# Shimano E8000 powering down under load



## mtnbkrmike (Mar 26, 2015)

Anyone experience this?

I was hammering pretty hard (for me) earlier today and while I was laying the power down climbing or on the flats, the motor would power off and on. Didn’t matter if it was in Eco or Trail mode. It happened with higher cadence and torque. There would be a second or two of feeling like I was in quicksand before it powered back on.

Hoping I am not entering some kind of mechanical downward spiral with this e-bike.


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## PierreR (May 17, 2012)

There are a number of reasons you might be experiencing this. You may be hitting thermal overload in the motor and the controller is protecting the motor core. Another possibility is a loose connection to one of the sensors or a loose sensor itself. Most likely sensor is the brake sensors followed by the torque sensor. If it happens when you first start out a ride and the bike is cold I would suspect the sensor problem but if you have been hammering for a while, I would suspect the thermal overload protection. Last but least likely is the controller itself might be going bad.
Being very aware of what you are doing at the time of the problem can go a long ways to solving this. What are you doing with your hands. Are you riding the brake levers very softly? Are you really torqueing the pedals? Were you climbing at high power slowly? Are your screen readouts normal or giving some type of signal? Are you getting a diagnostic code? That type of thing.


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## mtnbkrmike (Mar 26, 2015)

PierreR said:


> There are a number of reasons you might be experiencing this. You may be hitting thermal overload in the motor and the controller is protecting the motor core. Another possibility is a loose connection to one of the sensors or a loose sensor itself. Most likely sensor is the brake sensors followed by the torque sensor. If it happens when you first start out a ride and the bike is cold I would suspect the sensor problem but if you have been hammering for a while, I would suspect the thermal overload protection. Last but least likely is the controller itself might be going bad.
> Being very aware of what you are doing at the time of the problem can go a long ways to solving this. What are you doing with your hands. Are you riding the brake levers very softly? Are you really torqueing the pedals? Were you climbing at high power slowly? That type of thing.


Thank you for your help. I super appreciate it.

Yesterday it was about zero C or 32 F. I had been riding for about a half hour before I noticed it. No brake pressure at the time - fingers not on the levers at all. It only happened in high cadence, balls to the wall hammering. I first noticed it climbing up a series of snow drifts. When it happened the first time, it startled me, since it felt like the bike got stuck in what felt like quicksand.

I am an undiagnosed Covid sufferer (test mid Oct came back negative, despite mid 80s O2 sats, chest pain, extreme random SOB episodes, extreme fatigue, joint pain, chest congestion, prolonged cold symptoms, etc.). Yesterday was the first day since September that I was able to really rip for sustained periods. I just got the bikes in November. It may have been happening since day 1 since it was only yesterday that I could really hammer on it, although I highly doubt it (a couple of my buddies ripped it pretty hard and were thoroughly impressed; I did too when I could, and never noticed anything).

This continued the whole ride - approximately 3 hours.

This is a total downer. I just went through weeks of trying to diagnose a mystery noise in my daughter's bike (both are Norco VLT 1s). If it's not one thing, it's another.

I think I'm going to bring it to the LBS today and let them run some diagnostics on it.

I have to say though - this bike rips. I am still in awe how fast I did some reasonably long and technical ungroomed trails yesterday. I hope I can get this resolved fairly quickly, and without all the drama we went through with my daughter's bike.

From yesterday:


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## PierreR (May 17, 2012)

There is one other possibility and this is very likely to be your problem. Depending on battery size you may be experiencing battery sag to the point the battery BMS temporarily cuts the power until the battery recovers a bit. Torque takes amps and speed takes volts. This problem is going to be exasperated by the cold temperatures.
You will not find this problem with diagnostics. You said you have two bikes. Carry a spare battery and when the problem happens swap the batteries. If the problem disappears you have found the issue to be battery sag exasperated by low temps. The fix is a bigger battery or swap out for a fresh one. You can help a bit by starting with a warm battery and strapping a few chemical heat packs to it.
In essence, the chemical reactions to produce enough power for your ride cannot keep up in that size battery. Same thing happens with cordless power tools.


