The motor drives the crank not the other way a round so how fast you go/how fast you pedal once the motor has cut out has no bearing (sic) on stress for the motor or belt. All that Al is referring to is the motor continuing to drive the crank beyond its designed cut off speed. There is of course a margin not least for EU riders given the higher cut off in the US with (presumably) the exact same motor spec; but both the belt tension and its design will be optimised for flexibility and light weight and therefore have a maximum continuous speed of rotation rating.
Common rider inflicted motor failures
- Thread starter Al Boneta
- Start date
Supratad
Well-known member
Re power washing, do you think these are people really hammering the bearings at close range, or just general use?
Where I ride, the LBS has a lower power wash specific to bikes. I’ll give the motor area a rinse over but not hold it close or in one position, so I’m hoping I’m not causing any trouble for the future.
Where I ride, the LBS has a lower power wash specific to bikes. I’ll give the motor area a rinse over but not hold it close or in one position, so I’m hoping I’m not causing any trouble for the future.
thewildblue
Active member
Correct me if Im wrong here, but on stock gearing to do over 30mph your cadence has to be really high( think on the levo 2019 comp 32mph is 150rpm), so much so that the assist from the motor is alot lower. There is more load in turbo using 1st and 2nd gear on some proper steep climbs than pedalling out in top gear. Battery usage in the real world would also reflect this scenario, the motor works harder on steep slow speed climbs than high speed blasts.
Based on my experience with my Levo Comp I can tell when the motor is delivering its assistance without working hard because under those conditions it is completely silent. So in ECO for example which I have set at 30/50 I can hear when it finds it easy to match my torque/cadence combo input. When it starts to work harder it makes a little bit of noise. If I then drop down a gear I am back to easy street. In my book if the motor sounds like it is working hard in ECO ( ie I start to climb on a single track) I have a choice. change down again which means I will go slower, input more torque which means the motor becomes louder ( working harder) or change mode to trail ( 50/100) which then is silent and feels the same as when I was on the flat in ECO. Except now there is also more headroom. Now I know some feel cheated if they are not ragging themselves but I am more interested in maintaining speed and flow at least effort ( thats what I paid £5.5k for!!). Now all of that is restricted to speeds below 25kph which for me on mostly natural forest trails is rarely a speed you can go above anyway. If you now alter the motor response such that it exceeds that speed AND you use a high torque input rather than select a lower gear or increase the mode, I can well see how a motor will be worked much harder and the belt be subject to higher RPM that it was designed to service. For me, just like in a car ( with the exception of a normally aspirated fully race tuned engine) you get better overall performance and longevity using the motor's natural torque power band than its maximum power which is always at much higher revolutions.
Just looking at your 3 motor pictures again.
Motor 1 . Pressure washer . He/she's obviously not doing a very good job, that motor's filthy ..
Motor 2 . It's lovely and clean. How long do you advise we immerse the motors for to keep them that clean ?
Motor 3 . The tension-er wheel is far closer to the crank wheel than the others. I take it that's just because of the belt looking slightly worn...... and not that it was adjusted to a higher tension.
And some serious questions ..
On the aqua-jedi motor and the u-boat commander motor, water has come into the motor housing. On aqua-jedis, it's been over a period of time and caused corrosion and the bearings are failing ? On u-boat commanders, presumably it's caused a semi-instant fail as there isn't much corrosion.
Based on the theory that most of us will try to stop our motor being immersed, but there's a chance you can ride into a wet hole or even just extensive spray (if it breaks, that could be expensive spray), could you identify the water ingress points and either ways to reduce water ingress (waterproof grease around the cranks has previously been suggested) and/or things to do after it's happened which might help the water drain out ? (leaning the bike over on it's none drive side for a long time has been suggested)
I take it there's no magic place you can clip on an air-line and pump dry air through to clear things out - and if you could - you might blast any internal grease out at the same time - causing other problems.
