Would it be correct that the Stromer system actually prolongs chain/ sprocket intervals ?
Yes very significantly.
—Compared to non assisted pedal power wear: as the boost from the hub sort of balances the the torque/pull from the chain??
You are pulling chain forward with drive but motor is powering wheel forward which relieves or balances some of that pull?
True. The worst case wear will be equal to a regular bike. For the most of the time hub motor will have significantly less wear. When the hub gives support it actually decreases the tension on the chain.
— And X2 for wear when compared to mid-drive road bike It will eat components even faster. All that extra torque on chain and cogs
Yes. Mid drives transfer all of the power through the chain so the effect is the exact opposite of the hub drives. For mid drives , the wear on the chain is significantly increased compared to regular bikes.
— And X5 for mid drive mtn bike?? Which will gorge on the driveline from all that low gear torque multiplication.
For mtb's mid drives are the best for several reasons. The main advantage is mid drives make use of the gearing hence will be easier to cover/adapt to gnarly terrain. And weight distribution may be preferable for mtb'ing since the bike is getting tossed around at quite frequently( however the rider weight has a far more significant effect on this compared to the bike itself) .
My Stromer chains seem to last very long time. I lube and wipe down chain and sprockets with dry cloth after every ride.....any dirt on chain ext seems to be the real killer.
As others said, mid vs hub discussionrarely highlight this but it seems like a big deal.
Agreed. That is why I have switched to wax and so far it has been amazing. Very little to no dirt gets on the chain and so far no significant measurable chain wear after 1000 miles.
I have to address a couple of false statements here.
Mid drive bikes go faster and further using smaller motors and less battery power by leveraging their effort in a more seamless way along with our effort through the chain and cassette to the rear wheel.
This sentence is completely false.
First of all mid drives do not go faster and battery consumption completely depends on how the bike is ridden, the motor parameters and speed. If anything quality hubs are going to be faster since they do not suffer from drivetrain losses. For the same reason at higher speeds hubs are also more efficient. At very low speeds(like when doing a very steep climb) the hub runs at lower rpms at which it's output decreases. At these low speeds the drivetrain advantage of mid drives come to play, the mid drive rpm depends only on cadence hence as long as there is a gear that will keep the cadence at a level (say 60+ rpm) the motor still be in its high output and efficiency band hence will be more efficient.
In short at higher speeds hubs , very low speeds mid drives have an advantage.
An ebike will handle and steer better if the added weight of motor and battery are centered between the wheels rather than sitting on the rear wheel, which unweights the front wheel somewhat, resulting in reduced traction for steering. Rear hub motors put the weight in the wrong place for optimal bike performance.
This argument is flawed because it does not take into account the riders weight. If we were talking about mtb's this argument up to a point may have been true because on uneven terrain, the bike itself having center of gravity close to the center may help the rider to shift the center of gravity(the bike and the rider) a bit easier. When the riders want to hop, change the direction of the bike, center of gravity of the bike itself may again help.
However a rider weights usually 3 times more than the bike (sometimes much more) hence the center of gravity will be close to the rider's own. Hence geometry and riding position will be the dominating factors here and one can not suggest that steering will be better for a mid drive on smoother terrain. Since the power is transmitted via the rear wheel one may even argue that the increased weight will improve traction on the rear wheel.
More importantly, it is possible to achieve a good weight distribution with hub motors too. The placement of the heavy battery enables the manufacturer to play with the weight distribution significantly. As a matter of fact Stromer has excellent steering characteristics, on the road it is significantly better than my mid drives. And this is not only my opinion, each one of my friends had the same conclusion.
Rear motor setups are quite a bit less complicated and less costly.
Completely false.
As a matter of fact high quality hub setups like Stromer are more complicated and more costly. With a mid drive everything is enclosed(controller, sensor and the motor) in the same place and it is easy for a bike manufacturer to design the frame. The only necessities are compatible housing for the motor to be welded in the place of the bottom bracket and down tube enlarged to accommodate the battery.
On the other hand, the motor on Stromer for example is completely separated from the controller and torque sensor. So the frame has to be designed to accommodate the tmm sensor, cable integration is quite a bit more complicated and the controller is custom designed to fit the down tube.
Unfortunately comments like these are from lack of knowledge, experience and unjustified bias from what people read on the forums.