A lot has been written on this forum about this topic, and while it's very challenging to speak generally without getting into comparing specific ebikes, here is what I believe you'll find generally to be true:Hi Mike,
Thanks for sharing that information on the hub drive bikes. Do you have any comments on when mid-drive bikes make jmore sense? Hill climbing mountain bikes?
• both mid drives and hub drives will work for pretty much any specific riding condition you choose, whether it's trails, mountain biking, flats, hilly, gravel. There are a few caveats with each.
• with hub drives if you regularly face steep hills, (more than 12% incline) and are a heavier rider who is not in good shape, you want to choose a bit higher wattage motor , likely 500, that also has a torque rating of at least 50 Newton meters (nm). Whereas with mid drives, the majority of them are not rated above 250 watts, and a NM rating of 40nm will likely still be ok for steep hills, due to the fact you can leverage multiple gears at the exit of the power delivery through the chain and cassette before it is delivered through the wheel. Just like you would do on a non electric bike and downshifting as low as gear 1, for the steepest of hills.
• generally most mid drives will operate at 36 volts, while hub drives are available at 48 volts, 52 volts, and some even higher. The mid drives can still achieve the higher torque levels (I.e. 80 is really strong) despite the lower 36 volts. Some mid drives can achieve 160 nm (bafang is one for conversions) but the vast majority of riders will likely find they just don't need or even want 160nm as you can go through chains and cassettes faster due to higher strain.
• for hub drives if you regularly want to achieve speeds over 20 mph, you definitely want to make sure it's achieved through a system rated at 48 volts.
• torque sensing found more commonly on mid drives, but can be found on hub drives (rarer, and IGO, Surface 604, and juiced do offer torque sensing), will feel a bit smoother and more 'natural' like a regular bike since the motor responds to foot/leg effort, instead of simply crank arm/pedal rotation. The torque sensing can allow for a greater 'range' for a given size battery, but remember you are actually doing more of the work, than you would with cadence sensing or pedal rotation based signal and power delivery. Mid drives can be optimized and designed for a bit better efficiency which will help the range as well, since they can spin at higher rpm, and have more flexibility with internal motor gearing. There are gears in hub drive motors, but efficiency optimization is more limited in the designing of it, since you are limited to the rpm of the rear wheel.
• some people will generally say mid drives are 'better' for hills, however that over simplifies and leaves a wide range of what the definition of 'better' is, thus making it highly subjective.
• in terms of reliability , there are simply too many variables for each design, to pin that down to a carte Blanche statement.
• hub drives are generally quite a bit less expensive , in first cost, and repairs, and mid drives usually aren't seen on many ebike models below the $2500 price point. Though those thresholds are being challenged.
Not sure if any the above helps. But I will say generally you can find good quality, good performance, etc in both types of drives. From there the topic can get really 'passionate' and it's like watching a Chevy Truck owner Duke it out with a Ford truck owner as to who's is 'better.'