Stromer motor water ingress then freezing problem

[bluecat]

Very unfortunate but it’s part of the design flaws of hub motors in general. Hubs are more exposed to the elements especially being in the rear wheel with all the snow flying around the rim and saturating the motor. Mid-drives are insulated from this and aren’t affected. One of the many pros of mid-drives over hub motors.

I can't follow this statement. I'm looking intensive on the pictures of a Stromer after a heavy snow, salt and sludge ride published above. The motor is the sole parte with almost no snow....

Furthermore, I can't solve the equation:

How many milliliters of water might be needed to get the motor blocked by freezing - if you consider the size of the wheel which is the size of the lever? And now: Why did this amount of probably salty water not lead to a short circuit during the ride?

 

[Johnny]

Yeah that lockring is fully secure with it holding the cassette to the freehub body.

Usually it is good to check, It may feel secure to touch even when it is a bit loose.

Yes I saw that they did design it differently thanks to your video and have no locknuts. But It looks like if the axle is torqued right it should be fine (I thought the hub was not secure at all). Since you have greased it very well I don't see how in a short amount of time it can ingress that much water again.

Anyways the shop got back to me saying Stromer diagnosed the old motor state the seal failed. The shop will diagnose the electrical this time around and possibly put another new motor on. Hopefully this will fix the problem.

I'd say it's probably a design flaw with this Cyro drive.

It is good that they diagnosed your problem and identified the seal that failed. When they replace the motor again I would ask them to see why it failed.

It is an older gen motor, I don't know if there is a design flaw or not. Hopefully it is preventable and you don't have to deal with it again.

Let us know what they say.

 

[Johnny]

I can't follow this statement. I'm looking intensive on the pictures of a Stromer after a heavy snow, salt and sludge ride published above. The motor is the sole parte with almost no snow....

Furthermore, I can't solve the equation:

How many milliliters of water might be needed to get the motor blocked by freezing - if you consider the size of the wheel which is the size of the lever? And now: Why did this amount of probably salty water not lead to a short circuit during the ride?

If anything, mid drives would be a bit more susceptible to salt/snow since they are located where the bottom bracket is and closer to the ground. They are constantly sprayed with salt/slush, especially from the front wheel. Moreover for every mid drive in the market there are examples of water ingress as we have pointed out earlier, so this is not a mid or hub specific problem. Don't bother with the irrational claims of individuals who have no experience with these bikes and/or live in mild climates where it rarely snows and the temperature almost always stays above 5C even at its coldest.

Returning to OP's problem, maybe you can comment on that since you seem to have experience with all of the Stromer's offerings and have ridden them in harsh climates.

His claim is that, since the freehub is not fixed to the motor plate with a nut,(instead a portion of the axle housing is attached to it, then the tip of this tube is forced towards the motor plate when the axle is tightened) the salty water is finding its way into the motor by passing behind the cassette in between freehub and the motor plate. This is a reasonable claim yet it seems a bit surprising given that he put a substantial amount of marine grease right behind the freehub.

 

[bluecat]

His claim is that, since the freehub is not fixed to the motor plate with a nut,(instead a portion of the axle housing is attached to it, then the tip of this tube is forced towards the motor plate when the axle is tightened) the salty water is finding its way into the motor by passing behind the cassette in between freehub and the motor plate. This is a reasonable claim yet it seems a bit surprising given that he put a substantial amount of marine grease right behind the freehub.

Imagine this was the case - how much water would it take? It's a rotating part, why should water flow into the motor? When you use a high pressure cleaner, you will damage a lot at the Stromer, but still with a powerful Kärcher, I don't see a way to press water into the motor. But these are only my thoughts around the equation mentioned above.

On the other hand, we have a lot of postings in the stromerforum.ch None of them describes a similar issue. All together brings me to the conclusion, that the cause of the damage of its motor is not water inside. The reason must be something different.

 

[PedalUma]

When the temperatures are very low, I wouldn't leave the bike outside, can you bring it inside where you work?
Also dunking hot water over the bike may not be the best practice. I rinse the bike by a light spray of warm water(again garden sprayers are perfect for that) and wipe afterwards.

Was there water inside the motor ? Pictures would be great.

I use a garden sprayer daily to clean bikes. It is low pressure, controlled. It is dedicated for this purpose. Water only. But if left in Kmosdell's garage, it too would freeze. Bike grease is good. Silicone plumbing grease on seals keeps out water and is compatible with rubber seals and O-rings.

 

[PedalUma]

All motors breathe, even sealed ones. They are not diver's watches. I am writing this after reading the entire thread. Swings in temperature change air pressure inside motor housings. When the motor heats some air is expelled. As a motor cools it brings some ambient air into the motor. Then any ambient humidity brought in with that air will condense inside the cold motor. I take apart and reseal the front and underside of most new mid-drive motors that I install using automotive gasket maker. But I always leave a little breathing hole at a high spot toward the back to let humidity out. I also store bikes at human habitat temperatures. An internally geared Alfine or Nexus hub is nice on ebikes. And there are belt drive systems that do not require a break in the seat stay.

 

[kmosdell]

I also store bikes at human habitat temperatures.

a lot of postings in the stromerforum.ch None of them describes a similar issue.

Leads me to think, am I the only one who store their $4.5k ebike in the cold?

 

[PedalUma]

I treat eBikes like they are musical instruments. Pianos and violins don't like dramatic swings in humidity and temperature either.
Here is an electric bike I made today! The gears are not exposed to the elements because they are in a sealed Nexus hub. The motor has also be opened and resealed with automotive gasket sealant. Sealed gears weigh more but the trade off is usually worth it for reliability for commuters with lower maintenance. Cyclists who bikepack across continents also prefer sealed gears. The shifting is smooth and can be done while stopped at an intersection. The battery fits in a standard water bottle cage and can be removed in seconds. This town bike comes in at 19.25Kg. Total under $2000. Last week I made a 35 pounder. The weight distribution on this bike is 56% to the rear for traction and 44% to the front for handling. It goes up and down curbs easily. Note the absence of messy wires.

 

[bluecat]

All motors breathe, even sealed ones. They are not diver's watches. I am writing this after reading the entire thread. Swings in temperature change air pressure inside motor housings. When the motor heats some air is expelled. As a motor cools it brings some ambient air into the motor. Then any ambient humidity brought in with that air will condense inside the cold motor.

You've read the entire thread? So, how many water would it take to freeze down a Stromer motor?

I don't live in the US, having only experience with the Swiss winters. I've never taking a ride below -15ºC because it was never colder than this in my area. The temperature in my bike shelter box will be the similar as in his garage.I place the Stromer with the hot motor in the box and take the battery out (to warm up first, then recharging). as you mentioned, the motor will cool down and breathe (= air from outside goes into the motor) If you're familiar with Gay-Lussac's law, you can calculate how much. But it's winter - so the air contains almost no humidity!

 

[kmosdell]

so the air contains almost no humidity!

I think it's sucking in all wet and snow that's stuck to the motor.