Motor 1 . Pressure washer . He/she's obviously not doing a very good job, that motor's filthy ..
Motor 2 . It's lovely and clean. How long do you advise we immerse the motors for to keep them that clean ?
Motor 3 . The tension-er wheel is far closer to the crank wheel than the others. I take it that's just because of the belt looking slightly worn...... and not that it was adjusted to a higher tension.
And some serious questions ..
On the aqua-jedi motor and the u-boat commander motor, water has come into the motor housing. On aqua-jedis, it's been over a period of time and caused corrosion and the bearings are failing ? On u-boat commanders, presumably it's caused a semi-instant fail as there isn't much corrosion.
Based on the theory that most of us will try to stop our motor being immersed, but there's a chance you can ride into a wet hole or even just extensive spray (if it breaks, that could be expensive spray), could you identify the water ingress points and either ways to reduce water ingress (waterproof grease around the cranks has previously been suggested) and/or things to do after it's happened which might help the water drain out ? (leaning the bike over on it's none drive side for a long time has been suggested)
I take it there's no magic place you can clip on an air-line and pump dry air through to clear things out - and if you could - you might blast any internal grease out at the same time - causing other problems.
Assuming no damage to the casing the most vulnerable areas are the crank seals. Since the crank takes the place of the bottom bracket those bearings are under a lot of lateral pressure especially from strong riders using high crank torque with low motor assist.
thats worrying.. where I live and ride there is water, lots and lots of water and i regularly cross rivers and puddles that come up to the cranks.. I thought these motors were supposed to be sealed ?
Waynemarlow
E*POWAH Elite
I think you might lack a bit of understanding how an electric motor works, its rather different than an ICE engine. Maximum torque and power are at 0 revs ( well Ok a little bit above that by a couple of RPM ). Couple that to the bio mechanics of the human leg at a high cadence being unable to exert much torque, feeding input to the torque sensor in the motor and max torque will always be at very low rpm.
Then throw in the fact that the faster the revs of the motor, the least efficient it becomes unless it is has its field windings controlled by computer ( which is the latest moves to get higher cadence such as the developers of the TSDZ2 engine have done ) then chuck in Emtb which looks at cadence and torque input to try to cheat the way us humans can't create torque at higher cadence levels, and make us believe that we are super gods that can pedal at 90rpm and still get good feedback to the motor torque sensor.
Its not simple guys, there's a whole lot of things going on in these little motors.
Waynemarlow
E*POWAH Elite
Sorry to disappoint you, even if we fit RSS rated bearings and shield them from the worst of the effects of water being chucked at small orifices ( look up how hydraulics works ) then you will get water ingress into bearings on occasion unless the manufacturers look at the way the off road motorcycles do things.
Looking at the designs shown in the photographs, there's a bit of a learning curve to go. Would I stop riding in wet conditions, nope, would I risk riding through water deeper than the motor, nope, would I jet wash around the bearings at 2200psi, nope, would I use a bit of common sense and enjoy my bike, yup.
well I agree with you, im not going to stop what im doing even if it meant replacing a motor every few years.. the MX / enduro bikes ive had have always been ok at not getting water into the gearbox or engine unless you get the water over and into the airbox.. the rest of it though, the wheels, headset etc etc are poor, I was replacing at least 4 sets of bearings and 2 sets of spacers per wheel per year..
Welshman
Well-known member
What Ebike only goes 15mph???? I have 2 here in the UK and they all go well over 15mph and none of them have been tampered or de-restricted........
Swissrider
Well-known member
Really interesting thread. In Switzerland we have a choice between Ebikes restricted to 45k (which have to be registered, have a number plate, insurance and helmet must be worn. Also, as they are technically motorised vehicles, they are not allowed off-road) and ebikes restricted to 25k. When I bought my first ebike, my LBS said the 45k bikes were aimed at commuters, riding on tarmac, who would find it a right pain cutting out at 25k and they just want to get to work or home). On the other hand, 25k bikes are for the mountains, where steep hills and typical off-road terrain would mean that one would seldom pedal more than 25k anyway. For a reason I don’t understand, the 45k bikes are much more expensive, even though they have the same engine. Clearly, and maybe unlike Brose motors, these 45k motors can cope with high pedal speeds without shredding belts. My experience after three years and about 5000k is that my LBS was right, and the only time the 25k cut out is a pain is on tarmac, and my Kenevo isn’t designed for that anyway.