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## mtnbkrmike (Mar 26, 2015)

PierreR said:


> There is one other possibility and this is very likely to be your problem. Depending on battery size you may be experiencing battery sag to the point the battery BMS temporarily cuts the power until the battery recovers a bit. Torque takes amps and speed takes volts. This problem is going to be exasperated by the cold temperatures.
> You will not find this problem with diagnostics. You said you have two bikes. Carry a spare battery and when the problem happens swap the batteries. If the problem disappears you have found the issue to be battery sag exasperated by low temps. The fix is a bigger battery or swap out for a fresh one. You can help a bit by starting with a warm battery and strapping a few chemical heat packs to it.
> In essence, the chemical reactions to produce enough power for your ride cannot keep up in that size battery. Same thing happens with cordless power tools.


Thank you for wading in on this. I was hoping you would


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## PierreR (May 17, 2012)

I have solved the problem with a bigger battery and battery heat. I am more than doubling the battery size in the next couple of weeks. Going from 1,100 watt hours to 2,560 watt hours if I want it. Modular, I can take as little at 360 watt hours to the full amount on any ride. 
My choices are 360Wh, 728,Wh, 1,100Wh, 1,456Wh, 1,816Wh, 2,184Wh or 2,560Wh Great flexibility for any size trip. 
This week I have the first three choices.


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## Bikebox (Sep 30, 2020)

Are those stock tires? If not has the speedometer been calibrated for the taller tire?
Are you sure you weren't exceeding the speed that the motor shuts off at?

Sent from my SM-N960U using Tapatalk


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## mtnbkrmike (Mar 26, 2015)

Bikebox said:


> Are those stock tires? If not has the speedometer been calibrated for the taller tire?
> Are you sure you weren't exceeding the speed that the motor shuts off at?
> 
> Sent from my SM-N960U using Tapatalk


Thank you sir. Non-stock tires (studded Wrathchilds), but the same size (approx) as the stock tires (non-studded Cake Eaters).

I glanced at the speedo from time to time when this was happening. At times I was only going 10 kph or less. It was not so much the speed or even the torque, as it was the cadence.

I thought this might have been it on the trail but quickly ruled it out.

I took a day off riding yesterday and brought my bike to the LBS. They ran some diagnostics and found nothing.

Hopefully this was some freakish thing that won't resurface. I will find out soon...

Thank you everyone for trying to help me with this. I trust you guys more than anyone.


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## mtnbkrmike (Mar 26, 2015)

double post


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## shreddr (Oct 10, 2009)

Subscribe 


Sent from my iPhone using Tapatalk


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## RickBullottaPA (Mar 4, 2015)

Could just be the assist cutting off at the limit - on E8000 bikes it cuts off early (18 to 18.5 mph) and abruptly.


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## mtnbkrmike (Mar 26, 2015)

RickBullottaPA said:


> Could just be the assist cutting off at the limit - on E8000 bikes it cuts off early (18 to 18.5 mph) and abruptly.


It's doing it at significantly slower speeds. Single digit mph. For sure under 10 mph. Did it yesterday again after I had it at the shop. Now it also creaks loudly when climbing. Maybe motor mounts since they checked the torque when it was in?

My daughter's bike had problems with noises too. Thankfully those have subsided.

I think my 2 bikes are possessed. Not having a good run with them at the moment.


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## RickBullottaPA (Mar 4, 2015)

mtnbkrmike said:


> It's doing it at significantly slower speeds. Single digit mph. For sure under 10 mph. Did it yesterday again after I had it at the shop. Now it also creaks loudly when climbing. Maybe motor mounts since they checked the torque when it was in?
> 
> My daughter's bike had problems with noises too. Thankfully those have subsided.
> 
> I think my 2 bikes are possessed. Not having a good run with them at the moment.


Another thing I'd check is the alignment/location of the magnet. Maybe you're getting an intermittent signal.


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## FM (Apr 30, 2003)

One more suggestion, use the shimano app to confirm you have the most recent firmware or update if needed. This simple step resolved some error codes I was getting on my Norco VLT.

if you’re not getting error codes, thatd be really strange.


