Levo Gen 2 real cause of motor failures?

[Cavi]

soo what are the things that they have determined to be the causes of the motor failures? I am wanting to know if I can change anything in my riding to limit the chances of motor failure

 

[Mike C]

soo what are the things that they have determined to be the causes of the motor failures? I am wanting to know if I can change anything in my riding to limit the chances of motor failure

"The motor manufacturer claims to have found the fault, and their solution is a software update that reduces certain peaks loads, putting less strain on the belt and thereby increasing its longevity. The software update shouldn’t have any negative effects on the motor’s performance. The latest motors will also come with reinforced belts and other technical improvements to improve noise reduction and durability."

 

[Al Boneta]

One of the biggest reasons the belt would fail is when a rider would be descending in the highest gear followed by an immediate climb. Riders would be in too high of a gear to make the climb and then switch to turbo mode, the belt couldn’t take the combined torque or the rider and the motor.
The other main factor is water ingress. This is usually caused by using a power washer to clean the bike

 

[DreamensioN]

Isn't it "cadence is king" too? Like if you can keep spinning the pedals at 50rpm+ (I'm usually around the 70-90rpm zone), you're lessening the torque demand of the motor, thereby increasing its longevity?

 

[urastus]

Using them is probably the one thing most failures have in common. They just aren't that reliable. It's like the motor car industry 30 or 40 years ago, or longer.

 

[wepn]

Riding in very wet conditions where water enters the motor through the crankshaft bearings is very likely a major accumulative contributor to longer term degradation and eventual failure. Pedal strikes have also been mentioned as a major contributor, either immediate or accumulative, that isn't clear.

 

[Al Boneta]

I did a whole thread on this already it was about the first gen Levo motor but it still applies Common rider inflicted motor failures - EMTB Forums

 

[wepn]

I did a whole thread on this already it was about the first gen Levo motor but it still applies Common rider inflicted motor failures - EMTB Forums

A lot of very good relevant information there.

Makes me wonder, are riding in the wet - and pedal strikes - causes of rider induced failure? That's debatable but very feasible beyond a certain point I guess.

 

[Al Boneta]

A lot of very good relevant information there.

Makes me wonder, are riding in the wet - and pedal strikes - causes of rider induced failure? That's debatable but very feasible beyond a certain point I guess.

Pedal strikes are not a contributing factor to motor failure. The crank arm will bend before the main shaft in the motor.
Riding in wet can cause some water ingress, but no where near the same level a high stream of water directed at the main bearings or the hole under the top where the rear brake hose, dropper cable, TCU wire and derailleur cable come out.

I’m not going to even touch on motor derestriction

 

[wepn]

Pedal strikes are not a contributing factor to motor failure. The crank arm will bend before the main shaft in the motor.
Riding in wet can cause some water ingress, but no where near the same level a high stream of water directed at the main bearings or the hole under the top where the rear brake hose, dropper cable, TCU wire and derailleur cable come out.

That was not my opinion but from somebody who fixes them & obviously knows them well.

[+] I seem to recall that Bearing Man has noted that damage may be due to the high impact forces transmitted through the crankshaft, not necessarily damage to the crankshaft itself. Or at least that's what I recall. I could be wrong.

[++] I have a Kenevo that's been ridden in the rain and suffered some pedal strikes and it is still faultless. Best bike ever.

[+++] All my pedal strikes were on my 1st day on the bike and there were a few heavy ones.

[++++] I tried out un-neutered walk-mode again today & realised it could possibly help avoid pedal strikes, albeit only low speed strikes. Walk-mode is a little too fast for walking the bike so that was probably the motivation. Couldn't possibly be a Nanny EC directive could it? The logical solution for me would be to have a toggle in Mission Control to switch between trail low speed as it was & a ramped not delayed actual walk-mode.

I have done posts before regards pedal strikes. This is a major contributor i believe, but not the only reason. There is no change to the clutch and I believe the belt is still carbon but a few more strands thicker.

 

[Mikerb]

Whilst not disputing anything @Al Boneta has posted, I understood that a primary cause of failure ( other than water ingress) was caused by continuous use of high power modes at low cadence ( ie in a high gear) causing heat build up in the sprag clutch bearing which in turn produces high levels of friction. End result being destruction of that bearing and/or belt and/or sprag clutch. Both that bearing and the belt have been replaced with upgraded items. The very short term "spikes" found in the previous firmware version presumably added to the problem. So the recommendation was to maintain a higher than normal ( normal as in analogue bike) cadence especially in higher power modes and when climbing.

 

[Al Boneta]

Isn't it "cadence is king" too? Like if you can keep spinning the pedals at 50rpm+ (I'm usually around the 70-90rpm zone), you're lessening the torque demand of the motor, thereby increasing its longevity?