On water damage, I have always felt that washing Mountain bikes usually does more damage than good and when running a hire fleet I washed as little as possible and found bearings and chains lasted much longer by washing as little as possible. If one waited for mud to dry and used a stiff brush to get rid of most of the mud, this would be good enough most of the time. With ebikes, this is even more important - if I really have to wash my bike, I just use a bucket, sponge and toothbrush. Anyway, I think a nice patina of mud on a mountain bike shows it’s being used.
On water damage, I have always felt that washing Mountain bikes usually does more damage than good and when running a hire fleet I washed as little as possible and found bearings and chains lasted much longer by washing as little as possible. If one waited for mud to dry and used a stiff brush to get rid of most of the mud, this would be good enough most of the time. With ebikes, this is even more important - if I really have to wash my bike, I just use a bucket, sponge and toothbrush. Anyway, I think a nice patina of mud on a mountain bike shows it’s being used.
I know exactly how an electric motor works but we are not using basic electric motors. We are using electric motors controlled by a software programme that uses algorithms of speed, cadence and torque to control how the available power of the motor is delivered...….that programme presumably also takes into account the manufacturer parameters that specify how quickly it is able to overcome inertia and friction as well as how quickly it is able to decay. One of the few software parameters we are given information about is the torque delivered by the motor at various crank cadences and of course cadence is itself incremental from zero to whatever max is within the capability of the rider, whilst torque could be very high at outset and even decline thereafter as momentum is gained...….or maintained, or increased. Speed is variable but starts from 0. So nothing is linear.I think you might lack a bit of understanding how an electric motor works, its rather different than an ICE engine. Maximum torque and power are at 0 revs ( well Ok a little bit above that by a couple of RPM ). Couple that to the bio mechanics of the human leg at a high cadence being unable to exert much torque, feeding input to the torque sensor in the motor and max torque will always be at very low rpm.
Then throw in the fact that the faster the revs of the motor, the least efficient it becomes unless it is has its field windings controlled by computer ( which is the latest moves to get higher cadence such as the developers of the TSDZ2 engine have done ) then chuck in Emtb which looks at cadence and torque input to try to cheat the way us humans can't create torque at higher cadence levels, and make us believe that we are super gods that can pedal at 90rpm and still get good feedback to the motor torque sensor.
Its not simple guys, there's a whole lot of things going on in these little motors.
- Thread starter
- #44
Motor 1Just looking at your 3 motor pictures again.
Motor 1 . Pressure washer . He/she's obviously not doing a very good job, that motor's filthy ..
Motor 2 . It's lovely and clean. How long do you advise we immerse the motors for to keep them that clean ?
Motor 3 . The tension-er wheel is far closer to the crank wheel than the others. I take it that's just because of the belt looking slightly worn...... and not that it was adjusted to a higher tension.
And some serious questions ..
On the aqua-jedi motor and the u-boat commander motor, water has come into the motor housing. On aqua-jedis, it's been over a period of time and caused corrosion and the bearings are failing ? On u-boat commanders, presumably it's caused a semi-instant fail as there isn't much corrosion.
Based on the theory that most of us will try to stop our motor being immersed, but there's a chance you can ride into a wet hole or even just extensive spray (if it breaks, that could be expensive spray), could you identify the water ingress points and either ways to reduce water ingress (waterproof grease around the cranks has previously been suggested) and/or things to do after it's happened which might help the water drain out ? (leaning the bike over on it's none drive side for a long time has been suggested)
I take it there's no magic place you can clip on an air-line and pump dry air through to clear things out - and if you could - you might blast any internal grease out at the same time - causing other problems.
happened over a 9 month period of time. He power washed/ jet washed it after every ride. His headset bearings looked just like ones in that motor and he had water inside his tires.
