Opening a hub motor - FAQ

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Opening a hub motor - FAQ

Post by auraslip » Jul 26 2011 1:13pm

This is easy cheasy once you learn how, but it can be a major PITA if you don't know the tricks.

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Here are the tools - you don't need all of them, but it helps.

A automotive 3 jaw pulley helps immensely, but is not required.

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Remove disc and freewheel and cut off connectors. I'm lucky to have a desk that makes this easier, but you can use blocks of wood or even two chairs.

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The first step is to use either/or the box knife and sharpie to mark the motor so that the cover can be put back on the same way. This is because the motor covers aren't machined precisely, and if you don't put it on the same way you may get some scary rubbing sounds for the first hundred miles.

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Ok. You CAN use a power drill to undo the bolts. My drill bit set didn't come with the appropriate allen key, but a square bit works. HOWEVER, the screws are made of VERY soft metal and WILL strip VERY EASILY and then you'd be VERY (un)screwed! Loosen first and tighten last manually with an allen key. You're supposed to do this in a star pattern to tension properly, but that's more important when tightening.

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This makes life easier.

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Now use the smallest flat head you have. Eyeglass kits are available at the dollar store and on ebay. Insert it in a screw hole so you may see how far it is going in. It is VERY important that it doesn't go in too far!!!!

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If it does, it could break a motor winding and then the motor may be done for (unless you feel like rewinding the damn thing)
EDIT: it's been pointed it out that the screw holes are the weakest point on the cover and you should pry up on them. It's probably fine to tap the screwdriver in there, but don't pry up there. Another option is to mark the maximum depth on the screwdrivers themselves.

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Work your way up in sizes going around the motor in a star pattern - careful to not hit the windings. This is hard the first time you open it as the motor is sealed with some water proof glue.

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Once it's open big enough to fit the box wrenches in, you should be able to easily pry it off.

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Once the cover is lose, it may not come all the way off. Flip the motor over, put your arms through the spokes, and press like hell on the back side of the cover. It may be a PITA but it WILL pop off eventually. Just be careful not to impale yourself on the axle when it finally gives.

If someone has an easier way to do this step, I'd love to hear it.

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That's it! Now you can replace burnt out hall sensors, ventilate the covers, upgrade the phase wires, and install a temp sensor. All of which I'll be covering soon.

I don't think many will be interested in removing the stator as almost all the mods and repairs don't require it. If you'd like to though, here is a useful video.
Last edited by auraslip on Jul 27 2011 12:13pm, edited 1 time in total.
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Re: Opening a hub motor - FAQ

Post by auraslip » Jul 26 2011 1:15pm

Oops, meant to put this in ebike technical.


(mod edit: fixed that for ya. :))
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Re: Opening a hub motor - FAQ

Post by Pure » Jul 26 2011 4:58pm

Great thread, very informative!
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Re: Opening a hub motor - FAQ

Post by dogman dan » Jul 26 2011 6:07pm

I like to use an old steak knife to get that first crack to open up.


If you have a puller, you can use it as a pusher, and simply push the whole thing out the other side, windings and all. Then you don't have pry anything. But this method works fine, and I still use it at times even though I have a puller. Sometimes I just want the cover off, and need to get it started to use the puller.

If you don't have a puller, then you can just keep prying up, but using wider and wider tools. After fat screwdrivers, move to prybars or claw hammers, then small blocks of wood can be put under the prybar. Just keep making the crack small with something so you can keep prying.

Lastly, there is the wood block trick. you loosen the cover, then rap down the opposite side axle on the wood block, till the whole stator pops out.

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Re: Opening a hub motor - FAQ

Post by John in CR » Jul 26 2011 6:19pm

The only thing I'd add is to stay away from the bolt holes when popping it open. That is the weakest part of the flange on the cover and where you definitely don't want to mess it up.

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Re: Opening a hub motor - FAQ

Post by auraslip » Jul 26 2011 7:37pm

Good stuff guys. I'm in the process of upgrading the phase wires and documenting it.

It is very, very hard. I'm thinking you pretty much need high thread count wire, teflon heat shrink, 30 gauge teflon hall cables, and a titanium drill bit to bore out the axle.

I have none of those and even just 12 gauge radio shack wire is a god damn chore, let alone the temp sensor and hall wires. And I'm using copious amounts of hand soap :x
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Re: Opening a hub motor - FAQ

Post by Philistine » Jul 26 2011 7:47pm

It is very, very hard. I'm thinking you pretty much need high thread count wire, teflon heat shrink, 30 gauge teflon hall cables, and a titanium drill bit to bore out the axle.

I have none of those and even just 12 gauge radio shack wire is a god damn chore, let alone the temp sensor and hall wires. And I'm using copious amounts of hand soap
Hey Auraslip, did you try LFPs method of removing the silicone from the wire, and replacing it with heatshrink? When I did my 9C, I stripped off the coating of some 12 Guage wire, and replaced it with heatshrink, and that went in a breeze, wasn't hard at all. 10 guage was a major pain and I gave up with the cursing and the swearing (I don't know how LFP did it with 10 guage), but 12 guage went in easy as.