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## mtnbkrmike (Mar 26, 2015)

FM said:


> One more suggestion, use the shimano app to confirm you have the most recent firmware or update if needed. This simple step resolved some error codes I was getting on my Norco VLT.
> 
> if you're not getting error codes, thatd be really strange.


I think I may have this solved.

We have only been riding in Eco mode. In Trail mode it doesn't seem to occur. I suppose Eco mode was not designed to be used when hammering on the pedals in techy terrain.


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## mtnbkrmike (Mar 26, 2015)

I spoke too quickly. The same issue occurs in Trail as it does in Eco. 

I am probably not explaining this very well. 

The motor does not shut off (like I previously explained) as much as the power delivery is not smooth. When you hammer on the pedals, the assist comes on initially and then drops like a lead balloon until you let up on the hammering a bit. Then it comes back on and is smooth. It’s 100% hit rate. For me it’s very irritating because I see a stretch of uphill little rollers over snow drifts and I want to hit them hard. I start hammering on the pedals and boom - the assist goes from awesome to $hit just like that. My bike instantly feels like it’s in quicksand. It’s a total kock blocker to pedalling this bike hyper aggressively. 

It may just be the algorithm or something. Maybe I just don’t like the way Shimano programmed it. Maybe I just don’t like e-bikes in general. Maybe they are still a few years away from having all the kinks ironed out. 

Not sure. 

Or maybe it’s just my bike. Sigh...

Anyway, thank you everyone for trying to help me. Much appreciated.


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## CucMan (Dec 18, 2018)

mtnbkrmike said:


> I spoke too quickly. The same issue occurs in Trail as it does in Eco.
> 
> I am probably not explaining this very well.
> 
> ...


So this is totally opinion time - and based on my rides on your specific bike and a Yamaha-based Haibike.

I have experienced what you are talking about - and realized (I assume) that I was sort of negating the design a bit. In general a manufacturer has to develop an algorithm with specific targets - one of them being output level at a specific cadence.

I found the Yamaha targeted more support at a lower cadence - Shimano at a higher cadence - and although both offered quick engagement neither liked immediate transitions in cadence. My larger point being neither supported (well) my analog riding style of suddenly pinning it to get momentum up hills, tech-y bits, etc. My assumption is that when you suddenly ramp up the cadence the bike is simply saying "you got this - you don't need my help". Again, IMO, the bikes are really best used when you sort of match a gearing/cadence combo to a need - but then changing gear/cadence a bit more progressively as needed to keep a more linear flow (I call this "tractor mode").

For me this is exactly why I got into the e-bike thing. I wanted to be able to be able to put in as much total ride effort as needed and when I wanted - but avoid the (for me) totally draining "surges". Before you throw in the towel you may want to consider trying a few rides where you alter your style (even if you want the ECO full-calorie burn action) to a more linear approach.


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## mtnbkrmike (Mar 26, 2015)

CucMan said:


> So this is totally opinion time - and based on my rides on your specific bike and a Yamaha-based Haibike.
> 
> I have experienced what you are talking about - and realized (I assume) that I was sort of negating the design a bit. In general a manufacturer has to develop an algorithm with specific targets - one of them being output level at a specific cadence.
> 
> ...


I think you nailed it. Thank you for making me not feel like I am fully psychotic. My LBS is ready to have me committed. I actually wonder whether any of them are hammering as hard as I am.

Things are fine - more than fine - until you pin it. Hard. Balls to the wall. Then the motor does seem to say "you got it brother - I'm gone for a beer - be back shortly...".

I do think it's an algorithms issue.

The bike is still a blast. But it's not perfect for someone who is still into hammering on analog bikes.

I bought that bike because I thought an e-fat bike made sense. It does, but it's not perfect for guys wanting to pin it. You can, but it's a little soul sucking when the motor kinda peaces on you at the height of pedal input.

For monster trucking up the climbs though, and FAST, zero Fs given, non-pedalling descents, the thing rocks. But in the undulating single track, it gives up when you hit peak input power on the pedals.

