It’s all about the tolatances! If I hear something about retaining fluid, I know that somebody missed the tolataneces and fucked up. 0.4 gap for a bearing? That’s a joke! No wonder that the bearing seats don’t last. If you are working with bearings and bearings seats you have to talk about hundreds. The size of the shaft is scondary if everything else is great and there is no room to wiggle. I had some lessons in mechanical engineering and know what I say. Marketing BS…
Of course based on your hubs…the size of your hubs caused the axel failure…you just gave it more leverage by extending it. Basically, running over a rock near the center puts less force than a rock ran over by the end of your wheel…
The hubs out now are close to spec…at least enough as not to need a 12mm axel. In the case of your hubs, who’s to say 12mm is enough? When does it become a ridiculous size? Most of the hubs out are trying to look like regular wheels as opposed to yours.
So, to defeat the strain we need to put the esk8 stuff on steroids? Bigger wheel, axle, bearings etc…it’s not looking like a longboard wheel to me
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I’m saying the airgap on a motor is maybe .4mm if it’s trying. The bearing fit is much more detailed
If it was impossible to hold a bearing in place, planes would to fall, cara would drive on each other and so on
The truth is, pure interference fit is not always enough. Is it enough for a hub motor? I don’t know, it requires a complex analysis of the problem and measurement and determination of all loading scenarios and lots of data capture
What’s is done on most machines and equipments is even with interference fit you have a secondary locking method, a lid, a cir clip, counter nut and so on
In my machine element class if you submit one of the projects and it has a bearing being fixed only by interference consider yourself reproved, but this is kind of extreme case, but good practice, hub motors don’t have lots of free space, is all about compromises
The best way for us to determine that is to watch what’s is happening with everyone’s hub’s and take action from there
General design rule with bearing in a hub motor are to be press fitted.
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wow, I never knew you could have one mottor hooked up to two wheels! Doh! - how did you do it
Just for the sake of expanding the field.
We Don’t want a satellite system or want an alternative to a satellite system. So why revolve the conversation around hub motors ?
When all we want is an alternative to satellite systems and the whole shit to be attach on the same axel as the motors. For this we can be discussing straight up direct drives, direct drives with planetary gearing and so much more but instead we are having a conversation among peacocks.
Nice !
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Trillium hubs… soon. Been saying this forever, sorry. Best balance of form and function (and <800 grams). Requires special tooling and has taken a long time to develop. 95% US made (bearings are chinese sorry). ridetrillium.com
There is absolutely no information on that website without signing up/giving your email address.
There is no information regardless at least right now… Site has been up for a long time… 
and no emails have been sent but many received 
regardless if you want to call it machine engineering or physics, your picture with the different fits…are you anywhere on it other than in the “loose” area? it seems that’s all anyone does and in which case things don’t have to be very precise. Wondering if you think it would be possible to do interference fittings anywhere on that motor or if you had plans to. Maybe it’s not possible. How about looking into the thermal expansion, and deformation values, and surface area, of the aluminum housings and figure out if it’s possible. some machine engineering. interference fitting heavily loaded aluminum housings…maybe it would work. Then you’d at least have half interference fittings on the softer metal side
@Trillium do you have anything made yet? can you elaborating on what you’re talking about. Are you doing intereference fittings on aluminum? That seems more complicated but maybe it could be done and last http://www.nskamericas.com/cps/rde/dtr/na_en/na_literature_bearing/07_TechTalk__Getting_a_good_fit.pdf @Kaly don’t know why peacocks but those other drive methods…as long as they aren’t heavily loaded, like a hub motor is, then they shouldn’t need the interference fitting. Probably better to have the slightest interference fit anyway @Michaelinvegas U ask a lot of questions that I forget but The 12mm axle is for the greater leverage and torque. All motors are putting double if not triple the leverage in the axle. Axles need steroids yes. The bearing interfaces being interference fits is so the shafts and housings the bearings are on don’t get deformed by shock loads that the motors experience.
Working with hummie, I have been testing his small motors for about a year now. I have put somewhere in the ball park of 1500 miles on them in that time. Over time, I have noticed that the bearings start to wobble a bit (not enough to make them unusable, but enough that I can notice it). When you look at where the bearing sits, you’ll see some very slight wearing away of metal. I experience this same thing on my regular skateboard after some time. At some point, with the tight airgap of these motors, the stator will start rubbing on the magnets. Then the motor will short, and it will be dead.
