore I don't see how your statement "Just keep in mind at higher speeds pedaling along at 90 rpm may actually reduce your battery life compared to not pedaling at all and just letting the motor do all the work" applies here.

I was thinking 35 mph or greater for pedaling which you see mentioned in the leaf bike 1500w thread and elsewhere.

According to the calculator when a 75 lb roadster bike with wide high pressure slick tires and a 6' tall 190 lb rider is traveling 35 mph pedaling at 90 rpm (compared to 1 rpm) creates an additional 169 watts of drag.

169 watts of additional drag at just 35 mph is pretty substantial. That means a pedaling effort of 169 watts wouldn't help extend battery life in the slightest.

40 mph at 90 rpm (compared to 1 rpm) would create an additional 252 watts of drag.

For someone concerned about getting from point A to B this is something definitely to consider if the goal is to make the most of both battery reserves and human muscle/endurance reserves.