Motor 2
He rode this bike through a water crossing that was deeper than he had thought and he got stuck in 3 feet of water. I never got a straight answer as to how long it was submerged. I think it wasn’t just a quick
dip in the water, because it looks like the water came in through the bearings. You can see rust on the bearings in the photo.
Motor 3
The tensioner is closer because there is nothing left of the belt for it to tension itself against.
that must have been some power washer!
- Thread starter
- #46
He runs tubes and there was like a half a cup of water in his tires
Hydraulic tyre armour ?
wrayb
Member
I am still trying to understand why de-restricting a motor (which I will not do because my motor is new and under warranty...and on trails it is very seldom I could exceed 20mph anyway) could be causing motors to fail. As I understand it, de-restricting only allows the motor to continue providing the exact same assistance/power at speeds over the restricted limit (here in the USA 20mph). It does NOT increase the assistance/power the motor can deliver (at any speed). So...the speed of the bike (how fast the rear wheel is rotating) really has no affect on the power the motor is delivering. In other words, the motor will work just as hard when slowly ascending a long steep climb (using 100% assist, 100% power) as it would using 100%, 100% at 30 mph or whatever mph you can gear your bike to achieve. In fact, a long steep climb at a slow speed should be building more heat because there is less air moving over the bike to cool things. Why would rear wheel speed have an affect on the motor?
It seems like most of these posts imply de-restricting the motor allows the motor to produce more power (torque/hp) which, as I understand it, is NOT true. Am I correct? Has someone found a way to increase the power output of the Bros motor on a Levo? If not, the question is how is de-restricting a bike worse on the motor than long steep climbs?
I have had 2 motor failures (both warrantied by Specialized) and I have NOT used Blevo or de-restricted, or used any device/software to alter my 2019 Comp Carbon Levo. I also have never used a pressure washer (or sprayed water near my motor) or submerged the bike. Heck, I have never ridden on a really wet/muddy day. My bike is Box Stock and always has been. I am just curious about this thread because I am still wondering if anyone is truly increasing the power output of these motors, and if so, how is the modification affecting the motor.
It seems like most of these posts imply de-restricting the motor allows the motor to produce more power (torque/hp) which, as I understand it, is NOT true. Am I correct? Has someone found a way to increase the power output of the Bros motor on a Levo? If not, the question is how is de-restricting a bike worse on the motor than long steep climbs?
I have had 2 motor failures (both warrantied by Specialized) and I have NOT used Blevo or de-restricted, or used any device/software to alter my 2019 Comp Carbon Levo. I also have never used a pressure washer (or sprayed water near my motor) or submerged the bike. Heck, I have never ridden on a really wet/muddy day. My bike is Box Stock and always has been. I am just curious about this thread because I am still wondering if anyone is truly increasing the power output of these motors, and if so, how is the modification affecting the motor.
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I think you are correct. There isn't any simple way to increase the actual power of the brose motor. Potentially it is possible in some way as specialized, via firmware update, increased the power of the older motors from 16a to 20a - presumably after sufficient testing that they were happy it had no ill effect under those conditions.
I think one area where de-restriction could cause more wear is because you might be using the 100% for longer, when you hit the restrictions, the motor would come off the power, then back on again as needed. Though you could argue that coming on and off the power more frequently could cause other wear.
It is possible to tune the E8000 shimano motor beyond it's factory settings. From what I've read this can lead to sudden and premature failure. I did test mine over a couple of days with a 10% increase out of curiosity. It generally made the motor more snatchy and considerably less smooth, but didn't convert to real world performance gains, presumably because the motor is already operating efficiently within it's factory design parameters.