80-90 is ideal and also when the motor works most efficiently.
The rider also gets more aerobic benefit at this cadence.

Whilst not disputing anything @Al Boneta has posted, I understood that a primary cause of failure ( other than water ingress) was caused by continuous use of high power modes at low cadence ( ie in a high gear) causing heat build up in the sprag clutch bearing which in turn produces high levels of friction. End result being destruction of that bearing and/or belt and/or sprag clutch. Both that bearing and the belt have been replaced with upgraded items. The very short term "spikes" found in the previous firmware version presumably added to the problem. So the recommendation was to maintain a higher than normal ( normal as in analogue bike) cadence especially in higher power modes and when climbing.

I mentioned the use of high power, high gear while climbing causing belt failure in my first post

 

[Bearing Man]

The sprag bearings are locked and not dragging or slipping while riding (unless damaged) Therefore they will not suffer from full power or high speed riding. Their name of "clutch" bearing, is technically wrong.
Shocks to this bearing cause the small interconnecting parts of the bearing cage to fail, when these fail they allow the sprags to flip over and lay down flat (this is the cracking and popping that a lot of people report) It it the beginning of the end for this bearing. Once enough of these sprags lay down, the bearing will then start to jump or slip, this is then the end.

 

[Mikerb]

The sprag bearings are locked and not dragging or slipping while riding (unless damaged) Therefore they will not suffer from full power or high speed riding. Their name of "clutch" bearing, is technically wrong.
Shocks to this bearing cause the small interconnecting parts of the bearing cage to fail, when these fail they allow the sprags to flip over and lay down flat (this is the cracking and popping that a lot of people report) It it the beginning of the end for this bearing. Once enough of these sprags lay down, the bearing will then start to jump or slip, this is then the end.

Yes I agree...the equivalent of a Jack Knight as opposed to Salisbury limited slip differential for those that have raced Stocks or Rally cars!!

 

[Mikerb]

80-90 is ideal and also when the motor works most efficiently.
The rider also gets more aerobic benefit at this cadence.

I mentioned the use of high power, high gear while climbing causing belt failure in my first post

Ah..sorry...missed that....but the recent info from Spesh confirmed that this was the primary thing identified when warranty return motors were examined ......so just affirmation of your statement.

 

[Konanige]

So the causes are being a lazy git and turboing everywhere, and not learning to ride your bike and twatting the pedals left right and centre!!????‍

 

[Troutwrestler]

There is more to it than this. The Sprag bearings are rated to 250nm. The motor can output 90nm, but what about the rider? Pro riders have been shown to output 260nm of torque. This alone would damage the sprag bearing, without the additional load of the motor, but realistically most of us are not putting out 260nm, but we'd only need to put out 160nm to reach the limit of the sprag bearing.

However, this is still not it. Another factor is the huge loads that can be put on the sprag bearings via chain growth as the suspension compresses in a positive G-out situation. The bottom of Caddon Bank at Inners would be a good example. The motor is working, the rider is hammering, and the suspension is compressing putting significant loads through the chain to the chainring which although it is tension in the chain, it manifests itself as torque on the sprag bearing. This load, plus the motor output, plus the rider input is what is damaging the sprag bearings. I bet the motor failures on Levo HTs are proportionally MUCH lower than on FSRs.

The software update to the 2.1 motors is meant to address this. I would like to know why a similar firmware update isn't available for the 1.3 motor? I am on my 3rd, and I think (judging by the noises from the motor) I am heading rapidly for the 4th.

Pedal strikes will not be good. Pressure washing will not be good. Submerging in water will not be good. Riding in Turbo everywhere would not be good (although I can't understand why people actually do this).

I know not to crank it in a stupid high gear, and aim to spin as much as possible at 90rpm, I have minimal pedal strikes, I have only washed the latest motor twice, and only with a brush and bucket, I certainly haven't submerged it, and I rarely use turbo - the Mission Control logs will show this - so why is my 3rd (!) motor failing? I think the answer is to do with the sum of motor+rider+suspension generated loads.

 

[High Rock Ruti]

High Rock Rock

Leading cause of motor failure is USE, your not supposed to RIDE your bike.

Four motor failures in Iess than a thousand total miles 3 belts 1 clutch, full refund, no more Brose failures.

THE MOTORS ARE DEFECTIVE.

By the way a software fix for a mechanical problem, is way to compensate for, wait for it....
A DEFECTIVE MOTOR.

 

[Troutwrestler]

TBH, my 3rd motor is making popping and pinging noises, that sound like a poorly engaged freehub, but are definitely coming from the motor itself. It even does it in walk mode. When it finally fails I will be pursuing a proportional refund under the Consumer Rights Act from the supplying dealer. I don't expect it to be easy, but I do expect to be successful as the law is on my side and I am not a quitter or a pushover.

