Opinions on reliability of Impulse 2 motor and Nexus gears

[ebike152]

Hi, I tested a Kalkhoff Agattu recently and was very impressed,however before I spend nearly 3 grand I'd be grateful for experiences of long tern reliability.
I'm disappointed that there is only a 2year warranty on such a premium bike as I would expect to get at least 5 years normal usage for such a large outlay. If Kalkhoff would offer to replace a failed motor in years 3-5 for a fixed price of ,say £300,I'd be on the next train to 50 Cycles showroom. At the moment I'm hesitating.

 

[KeithMac]

Have a good long search before you make your mind up.

There was a database on a German site iirc and it didn't make good reading.

 

[nemesis]

Hi, I tested a Kalkhoff Agattu recently and was very impressed,however before I spend nearly 3 grand I'd be grateful for experiences of long tern reliability.
I'm disappointed that there is only a 2year warranty on such a premium bike as I would expect to get at least 5 years normal usage for such a large outlay. If Kalkhoff would offer to replace a failed motor in years 3-5 for a fixed price of ,say £300,I'd be on the next train to 50 Cycles showroom. At the moment I'm hesitating.

The reliability of the impulse motor is well documented on this forum.I have had three motor replacements on two bikes including the latest 2016 evo version.
I have been riding the Bosch CX motor in a Cube bike for five months every day and it has been flawless,nice smooth power that builds as it goes faster.

 

[flecc]

The Impulse 2 has been so troublesome that the makers now renew the two year warranty each time a motor fails and has to be changed.

However, we don't know how long that will last and who wants the hassle of a failing motor anyway?

Currently the motor has been changed to the Evo, but being new we don't know how reliable that will be.

The Nexus 8 in both forms has been very reliable, but the newer 14 gear model has been troublesome for many. The Nexus 7 still exists but is an older less efficient design.
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[IR772]

At the moment I'm hesitating.

Stay that way until you have done a lot of reading.

One thread on the faulty Kalkoff engine is 24 pages long!!!!!!

 

[Crockers]

50 cycles used to sell just Kalkhoff bikes....I've noticed they now sell other brands too. Giant, Scott.
Are they worried about the rep of that impulse motor???? Make your own judgement.

 

[RobF]

Hi, I tested a Kalkhoff Agattu recently and was very impressed,however before I spend nearly 3 grand I'd be grateful for experiences of long tern reliability.
I'm disappointed that there is only a 2year warranty on such a premium bike as I would expect to get at least 5 years normal usage for such a large outlay. If Kalkhoff would offer to replace a failed motor in years 3-5 for a fixed price of ,say £300,I'd be on the next train to 50 Cycles showroom. At the moment I'm hesitating.

Difficult to assess the reliability of the Impulse/Evo motor from posts on the internet.

But the number of disgruntled owners is too big to ignore, seems daft to me to take the risk on a Kalkhoff bike when there are alternatives.

Kalkhoffs are good quality German roadsters/trekking bikes with a crank assist system that is good to use - when it works.

Lots of other makes offers similar quality and types of ebikes with the Bosch or Yamaha system, both of which ride nicely and both are a lot more reliable than Impulse/Evo.

One advantage of Kalkhoffs is some are available with large capacity batteries.

That's less of an edge now you can get Bosch - and the latest Yamaha - bikes with 500wh batteries.

 

[Crockers]

Or a Bulls Brose with 600wh

 

[ebike152]

Thank you all for your replies,you've convinced me that I need to do further research. The Kalkhoff Agattu was a lovely bike and 50Cycles were very helpful but I'm now going to look at Bosch and Yamaha bikes.

 

[ebike152]

I've just found a Dutch pedelecs forum and the first post I read was from a very dissatisfied Kalkhoff owner who is now on his fourth motor in 5000 miles!

 

[flecc]

I've just found a Dutch pedelecs forum and the first post I read was from a very dissatisfied Kalkhoff owner who is now on his fourth motor in 5000 miles!

I'm not surprised. Daum, who designed the Impulse motor and make it for Kalkhoff really need to get a grip on this, continuously replacing under warranty isn't good enough.