Unless the raptor 2 is doing a pressed fit bearing, than you can expect to see the same deterioration. The rate will depend on the materials used and the loads on the bearings. It’s possible they could last long enough to at least get out of the warranty phase, but unless you press fit them, you’ll see wear over time.
300 miles is nothing in hindsight. This is why you can’t rush the release of a product @onloop. You love to talk shit about how long we are taking to build a complete. But do we just overlook the minor details and assume that the problems of others can’t also be our problem, or do we test long enough to find those problems? 3 months for a new motor, new board, ect. is not enough time to test. Look at Mellow. They could have been one of the first hubs on the market, but they didn’t want a crappy product. They wanted a flawless product. They cost a fortune, but I bet they won’t fall apart on anyone. What do you think makes you so different that you can skip the long term testing phase? Short term tests showed me some of the flaws of these motors as they are now, but it didn’t show me the biggest flaw of them. This is why we’re sitting and not just releasing a product.
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@Hummie and @evoheyax reasonable observations indeed.
Maybe we should just make call this thread, Why all bearings will fail. Lol
It’s interesting to hear abt the failures and how they are over come. As @Mikenopolis mentioned it would be interesting to see mellow pipe in on this from their experience. Myknowledge is limited to carvons at the most basic level.
But it all makes sense, what everyone says. But there can’t be only one way to resolve the issue…is there? There can’t be one issue with hubs that kills them? Are all hub motor designs the same? Will making stronger parts make it last longer? Will making it bigger make it last longer?
Hubs are new territory for esk8 … I guess will shall all see
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Steel,… aluminum maybe in the future… requires a lot of care to do aluminum… would need thick cross section at least 5mm so takes a lot of space
I have had 3 prototypes spinning. All 28 pole in 75mm wheel. It’s sort of silly how I did it but I wanted to push the limits of smaller diameter motors because that’s the only way to get the weight and form factor down to a normal place.
Interesting. Hope u don’t mind the detailed questions, it’s an info forum and I’d like to think we can all share our info. So ur using steel shafts and housings. What type? I’m doing 1144 for the shafts and 1020 for the rotor. And how much interference did u put and is it on both sides of both bearings? Getting parts cut to such a detail was hard to find. I’m doing just .005mm on all surfaces. Not much but recommended. With the shrink fit it holds better than a press fitting and will see
U have any pics or 3D drawings of the design @onloop nothing redicilous about it. I’m not saying my design sucks…I’m saying anything with slide fittings does. What’s your tolerances and what material they sitting on. The fact that you say u tried lots of stuff and they’re all mechanically fine makes me think you’re in the dark @Michaelinvegas the bearings might be fine with use as they’re the hardest material and it’s the shafts and housings that rattle their way down
You sound envious and it seems like you’re trying to pick a fight with Onloop arround every corner. It looks kinda silly.
Ontopic: How many miles should a hub motor last? If the hub motors break down after 3000 miles because of mentioned problems, for how much people would that be a problem? And 5000/10000/etc?
Heavy usage scenario: Work - home commute (10 km + 10 km) when the following criteria are met:
- above 10 degrees
- not raining
That might be 200 days per year in some scenerio’s. So thats 200 traveldays x 20 km per year. = 4000 km On top of that the board is used for fun an extra 40 km per week. 40 x 52 = 2080 km
So 6080 km per year sounds reasonable for a heavy user. So thats 12160 km for two years.
Could Raptor 2/Enertion/Mellow hub motors avarage 12160 km’s before breaking? What do you guys think? I don’t think a high % of people would come close to that many km’s per year though.
If 10% of users make enough km’s per year to wear the motors out in two years. The company providing warrenty should’t have a hard time keeping everyone happy.
Is a much higher percentage breaks down the situation could get ugly I assume.
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I am sure @Mellow will do that without problems, they beat the shit out of their products in testing and i am sure they have some prototypes that already have done more and they have done over 2 years of R&D in Hub motors so i am sure they have come across these difficulties as well.
If the Raptor 2 will do it? (Based on my experience with them:) Maybe. I doubt that the first 200 will hold up based on previous experiences with enertion, even if it is just “the Manufacturers fault”. In the past, their ideas, their innovation and their marketing always were miles ahead of the Processes and the Products. Until i get some unbiased review, i dont believe that the Raptor 2 will be as good or as long lasting as onloop tells. Which does not mean it is a bad product.