 

[naharris212]

I spoken to a handful of mechanics and do a fair amount of mechanical stuff myself. I’ve blown two belts, my dad one belt and my brother another belt. Not all levo’s but all Brose mag s. I just got my bike back, Brose and other companies that have written their own firmware like specialized have addressed the issues at hand (hopefull they work ). 1. All new replacement belts come with a reinforced carbon strip. <—— so belts are much stronger and hopefully won’t shred like before. 2. An issue where the motor would blast 100% power at in opportune times possibly making heavy wear on said belt has also been fixed.

There are a few YouTube videos online showing how to swap the belt. You can get em for like $30 and it takes 5 mins. Unfortunately it would break the warranty but considering most bikes are in the shop for 2 months needed a $30 belt, is it worth it?

 

[Troutwrestler]

I don't think I have had any belt failures and so far the belt hasn't been the issue for me. It has been the Sprag bearings every time. I think the belts only go through derestricting/ Turbo all the time, and I'm neither.

 

[Mikerb]

Mmm...except only Spesh and Brose know what faults there are in warranty returned motors and despite lots of riders and lbs speculating that a broken belt was the problem Spesh have said that is not what is found in the majority of cases. It is also a conundrum that given the volume of Levos sold the warranty rate is/ was not excessive overall meaning that the majority of riders have not experienced problems. The key area of potential failure given either specific rider use or environment was found to be the sprag bearing.....with possible consequential damage to the belt.

 

[Bearing Man]

Spesh, Brose and us at Performance Line Bearings see all the issues. We repair 20 to 30 Brose motors a month from all over the world, dry climates, wet climates, hot climates, cold climates, mountain regions, desert regions and everything in between. We know exactly what fails and why it does it. I have posted many times on forums what causes this issue or that, but soon the post sinks below the waves of speculation. So, this post is a little different.

I’m not saying that Brose or any other motor don’t have issues, but I am saying it's not always the motors fault. The photo below is what many people, including dealers and owners never get to see.
Unfortunately, we see 2 or 3 of these a week. The owner was totally unaware that there was anything wrong with the motor. they reported that the motor still worked but the crank was just a little stiff. Adamant that his motor had never been pressure washed or dropped in the sea for a few weeks.

I guess what I’m trying to say. Sometimes, indeed, quite often, it’s not always a parts failure you’re reading about when someone’s posting that their motor has failed again!. There are many different reasons for motor failure. It’s actually testament to some of these motors that they are still running in such a condition as the one below.

I can also assure you all that some big changes have been made in the very latest motors (apart from the belt) and we will be doing a video on this a little later in the year.

Just for clarity, the current thicker belt is the same material as the old belt. There is no new carbon fibre strip, or Kevlar strands or space dust etc. It is a carbon fibre strand belt that is slightly thicker because it has a few more strands and therefor a little stronger.

 

[wepn]

The owner was totally unaware that there was anything wrong with the motor. they reported that the motor still worked but the crank was just a little stiff. Adamant that his motor had never been pressure washed or dropped in the sea for a few weeks.

Thank you Bearing Man. Your knowledge & experience is greatly appreciated, confirmed by all the unanimous positive reactions.

My bike has been fault free & fantastic but I think your point raises very important considerations.

My bike has never been pressure washed, never dropped in the sea for a few weeks or at all. It has been ridden normally with only a few instances of riding in marginally wet conditions. I'd be just as adamant as that owner. So potentially my motor could have - or may develop - similar internal water & debris entry.

It's well established that this can occur through the spaces around the crankshaft bearings. This is especially visible if you look behind the chainwheel. The best way to understand the issue is to study all the detail in Bearing Man's video.

Velolab & Bearing Man - Performanceline Bearings - have MudStop 2.0 for Bosch motors though unfortunately not for Brose. It looks like the cover doesn't need to be removed for Bosch installations. It's not clear if the cover would need to be removed for installation of similar MudStop for Brose installations. If so, that would be problematic on Specialized bikes with since opening the motor voids the warranty.

On an expensive bike like the Levo or Kenevo - any bike for that matter - every customer without exception would want trouble free operation way beyond the 2 year warranty period.

There have been several previous official OEM revision kits distributed for waterproofing & pivot fastening.

My question to Specialized:

Do you intend to distribute a similar kit in order to prevent what happened to that customer's motor in the photo above?

If not, are you able to provide dimensions & diagram of each version of affected motors so that the MudStop type solution could be printed by customers or otherwise provided by 3rd parties?

I know Spesh are special so I have no doubt there'll be a considered & effective solution some time soon.