They need to redesign the unit, including making the failing nylon gear stronger, and then replace warranty failures with the redesigned one. And if they can't afford to do that as the small company they are, then negotiate some support from Derby Cycles gmbh who own Kalkhoff and are the second largest bicycle manufacturing group in Europe and one of the largest in the world.
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[USAebike]

I’m not saying nobody’s has had problems with these motors. Play some people bypass the safeties with chips and go faster than they should be. I can’t tell you a guy trust very well sold 25 bikes with this motor. out of 25 one had a bad motor. Blames. that one had a mechanic who didn’t know what he was doing.

these rotors are very easy to rebuild and their services that rebuild them in the United States for $300. Nothing is perfect and everything breaks eventually

 

[USAebike]

I'm not surprised. Daum, who designed the Impulse motor and make it for Kalkhoff really need to get a grip on this, continuously replacing under warranty isn't good enough.

They need to redesign the unit, including making the failing nylon gear stronger, and then replace warranty failures with the redesigned one. And if they can't afford to do that as the small company they are, then negotiate some support from Derby Cycles gmbh who own Kalkhoff and are the second largest bicycle manufacturing group in Europe and one of the largest in the world.
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My Impulse 2 Motor started making noise the other day. It appears that very little grease was put on a needle bearing. Infect a bearing was like gummy. additionally , the type of lubricant they put on these little metal parts, that allow you to backpedal with the motor on. Had a wrong type of grease and were oxidized and sticky. Cleaned all the parts put some good white lubricant grease.

The motor is now good as new. It looks like these motors are fine if they were assembled properly in the factory. I also bought a spare motor brand new and just did the same service to it.

we’ll see I’m gonna try to get 5000 miles on this bike. They can give you six brand new motors, if they use that poor choice for lubricant you’ll have problems six times.

 

[AntonyC]

The ergonomics sold me on an Agattu and I bought a used one with a newly fitted Impulse 2 motor. 1800 miles later the motor's toast but the battery is still good at 9 years of age, the overbuilt frame barely notices 35kg luggage and it's been a great intro to riding MTB trails. There's a fine bike struggling to emerge here and if I could rewind I'd get the pedal-only Agattu and a torquey motor.

 

[flecc]

The ergonomics sold me on an Agattu and I bought a used one with a newly fitted Impulse 2 motor. 1800 miles later the motor's toast but the battery is still good at 9 years of age, the overbuilt frame barely notices 35kg luggage and it's been a great intro to riding MTB trails. There's a fine bike struggling to emerge here and if I could rewind I'd get the pedal-only Agattu and a torquey motor.

Completely agree. I was one of the two original reviewers of the assisted Agattu when it was introduced here in late 2007 and reviewed it very favourably, particularly praising many of the bike's aspects. That was when it had the very reliable Panasonic motor and numerous sales resulted from the reviews.

Their switch to the Daum motor, branded Impulse, was initially ok but for a software peculiarity that meant they started with full power which after a few seconds reduced. Customers didn't like that and complained so an update was introduced to maintain the power. That was the beginning of the troubles, making it clear its design strength was inadequate in some respects.

Then with competition from Bosch with more power, Kalkhoff-Daum entered into a power race with Bosch by introducing the Impulse 2. The result was that almost every motor failed and Daum had no answers, eventually introducing a revised model called Evo, but that was also failing. A rolling two year warranty maintained some sales for a while, but eventually prospective customers gave up buying. The Kalkhoff importer here failed and went out of business later, swamped by the strain of dealing with huge numbers of dissatisfied customers.

Referencing USAe-bike's post , it is not a grease problem. We've had a whole decade's experience with the Impulse motors amd it's clear their mechanical design was inadequate for the increases in power applied later. The pawls don't shatter from a grease problem for example, they break up because they are simply not strong enough.

As the old saying goes, "One swallow doth not a Summer make", so the odd incidence of someone having a reliable Impulse short term does not in any way offset the countless hundreds which have failed within 2000 miles.
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[USAebike]

Completely agree. I was one of the two original reviewers of the assisted Agattu when it was introduced here in late 2007 and reviewed it very favourably, particularly praising many of the bike's aspects. That was when it had the very reliable Panasonic motor and numerous sales resulted from the reviews.

Their switch to the Daum motor, branded Impulse, was initially ok but for a software peculiarity that meant they started with full power which after a few seconds reduced. Customers didn't like that and complained so an update was introduced to maintain the power. That was the beginning of the troubles, making it clear its design strength was inadequate in some respects.

Then with competition from Bosch with more power, Kalkhoff-Daum entered into a power race with Bosch by introducing the Impulse 2. The result was that almost every motor failed and Daum had no answers, eventually introducing a revised model called Evo, but that was also failing. A rolling two year warranty maintained some sales for a while, but eventually prospective customers gave up buying. The Kalkhoff importer here failed and went out of business later, swamped by the strain of dealing with huge numbers of dissatisfied customers.