Good work doing a thread on removing the cover for those without the puller, but in my opinion if you can spring the $30-50 for a puller, why take the stairs when you can take the elevator?

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Re: Opening a hub motor - FAQ

Post by liveforphysics » Jul 26 2011 8:51pm

Philistine wrote:10 guage was a major pain and I gave up with the cursing and the swearing (I don't know how LFP did it with 10 guage), but 12 guage went in easy as.

Because I am a Jeti-Ninja who M.C. Hammer's all things I view to be worth doing. :P :mrgreen:

But seriously, I took me like 3-hours of cursing and thinking of going to 12awg myself before finally getting 10awg. Then the second time I did 10awg (and is also has pics in a thread here), I didn't struggle quite as much because I drilled it a little bigger to make life easy on myself.


Nice guide on opening a hub Aura! I would also mirror John's sentiment about not prying at the screw hole, but rather draw a little depth line on the screwdriver so you know your safe insertion depth limit. I've opened a number of hubs, some of which were well glued/painted tightly shut on the side covers, so I found starting off by inserting the blade from an old razor knife into the gap and tapping it it can help to get a stubborn one open enough to tap in a small screwdriver.


For getting the stator out of a motor laced into a wheel, I like to just set the wheel on the floor with the axle side down and the removed cover side up, then carefully step onto one side of the wheel, balance, and start stepping down on the other side, and the stator just jumps up so you can grab it and lift it out. Requires only a floor and about 10second of work.
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Re: Opening a hub motor - FAQ

Post by grindz145 » Jul 26 2011 9:49pm

Nice man! Replacing broken halls will be a fantastic resource to have. I bet there is a solid majority of people joining this site because they've burned up a hall.

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Re: Opening a hub motor - FAQ

Post by auraslip » Jul 27 2011 12:11pm

For getting the stator out of a motor laced into a wheel, I like to just set the wheel on the floor with the axle side down and the removed cover side up, then carefully step onto one side of the wheel, balance, and start stepping down on the other side, and the stator just jumps up so you can grab it and lift it out. Requires only a floor and about 10second of work.
Pro-tip there.
But seriously, I took me like 3-hours of cursing and thinking of going to 12awg myself before finally getting 10awg. Then the second time I did 10awg (and is also has pics in a thread here), I didn't struggle quite as much because I drilled it a little bigger to make life easy on myself.
Really, I know it shouldn't be hard. You just need a precise method and it needs to be followed. I think just about everyone is going to struggle with it until they figure out what works for them.
Hey Auraslip, did you try LFPs method of removing the silicone from the wire, and replacing it with heatshrink?
Yes, I removed the original insulation and replaced it was some cheap ebay heat shrink that shreds too easily. That and the fact that I'm using stiff, thick, radioshack wiring is probably the issue. If I'm gonna take the time to wait for the proper teflon insulation, 30awg teflon hall wiring, high thread count (right term?) wire, and drill the axle out I might as well try for 10awg.
Nice man! Replacing broken halls will be a fantastic resource to have. I bet there is a solid majority of people joining this site because they've burned up a hall.
One of the older guys posted a really good guide to replacing hall sensors, but it's buried in a thread and the photos may or may not have been snarked.
I would also mirror John's sentiment about not prying at the screw hole, but rather draw a little depth line on the screwdriver so you know your safe insertion depth limit.
Brilliant.
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Re: Opening a hub motor - FAQ

Post by nicobie » Jul 27 2011 12:42pm

If using the "place on floor and stomp on rim" method, be sure to follow LFP's advice and keep the wheel level to the ground when stomping or you will bend some of the stator laminations. It's alot easier with 2 people.
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Re: Opening a hub motor - FAQ

Post by John in CR » Jul 28 2011 12:55pm

My favorite tool for popping the covers is a nice sharp 1" wood chisel. I bought a cheap one just for that purpose. It gets the gap started and a couple of wide tip flathead screwdrivers finishes the job without messing up the nice edge on the chisel.

Regarding replacement wires, the one I did with magnet wire was a dream, because it was so easy. The only issue was getting the varnish off the ends easily and cleanly for electrically joining all strands. I feel comfortable with the 3 layers of insulation that take up very little cross sectional area. The high temp varnish on the magnet wire insulates the 3 phases from each other, and is the innermost layer of protection. Then I did a single wrap of electrical tape to easily create a nice neat round bundle including the hall wires, and because I don't fully trust shrink wrap as the only protection against chaffing of a hub motor wiring harness. The outer cover of the harness is shrink wrap. This permits low strand count for better copper fill, but since it's not twisted the cable remains quite flexible.

If someone knows a reliable way to get that varnish off the ends, please share it. That's the only issue keeping me from enthusiastic recommendation.

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Re: Opening a hub motor - FAQ

Post by John in CR » Jul 28 2011 1:00pm

nicobie wrote:If using the "place on floor and stomp on rim" method, be sure to follow LFP's advice and keep the wheel level to the ground when stomping or you will bend some of the stator laminations. It's alot easier with 2 people.
The newer motors I've opened all have had some sealant around the flange of the covers, so no way I'd think of using that method. Popping it with a sharp but strong blade like a chisel is just too easy anyway.

