Bosch is there an alternative to these motors ?

[G-Sport]

Matched as in I guess, programed to match only one motor's specific serial number or encoded something or other!

Ah I see. Yes that's really annoying.

 

[TheKaiser]

Suggest you check the IP rating of any new motor.The Bosch motor has an IP rating that makes it unsuitable for use in an off road mountain bike as it has a low resistance to the entry of water and dirt into the engine. Poor design on the part of Bosch and poor choice of engine mountain bike manufacturers as it should be accepted that the nature of the sport would mean water and mud coming into play? I would imagine any guarantees would legally be at large as the bikes and engines are not fit for purpose. Choose an engine that is waterproof!!

Yeah, I agree as from reading the many threads on here regarding motor failures, it is clear from the pics that water ingestion is the cause of the majority of them. I have not had the opportunity to examine all motors, but I have heard it said that there is a sort of universal limitation on thightness of sealing due the temperature variation that these motors see, so they need to allow air in/out to compensate for the pressure buildup/loss during use. It seems to me that if you have a motor that is hot on a climb (the highest load and therefore heat scenario), it then releases the positive pressure, and then as it cools on the descent you have a partial vacuum, so any rain or stream crossings during that period are a recipe for disaster.

It seems to me that the need for pressure release and replacement air could be achieved with some sort of bladder system inside the motor casing, or a sort of breather valve located on the motor surface that is shielded by the frame. That would allow for tighter sealing on the spinning bits of the motor and, more imporantly, would prevent a situation where there is negative pressure inside the motor casing combined with water on the spindle/seal interface. Maybe some of these motors are already doing that, and I would be curious to hear from anyone more familiar with how the different motor brands are handling this pressure variation problem.

 

[TheKaiser]

Yeah, I agree as from reading the many threads on here regarding motor failures, it is clear from the pics that water ingestion is the cause of the majority of them. I have not had the opportunity to examine all motors, but I have heard it said that there is a sort of universal limitation on thightness of sealing due the temperature variation that these motors see, so they need to allow air in/out to compensate for the pressure buildup/loss during use. It seems to me that if you have a motor that is hot on a climb (the highest load and therefore heat scenario), it then releases the positive pressure, and then as it cools on the descent you have a partial vacuum, so any rain or stream crossings during that period are a recipe for disaster.

It seems to me that the need for pressure release and replacement air could be achieved with some sort of bladder system inside the motor casing, or a sort of breather valve located on the motor surface that is shielded by the frame. That would allow for tighter sealing on the spinning bits of the motor and, more imporantly, would prevent a situation where there is negative pressure inside the motor casing combined with water on the spindle/seal interface. Maybe some of these motors are already doing that, and I would be curious to hear from anyone more familiar with how the different motor brands are handling this pressure variation problem.

Wow, I have just seen the articles about the new Aventon bike, which has a rebranded Gabao motor that is claiming...wait for it......IP67 waterproofing! That could be game changing, and is the highest I am aware of in the e-bike motor realm (please correct me if you know otherwise though). IP67 allows for up to 30min full submersion at up to 1 meter of depth, so it should be more than enough for e-bike use, whereas the other motors mentioned earlier with IP65 (or less) are only approved for splashing, mist, or low pressure spray type exposure. On top of that, Aventon is claiming full repair parts availability for BOTH the end user and their dealer network, so I am very hopefull that this could be an end to the lack of ready repairability too, all of which has me seriously excited!

 

[Ghostrider.1127]

how the power is transferred to cranks?

with 2 and half mater chain