Ouch! Just sheared my Crystalyte freewheel off.

[adrian_sm]

Okay. I am writing this on the side of the road while I wait to be picked up. A few scraps, bruises , bit of blood but nothing major.

I was on my daily commute in to work. Enjoying the ride on a cool crisp day. Just pulled in behind a few cars in a turn right only lane at some lights. Light goes green. I stand up on the pedals and start to accelerate away trying not to be too slow as I don't want to miss the light change. Suddenly something gives way, I hit the deck hard mainly with my elbow wondering what the hell happened. Quickly try and pick myself and bike up off the road so I don't get run over.

Time to assess the damage and see what caused things. Chain is off the gears, maybe it just jumped. Put it back on. Go to test it. Hang on the cassette is spinning but the wheel isn't. The screw mount for the freewheel has just sheared off. Arghhhhhh.

Pretty sure that mounts one of the hub bearings. So I ain't going nowhere under my own steam. And work is still 6 kms away. That is a long walk.....

Bugger time to call the support crew.

 

[Sacman]

Okay. I am writing this on the side of the road while I wait to be picked up. A few scraps, bruises , bit of blood but nothing major.

I was on my daily commute in to work. Enjoying the ride on a cool crisp day. Just pulled in behind a few cars in a turn right only lane at some lights. Light goes green. I stand up on the pedals and start to accelerate away trying not to be too slow as I don't want to miss the light change. Suddenly something gives way, I hit the deck hard mainly with my elbow wondering what the hell happened. Quickly try and pick myself and bike up off the road so I don't get run over.

Time to assess the damage and see what caused things. Chain is off the gears, maybe it just jumped. Put it back on. Go to test it. Hang on the cassette is spinning but the wheel isn't. The screw mount for the freewheel has just sheared off. Arghhhhhh.

Pretty sure that mounts one of the hub bearings. So I ain't going nowhere under my own steam. And work is still 6 kms away. That is a long walk.....

Bugger time to call the support crew.

Hey Adrian the same thing happened to me almost 2 years ago. Check my post here http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=6995 Nothing to do but to buy another threaded side cover. Crystalyte now makes threaded side covers that are reinforced with a steel collar and flange. So it is much stronger.

 

[morph999]

sorry about your luck. I've never had anything break on my electric bike yet. I guess i've been lucky.

 

[adrian_sm]

Thanks guys. I should be able to get a replacement side cover from where I bought the motor. Hopefully it is one of the new reinforced steel ones.

The things that annoys me the most is that I had to drive in to work.The bike has been running perfectly without missing a beat. I have now done about 1700kms, with my daily ride to and from work, even with crappy winter weather in Melbourne. Last year without the ebike, I would be lucky if I rode 3 days a week, even when the weather was perfect.

Now I have broken a 6 week streak of commuting via the bike. It actaully feels weird driving the car.

 

[BiGH]

sorry to hear this. hope you can sort it out fast.

 

[HighTekBikes]

To repair a hub with stripped threads (for the freewheel), go to your local auto supply and pick up a tube of JB-weld metal glue. Remove the motor and take off the freewheel. Follow the instructions to blend the two glue parts together. Clean the threads of metal bits and oil. Coat the threads on the motor lightly with the JB-weld and screw the freewheel back on. Allow it to set before applying pressure.

 

[TylerDurden]

They break.

Like this:

and this:

I suspect it's due to off-axis torque from imprecise cover production. I don't think the freewheel itself or the load on the freewheel is much factor at all, rather the cover's alignment to the axle. (Just my opinion.)

 

[gogo]

@ HTB_Terry, If you are suggesting a fix for stripped freewheel mounting threads of the hub motor, I agree that JB weld between clean freewheel threads and the stripped hub threads would probably work.

If you follow the link from Sacman in the second post, I don't think JB weld would work there. I'm not sure which condition adrian_sm is describing.

 

[adrian_sm]

I haven't taken photos yet, but it looks just like this one, except mine appears to have sealed bearings.:

I doubt there is enough wall section to provide enough strength for the JBWeld solution.

For those of you that have replaced the side-cover with a new one, have they held up alright. Do with think it was more dodgy casting, causing mice little stress concentrators? Or was it due to misalignment int he rest of the motor, so I can expect it to happen again. I really don't want this to happen again. I have been treating the bike really well, just riding on normal roads, never jump curbs, never taken it off-road, avoid pot holes, I only weigh about 78kg. There is no way I could change my riding style to go easier on it. If it is likely to happen again, I would prefer spending some extra cash and going for something of higher quality.

It definitely wiped my smug ev-grin off my face, when I am lying in the middle of the road bleeding, then not even being able to pedal home.

The guy I bought it off is ordering new side covers, but they are a week or two away. So I will be stripping the bike back to it's original glory and flying solo.