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Re: Opening a hub motor - FAQ

Post by John in CR » Jul 28 2011 1:07pm

One other thing I've started doing right when I get a motor in is to use a center punch to mark each cover and rotor ring. I put one alignment dimple on each on one side and 2 on each on the other side. That way even if the motor gets repainted somewhere down the line or gets a new owner, the covers can always be easily matched up to the proper side and position. I used to do scratches, but I find the dimples to be quicker, easier, and more effective.

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Re: Opening a hub motor - FAQ

Post by Beavinator » Jul 28 2011 1:16pm

Im with Philistine on this one. My 3 jaw puller just makes this job so easy! Everyone should own one that works on e-bikes.

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Re: Opening a hub motor - FAQ

Post by John in CR » Jul 28 2011 1:46pm

Using a pulley puller is usually just a waste of time, because you have to pop the covers loose to get the jaws on in the first place, and for most motors the cover comes right off after they are popped loose. They can't be used to get the wire side cover off of a wire through axle motor anyway. Where the wheel puller comes in handy is pulling the rotor ring off at no risk of getting pinched, especially the big scooter motors where just manhandling it isn't so easy. You can pull the stator ring and one cover off in one shot with a puller, but once you start to apply pressure, it's really best to go around the joint and start the gap, because those cast AL covers aren't very strong to side forces, which can be substantial with a bit of sealant around the flange acting like glue.

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Re: Opening a hub motor - FAQ

Post by itselectric » Jul 28 2011 3:05pm

auraslip wrote:This is easy cheasy once you learn how, but it can be a major PITA if you don't know the tricks.

Image
Now use the smallest flat head you have. Eyeglass kits are available at the dollar store and on ebay. Insert it in a screw hole so you may see how far it is going in. It is VERY important that it doesn't go in too far!!!!

Image
Work your way up in sizes going around the motor in a star pattern - careful to not hit the windings. This is hard the first time you open it as the motor is sealed with some water proof glue.

I don't think many will be interested in removing the stator as almost all the mods and repairs don't require it. If you'd like to though, here is a useful video.
auraslip:

I personally had a open alot of hub motors in my life time. The video link is our video. And I just like to point out a good tip, it is not advise to place the screw driver under the screw hole and pile and lift it open. This the weakest point of the cover plate, and it's easy to break away if you can't get far enough in. It is advise to pile and lift the cover between the screw hole.

Ken

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Re: Opening a hub motor - FAQ

Post by auraslip » Jul 29 2011 4:17pm

Thanks ken. I've already edited the original faq.

John - I like your idea for magnet wire. Where did you get yours? Is there a more in depth discussion of it?

edit: I've read through all your posts on it, I'm just gonna start a new thread because it's worthy of more discussion.
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Re: Opening a hub motor - FAQ

Post by ryan » Aug 12 2011 11:58am

Can someone point out how to do this on a Crystalyte x5? This method won't work because you have to go through the side. Thanks.
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Re: Opening a hub motor - FAQ

Post by itselectric » Aug 12 2011 3:45pm

ryan wrote:Can someone point out how to do this on a Crystalyte x5? This method won't work because you have to go through the side. Thanks.
Perhaps, you missed the video link?

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Re: Opening a hub motor - FAQ

Post by Bonvin » Feb 12 2012 12:51pm

Hi

I have read with great interest your "Opening a hub motor - FAQ"

I have a 9C rear hub but on a 20" wheel. I have 4009 Km on this hub and love it :)

In your FAQ you have remove the wire side cover

I will like to know if it's possible to do the same thing, for the other cover, on my rear hub.

I will like to open one side without removing the connectors.

Thanks in advance.

Bonvin[/size]

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Re: Opening a hub motor - FAQ

Post by ian.mich » Jul 18 2012 4:46pm

gear pullers the only way to do it right

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Re: Opening a hub motor - FAQ

Post by Looncan » Nov 15 2015 8:00am

i love how nobody ever mentions freewheel removal, it just magically disapears on every single tutorial on the web

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Re: Opening a hub motor - FAQ

Post by Voltron » Nov 15 2015 9:55am

Several of the motors I've had to open had screw on sideplates, that is, the whole sideplate is threaded around the perimeter, with no little screws... so check that before you go hammering things into the seam because it wont get you far.
On a separate note, had another guy help me slide a stator back in to one,,,he's a low key, not impressed by much kinda guy,,, the shock on his face as the magnets grabbed was priceless even though I warned him how much it was going to jump in there. :wink:

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Re: Opening a hub motor - FAQ

Post by amberwolf » Nov 15 2015 4:45pm

Looncan wrote:i love how nobody ever mentions freewheel removal, it just magically disapears on every single tutorial on the web
My guess is because freewheel removal is "standard", in that there are existing tools for that sort of thing that are easy to find, along with instructions on how to use them. ;)

But it would be nice if that was mentioned in teh tutorials.

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