Referencing USAe-bike's post , it is not a grease problem. We've had a whole decade's experience with the Impulse motors amd it's clear their mechanical design was inadequate for the increases in power applied later. The pawls don't shatter from a grease problem for example, they break up because they are simply not strong enough.

As the old saying goes, "One swallow doth not a Summer make", so the odd incidence of someone having a reliable Impulse short term does not in any way offset the countless hundreds which have failed within 2000 miles.
.

Reason these are failing is because the factory used the wrong type of grease. Mine failed at 230 miles. I pulled the motor, cleaned and lubricated the bearing and the motor pawls. (not sure the correct word). Put it back together and it us like new. Of course that doesn’t help the people who don’t know how to work on their own bikes. Kalkhoff just changes motors and put motors at work assembled improperly back in. But Sadly nobody’s still getting up and realize the cause in prevented it. There’s a video on this on YouTube it’s very simple if you own one. I have a back up motor and have ready on the service on it. This motor will not fail for a long time.

I took one apart that was brand new and found the same crappy gummy lubricant used. Clean and lubricated properly it will last a long time. I’m actually a person who’s taken the motors apart and look at them not guessing.

My background is mechanical engineer. I know what I am talking about.

And yes the motor pawls break because of the grease problem. When they’re not lubricated properly they get stickey and get stuck either up or down. When it gets stuck up they get caught and can easily crack. When they are lubricated properly they move back down. It’s a very simple system that works well if properly lubricated. Most of these motors were probably doomed from the day to come out of the factory.

 

[flecc]

Reason these are failing is because the factory used the wrong type of grease.

It strikes as ridiculous to suggest that Daum at no time during the years of these problems did not realise they were using the wrong grease.

However, that is besides the point, which is that these Impulse 2 motors were not fit for purpose as supplied, which is all that matters. Over 95% of the buyers will not be mechanical engineers, not should customers have been expected to undertake premature repairs.

Kalkhoff realised this years ago so stopped fitting the Daum sourced motors, fitting various others for a short while and latterly only Bosch units. Despite the Bosch units also experiencing a few problems, using them has proved a far wiser choice for both Kalkhoff and their customers.
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[USAebike]

It strikes as ridiculous to suggest that Daum at no time during the years of these problems did not realise they were using the wrong grease.

However, that is besides the point, which is that these Impulse 2 motors were not fit for purpose as supplied, which is all that matters. Over 95% of the buyers will not be mechanical engineers, not should customers have been expected to undertake premature repairs.

Kalkhoff realised this years ago so stopped fitting the Daum sourced motors, fitting various others for a short while and latterly only Bosch units. Despite the Bosch units also experiencing a few problems, using them has proved a far wiser choice for both Kalkhoff and their customers.
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whether you might find this ridiculous or not. It is however a fact. The Bosch motors are plastic and they will break. And they are expensive to repair. No Electric bike dealer in the UK went out if business because of warranty issues Of this motor. They were paid by kalkhoff. The point of my post is to help people who currently own a bike with this motor. I’m not saying it’s a better motor than the Bosch. The owners who already own this motor, need a solution better than the ones I read from you. That’s what I’m trying to provide.

 

[flecc]

No Electric bike dealer in the UK went out if business because of warranty issues Of this motor. They were paid by kalkhoff.

Untrue, don't speak of things you know nothing about. The UK agent 50cycles eventually ceased trading because customers no longer trusted them or Kalkhoff. Customers patience was exhausted by the repeated motor replacements, as many as five in a few cases. The responses to the troubles from Kalkhoff and Daum and thus 50cycles were wholly inadequate for a very long time.

I don't agree that the whole of the trouble was down to the grease used. If that had been the case that very minor and obvious engineering problem would have been quickly solved and there would still be new e-bikes using these Daum motors.
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[cyclebuddy]

@USAebike seems to be saying that Kalkhoff, who purchased Daum at significant cost, and then, after trying a few iterations/modifications to try and make it workable/competitive with other motor manufacturers of the time, failed so badly they themselves chose to abandon it completely and use third party motors instead.

And @USAebike is saying that's just down to the grease they used? Yeah, right.

I doubt the UK distributer for Kalkhoff, who went bust (they claim) on the back of it, would agree.