So has it happened again to anyone? Or does it look like a more random failure?

 

[voicecoils]

Did you get your 408 from John @ EMTB ? He should be able to sort you out with the reinforced sidecovers.

I have seen a few forum posts about sidecover issues but I think E-S posts tend to come up when things go wrong rather then posts about how well things are going. Hopefully the new sidecovers will bring what I think is a small failure rate down closer to zero.

Sorry to hear that you hit the deck though! Hope you and the ebike get built up again harder, better, stronger, faster 8)

 

[adrian_sm]

Yep got everything from John. He is getting a shipment of parts in the next few weeks, so will be out of action for a bit.

On a side note, I ripped the remaining electronics off the bike and rode in to work today old-school style.
Survived the ride in. Just got to get used to going slowly again.

I tracked my progress with a GPS, and have just finished massaging it so I could compare my speed between electric and non-electric for an almost identical path. Speeds might be a bit over estimated, I haven't done a lot of averaging so gps location error will inflate speeds.

Still interesting...

 

[ElectricEd]

Hi Adrian,
I bought a spare cover from Crytalyte Europe, http://shop.crystalyte-europe.com/product.php?productid=16203&cat=263&page=1
It arrived fairly quickly and had a steel reinforced threaded boss. This means it will be unlikely to have the same problem again.





So if John at TheBike can't get one, you now have a backup supplier.

BTW, where in Melbourne can you ride 150 metres below sea level?

 

[Reid Welch]

Some things never change,
especially in learn-from-scratching-head, CHINA.

IN NINETEEN HUNDRED
AND A TEN

THE AU-TO-MO-BILE'S FI-NEST MEN

WARNED: AL-U-MIN-I-UM IS Grand!
UNTIl IT CRUMBLES NEAR YOUR HAND.

A-LU-MIN-UM (USA name)
AL-U-MIN-I-UM (UK name)

"THE TROUBLE METAL"
they called it then.

I know so
'cause I read so
in prime-era publications.

I know so
be-cause I con-versed,
as a child with men
who re-paired autos

long before the year or state
of nineteen hundred
one plus eight.

__________________________
__________________________________________

 

[adrian_sm]

Hi Adrian,
I bought a spare cover from Crytalyte Europe, http://shop.crystalyte-europe.com/product.php?productid=16203&cat=263&page=1
It arrived fairly quickly and had a steel reinforced threaded boss. This means it will be unlikely to have the same problem again.

So if John at TheBike can't get one, you now have a backup supplier.

Thanks for the backup plan.

Is that a bearing on the outside, or a rubber seal? Would be nice if it was a bearing, as this would mean the threaded boss is not so canitlevered?
It also looks like they have been a bit more generous with the fillets this time around which is nice.

BTW, where in Melbourne can you ride 150 metres below sea level?

:lol: Just setting up the graphs axes to seperate the curves, and just incase I want to do the "Reid amphibious evehicle mod."

 

[Reid Welch]

:lol: Just setting up the graphs axes to seperate the curves, and just incase I want to do the "Reid amphibious evehicle mod."

Laugh along. I sure do!
That bike's not been touched upon since June.
I got that LIME and now I'm focused on getting it up to its "hocus pocus".
It was working great!
Until it ate...the pavement last week.
---

The submarine bike just stares at me.
I need to paint and re-wire
torn
hub-wire-exit-try.

Have been not so well,
and have a date
to go to court and fight a fate
more important than a bike.

But RIDE I WILL, that yellow bike!
across or in the ocean.

OR strap lead belts on my waist
and drive it from an open dock,
throttle full, and fast, wide open.

:|

 

[voicecoils]

So if John at TheBike can't get one, you now have a backup supplier.
BTW, where in Melbourne can you ride 150 metres below sea level?

Adrian got his ebike parts from John at EMTB not John at The bike. Both are in Melbourne though!

I want to know how Adrian kicks it up to 65km on a gentle downslope! (faster pedal powered too!) And how does he manage not to stop for any lights!

My ride to work is frusteratingly stop-and-go.
1 massive set of stairs off the harbour bridge
2 roundabouts
7 intersections
58 freakin' traffic lights
and all in less then 15km each way

 

[HighTekBikes]

Damn, I've never seen one sheared off like that. Yes, I thought he meant he stripped the threads which I have seen. I guess the motor torque did most of the damage causing a stress fracture, then you finished it off when you stood on the pedal? What was the max power you were running? How many months or years? I wonder if that was a manufacturers defect or design error. It would probably be a good idea to check those motors for cracks on high powered/loaded setups.

 

[adrian_sm]

I want to know how Adrian kicks it up to 65km on a gentle downslope! (faster pedal powered too!)

