Common rider inflicted motor failures

[Rusty]

Yes! I am bursting to say this, but I can't do this on a public forum, sorry.

*sniff*
I am really interested in your opinion about this.

 

[Bearing Man]

Got it. De-restricting does NOT increase the mechanical power output of the electric motor. That seems to be a very misunderstood fact. I have always understood the rear wheel pickup for wheel RPM is simply a switch to turn off motor support when the RPM specified is reached (which would equate to 20 mph here in the US) and what you wrote backs that up (correct?).

Now I am curious about a "tuning chip" or "app" being applied to increase the mechanical output of the motor. Is there a thread on the forum describing either of these and how they work?

Thanks for the information.

The rear wheel pickup is interpreted by wheel circumference size to give an accurate speed. It is also used for the electronics to certify that the motor is turning and the bike is in motion (hence the fault code if the motor can't see the wheel magnet). Pedal RPM or cadence is usually monitored from within the motor. Different manufacturers use different algorithms to determine when or how the motor cuts-off, but most are (or were) reliant on knowing what the rear wheel is doing.

All European, street legal, mid drive motors ridden without licence, insurance etc. are governed by law to 250W Nominal. This means they can exceed 250W but not continuously. If you could control this with an app altering the software parameters you could in theory get more power from your motor. As I said, I don't know enough about apps to comment further.

 

[Beekeeper]

In the Bosch cx motor, why are some gears metal and some plastic? Surely there is an optimum material for gears so why have both?
When I first saw plastic gears inside I was very surprised as they look quite delicate and the teeth could strip easily.
Can anyone enlighten me?

 

[Zimmerframe]

In the Bosch cx motor, why are some gears metal and some plastic? Surely there is an optimum material for gears so why have both?
When I first saw plastic gears inside I was very surprised as they look quite delicate and the teeth could strip easily.
Can anyone enlighten me?

Every motor is different. They just have tubs full of gears of different colours and different materiel's to stop the assembly staff getting bored. Some turn out really pretty.

I guess they work out the force loadings, wear rates, minimal weights and noise from the different materiel's and then someone sits down and works out all the best compromises within those criteria.

I had a petrol RC car many many years ago, that had a large plastic to small plastic gear system. The small one would regularly strip itself. I eventually "upgraded" the small one to the metal version they sold... first time out, it stripped the large plastic one.

 

[Doomanic]

Engineering plastics are surprisingly durable and often self-lubricating. They are also significantly cheaper to produce in bulk than metal gears.

 

[Mikerb]

Lighter and quieter and do not produce wear particles.

 

[Beekeeper]

Every motor is different. They just have tubs full of gears of different colours and different materiel's to stop the assembly staff getting bored. Some turn out really pretty.

I guess they work out the force loadings, wear rates, minimal weights and noise from the different materiel's and then someone sits down and works out all the best compromises within those criteria.

I had a petrol RC car many many years ago, that had a large plastic to small plastic gear system. The small one would regularly strip itself. I eventually "upgraded" the small one to the metal version they sold... first time out, it stripped the large plastic one.

Yep I also had an RC car. This had a metal gear on the motor and plastic gears for the rest. I’m just surprised that a heavy bike with all the forces and pedal strikes etc would have plastic teeth. If i took my car gearbox apart I’d be livid with rage if I saw it stuffed full of plastic toy cogs ?

 

[Beekeeper]

Lighter and quieter and do not produce wear particles.

Fair enough. I thought there would be a good reason ??

 

[RCDallas]

Blevo does not in any way change the maximum power output of the motor nor does it change anything that Specialized hasn't allowed in their motor controller software with the exception of the wheel circumference parameter (and that is eliminated in the new software) which is used to determine speed and distance traveled (wheel circumference (distance) x RPM measured by the sensor x 60 = kph). Blevo only provided for the lowering of the circumference parameter to allow for increased RPM for a given speed (25kph) in the algorithm which results in a physical speed increase. Blevo then designed into their app a function that compensates for this circumference discrepancy and displays accurate speed and distance when set properly. Specialized's issue is not with motor problems due to this manipulation but with the 25kph restriction as mandated by law. Voiding the warranty due to de-restricting is a way of enforcing the law.

Now having said that, de-restricting the speed limit will have an effect on the motor in that the power required to travel a given stretch of road/trail WILL increase due to the speed traveled and more heat WILL be generated by the motor over that same stretch, but, and this is the key point...the maximum power, and therefore the maximum heat that can be generated by the motor during that ride will not change. That limit is set by Specialized and in the latest software it is set at 20amps @ supplied voltage (which varies due to state of charge and battery health and can be more than 36VDC and producing more than 750w). The motor, and its cooling, is designed to indefinitely sustain a power output of 250w (nominal power) so anything above that will stress the motor and if sustained for long periods will generate excess heat and could do damage...which is precisely why there are temperature sensors designed into the motor to decrease power output in an effort to prevent damage.

So in the end the physics of our rides, force, distance, velocity, acceleration, speed and time will determine how much power and heat is generated but the motor's limitations (as set by the controller software) and fail safes as designed should prevent damage and premature wear and should allow us to be out and having fun on our bikes. If there are issues with failures from use within these parameters then the design is flawed and should be taken care of by the manufacturer as provided for in the warranty contract...and Specialized has been very good in this respect!

Belts disintegrating and gear or bearing damage due to heat is not acceptable and Specialized/Brose should and are being held accountable. Now water ingress...that's a different issue all together!

 

[beutelfuchs]

Please accept my apologies for wasting your time.

If we can be of any possible help with any other problems, despite our inferiority, don't hesitate to ask.

You could ask @Al Boneta @Swan or @Bryan Wells , but as I'm sure as an intelligent men you'd understand that they wouldn't be able to give that information out.

So I'm afraid you're just stuck with the Muppets or its a case of Fuchs off.

Sorry, I just wanted to see if someone could answer my actual question. I didn't intend to buy into your search for artificial internet drama. But still I am sure some are bored enough to feel entertained.