Truly first world problems but to me, it's a little irritating.


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## 2SLOFATASS (Mar 26, 2020)

Sorry, but it is just your bike, motor brand. I "pin" it on my Bosch full suspension fat e, and no matter what the assist level, the grade, the weather, season, yada, yada, yada, the assist is always there, unless I stop peddling. It's a thing of beauty.


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## mtnbkrmike (Mar 26, 2015)

2SLOFATASS said:


> Sorry, but it is just your bike, motor brand. I "pin" it on my Bosch full suspension fat e, and no matter what the assist level, the grade, the weather, season, yada, yada, yada, the assist is always there, unless I stop peddling. It's a thing of beauty.


Username checks out. More likely the inability to hit the same levels of "pinning". Thanks though.


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## Jack7782 (Jan 1, 2009)

You may need to adjust to riding with a little less grunt and little more finesse, and call it a day. I agree that Yamaha would probably be more to your liking.


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## Varaxis (Mar 16, 2010)

Haven't heard of that happening. Can't guess what's happening.

I'll just share my own experience:

I hit my Shimano E8000's thermal overload on a 104 F / 40 C noon ride last summer, climbing up steep hills in trail/boost. It didn't throttle me down. It just beeped at me with no symptoms. I spent a whole 5 seconds letting it rest, before hitting other steep climbs. Think I had 4 separate occasions where it beeped on that single ride alone, assuming it was for thermal reasons. I was purposely trying to push the bike to that limit...

Maybe coincidence, but the motor had repeated issues after that. It randomly beeps, shows an E020 error, which then shows as an E010 error, and assist totally cuts out. I power down and power back up and it's working fine again. Doesn't happen for any reason. Sometimes it happens 2 times within 10 minutes of each other in the middle of a flat easy ride in Eco. Sometimes it happens 3 times with a bit more space between, riding up a road climb in eco. Sometimes it even shows while riding an undulating fireroad while I'm carrying a lot of speed in an easy gear. A vast majority of my rides go without it happening. Maybe 15% are interrupted by it, and I usually ride for hours per outing. It's really no big deal; it's less annoying than stopping to pull some stick/weed out of the wheel. I suppose I got good practice at restarting the motor and timing the moment that I need to unload the pedals, to allow the torque sensor to boot up properly.

I don't wash the thing. I don't turn it upside down. 8600 miles on the odometer and I've been dealing with it since maybe the 6500 mark. It's made me shop for a new ebike, but I wonder if I hit 11k by then. It's more cause everything's clapped out, than cause of the motor. Looking at a Marin Alpine Trail E2 in size S or M, which has a Shimano system.

Other issues I had:

changing rear wheel but forgetting to swap over magnet (cuts off assist near instantly)
magnet slipping (assist cuts if no speed reading)
firebolt (Di2) shifter housing popping off (tab busted from my knee hitting it, doesn't snap back on properly)
wire popping out of display unit (no perm damage, just doesn't turn on or firebolt shifter doesn't work)
losing key to battery (no reason to take it off anyways)
losing Bluetooth password (resettable by bikeshop)


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## RickBullottaPA (Mar 4, 2015)

The Shimano "dropoff" in assist is indeed steep and sucky. But it usually doesn't occur until 18-18.5 MPH (for US spec drive systems).


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## GREGD80S (Oct 7, 2021)

mtnbkrmike said:


> I think you nailed it. Thank you for making me not feel like I am fully psychotic. My LBS is ready to have me committed. I actually wonder whether any of them are hammering as hard as I am.
> 
> Things are fine - more than fine - until you pin it. Hard. Balls to the wall. Then the motor does seem to say "you got it brother - I'm gone for a beer - be back shortly...".
> 
> ...


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## GREGD80S (Oct 7, 2021)

My e8000 just started this recently. It does it only when I get down hard on my right pedal. This makes me think it is the torque sensor maybe. I have also tightened all my frame bolts and rear wheel, and also adjusted / played with magnet location. My bike has about 2500 miles. Meanwhile, my buddy who rides with me is on his 3rd motor on his Specialized.


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