The motor is a liability above ~ 54km/hr, acting like a brake. So my pedal power not only has to get over the wind, but also charge the bloody batteries.
That was the thing I noticed the most riding today without the motor, how easy it was to pedal going down hill. Even below the back EMF limit, the efficiency is rolling off meaning you are still fighting the motor.

Of course going back up that hill, I was screaming for a motor, as my face started looking like this .

And how does he manage not to stop for any lights!

Ah the magic of dodgy GPS tracking, smoothing out details like that. It had the minimum 100m distant filter on, so doesn't really show stops properly.

My ride to work is frusteratingly stop-and-go.
1 massive set of stairs off the harbour bridge
2 roundabouts
7 intersections
58 freakin' traffic lights
and all in less then 15km each way

Damn. 58 lights is insane. I luckily have some pretty sweet back roads. So I am only mixing with the cars for about a third of the ride, and that is all on nice dual lane ways.
As for lights, I have a route that gets it down to 6 sets, and two of those help me turn right across decent traffic. But three right turns have me sitting in traffic. Not so cool.

 

[adrian_sm]

How many months or years?

Only had it for 3-4 months. Done about 1700 kms, on roads commuting to and from work. No jumping or anything fun like that.

What was the max power you were running?

48V, 35 Amp controller. But never see over 20 Amps unless I go full throttle from a standstill.
So nominally 500-700 Watts.
But this shouldn't put any real stress through that part of the side cover. As the torque is transmitted from the wheel, via the magnets to the windings, down through the axle to the dropouts, to push me forward.
It is the vertical loads of the bike weight, and hitting bumps, or the load from the chain on the freewheel that would try are rip the bearing or screw boss out of the side cover.

I guess the motor torque did most of the damage causing a stress fracture, then you finished it off when you stood on the pedal?

Nah. The daily stresses of concern would be impacts, and pedal power. Plus any misalignment in the parts causing cyclic stresses.

I wonder if that was a manufacturers defect or design error. It would probably be a good idea to check those motors for cracks on high powered/loaded setups.

Definitely a combination of both.
- The design has sharper corners in all the wrong places, which doesn't allow the forces to even out smoothly and reduce the stress on the casting.
- The freewheel bose is not supported internally at the outer edge. So pedal loads result in a unwanted moment trying to bend the free wheel out of the side cover.
- Thin walls on the side cover don't help.
- Plus cheap casting that have internal oclusions, to further raise the stressed.

Add that to my style being slack and not changing down gears when I get to lights, resulting in nice high torque on the freewheel as I stand on the pedals and wait for the motor to get the speed up to where I can contribute properly, adds up to a dead 408, and me sitting in the middle of the road worried about cars running me over.

From the pictures I have seen of the new side covers, it looks like they have address some of the issues, some hopefully it won't happen again.

John from e-mtb has been jumping these things, and putting them through a torture test and hasn't had any break on him. So hopefully that means I just had a dodgy casting, and a new one will be sweet.

Heres hoping.

 

[SniperGaulois]

Thanks for the heads up! nightmare! wouldnt want that to happen on a pothole speeding down a hill at 50kph! death prone!

yes i dont like how the crystalyte hub wobbles relative to the axle, really bad news now i have read what happens as a result.

cant wait to get a nine continents motor, much better uniformity according to the ebike ca place.

 

[ElectricEd]

Adrian wrote:
Is that a bearing on the outside, or a rubber seal? Would be nice if it was a bearing, as this would mean the threaded boss is not so canitlevered?
It also looks like they have been a bit more generous with the fillets this time around which is nice.

It's a seal, the bearing is inserted from the inner side, you can see the bearing recess in the second photo of my previous post. With the new steel threaded boss the cantilevering of the cluster is not a problem as it is now supported over a larger area of the side cover because of the size of the steel insert.

 

[adrian_sm]

Well I am back on the road. Woo hoo. Only taken it for a quick test ride around the block, but will be riding it in to work again tomorrow.

It couldn't have come soon enough. My drive to work today took nearly 40 minutes. I could have ridden to work, and had a shower quicker than that on my ebike.

John @ e-mtb got a new side cover flown in, and swapped it over for me. He was great about the whole thing. But was surprised at the failure since he has been treating the pretty hard on his dirt-bikes and never had one fail on him. Gues it is just luck of the draw with the chinese "Quality Control" on these hubs.

The side cover was one of the newer style with a steel insert, and more generous radii, like Electric_Ed posted. I hope it lasts. It is not fun hitting asphalt and having to get rescued. I would much prefer spending extra cash for something I can rely on. Time will tell.

On a side note, while I was waited for the motor to be fixed I was commuting the old fashion way. And although I had to get used to travelling a bit slower, I wasn't huffing and puffing too much on the hills. So regularly travelling via ebike for me has definitely improved my fitness, over my previous once or twice a week riding in without electric assist.