EugeneK35
Member
Motor and belt rpm are linked to cadence only not bike speeed?
wrayb
Member
However...when I ride at 100%, 100% on steep, tight, loose dirt, rocky, trails I never go over 20mph so the assist/power is never turned off...for a solid hour...will someone ride a de-restricted bike over 20mph for a solid hour? I doubt it. Again, rear wheel rpm really has nothing to do with motor assist/power so I don't see how de-restricting is a problem for the motor.
GrahamPaul
E*POWAH Elite World Champion
That's pretty much what I wrote in a Q&A Forum post recently. Lots of arguments back and forth, none of which totally answered your/my question, with the exception of one possible reason. You are very unlikely to be continuously pedalling uphill at maximum motor power output in Turbo mode for your 2 hour battery life. However, there's nothing to stop you on an unrestricted bike flying flat out at 45mph down a long flat gravel or asphalt road for 2 hours with the motor screaming at full power. Heat build-up in the motor would be the killer as it is just not designed for that use.
5mm Pitch HTD 5M Timing Belt 405-5M-15 Length 405 mm Width 15 mm
this is the one for the pre-2019 motors, wether its any stronger i dont know.
GrandesRoues
Member
This is wrong concerning the power.
Power is velocity × speed, so at 0 rpm the power is null.
On a synchronous motor like used on the bikes, you get maximum torque when the magnetic field of the stator is perpendicular to the one of the rotor. This is essally done with modern ESC.
GrandesRoues
Member
It does.
Power is torque × velocity.
Imagine you tune your bike to allow it to have assistance at 32km/h rather than 25km/h (by using something to fool the stock speed sensor). Comparing the 2 configurations, the motor will put out the same torque at both speed. But the deristrected bike will have a 50% greater velocity, and by the formula above, it put out more power.
Electric motors and mechanical transmission usually have 3 limits :
Power ( full throlle for long) -> overheating
Torque (max assistance) -> break
Speed -> centrifugal forces cause breaks, rotor touching the stator, vibrations...
wrayb
Member
My 500wh battery will last 1 hour at 100% 100%. That is on a trail so it is definitely on and off constantly as I cannot pedal continuously. I guess if someone could go full bore for 2 hours at 40 mph without letting up that would cook the motor. But who would ride a Levo like that? And...if I ride my bike on the same road at 19 mph for 2 hours I would be doing the same thing wouldn't I?
wrayb
Member
What velocity are you referring to? The rpm of the rear wheel? That is determined by the gear ratio. If the bike is ridden uphill in a smaller gear with the same torque wouldn't it be delivering the same power output measured at the motor?
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GrandesRoues
Member
The interest of the notion of power is that it's value is keeped through gearing (when the transmission have good efficiency).
Your gearing, and the gearing of the motor have negligible effect, and the power used is the force pushing you uphill × your linear velocity.
I suggest you look for this notion in online mechanical enginnering courses for beginners (sorry, my personnal material is not in English).
Your gearing, and the gearing of the motor have negligible effect, and the power used is the force pushing you uphill × your linear velocity.
I suggest you look for this notion in online mechanical enginnering courses for beginners (sorry, my personnal material is not in English).
I think it has to do with motor revolutions. The amount of torque/pedal assist produced by the motor is determined by the amperage it can draw from the battery...which in turn is controlled by software in line with both rider torque input and cadence. A uphill slog may draw maximum power but only if cadence is kept high because the motor revolutions can never exceed the crank revolutions...but must keep up with them. The motor and rider are however working a gainst gravity and rider/bike weight so revs at the crank will still be relatively slow and not sustained at a high rate unless of course the rider is a super human! Under those circumstances the motor may be working hard but revolutions still quite low. Convert that to on the flat and with more speed headroom ( derestricted). Inertia has been overcome and the bike has momentum. High cadence is possible over protracted periods coupled with relatively high rider torque input ( ie caning it!) and both motor power output and revolutions to the crank will be higher.
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