48V 1000W rear hubmotor project (now with pictures)

Little-Acorn

100 W
Joined
Oct 15, 2009
Messages
130
This may turn into a long, serial thread. I ordered and paid for a 48V, 1000W rear hubmotor from daoji888 of YXM Corp. in China, on Oct. 29. They shipped it on Nov. 5 (700c rims were out of stock, hence the delay), and today (Sat. Nov. 14) I got a call from the post office saying a big box had come in by EMS after the daily carrier had left, and should they send it out next Monday or would I like to pick it up?

I managed to not break too many speed limits on the way to the post office (if you never fall below the speed limit during the entire trip, that counts as only one violation, right?), and was shortly unpacking the big box in my garage. It appeared to have gotten a medium amount of pounding from China to here, but was serviceable, and after unpacking I didn't see anything that appeared to be broken or missing. I'd say it was well enough packed. I could see ways to do it better, but OTOH the proof is in the pudding: It got here apparently intact.

The tire on the 700c wheel is a Cheng Shin 700Cx40, looks pretty rugged. Normal street tread, not a knobby or a slick. Inflation pressure is listed as 50-75 psi, not quite what I'm used to with the Continental Ultrasport 700Cx25's on the target Trek 7500 bike with 116 psi, but it might take fast, sharp bumps a little better I suppose. The 700c rim has a label saying "Vigour 2008 Samson Alloy". Appears to be a double-wall rim, tall, almost an aero rim. Daoji put a standard tube with Schrader valve, perhaps it should have an extended Schrader valve, we'll see. Spokes are noticeably thicker and heavier than the "normal" spokes I have on most of my cruiser and road bikes, good news. I hope my multiple spoke wrench fits them. Wheel appears to be properly strung, no up-and-down loping, only a slight side-to-side wobble, very minor. All spokes are tight, probably to a degree proper for such thick spokes.

The hubmotor is black in color, and does not have the three silver bands I've seen in pictures (nor just the one wide silver band some vendors show in their ads) - just solid shiny black. There are no labels or other markings anywhere on the hub motor, except for engraved letters around one rim edge saying HBS-48V1000W09100267 . No manufacturer's logo, no other specs, nada. All the wires come out thru a hollow axle. None of the wires sppears to be larger than about 16ga, not even the ones supplying drive power. Pumping 30 amps thru them during hill climbs could get interesting.

The power-cutoff brake handles and thumb throttle fit the 7500's handlebars perfectly. Brake handles appear to be aluminum alloy, not pot metal as someone reported a while back. They look plenty strong enough to me - and that's from someone who weighs 260# and has been known to lift the back tire an inch or so off the pavement during rapid stops. I found a slight problem in that the thumb throttle's lever sticks out just between the two triggers on the Shimano dual-trigger shifter that came stock on thei Trek 7500. At first I thought it was a perfect location. But then realized the the frontmost shift lever, sticks out farther than the rearmost, and interferes with the thumb throttle lever. Scooting the thumb throttle about 3/4" outboard, mostly solved the problem, now the throttle works thru its entire range and both triggers shift as they should, but that frontmost shift trigger is still tough to reach. We'll see how that shakes out.

The wheel dropped right into the rear dropouts on my Trek 7500 (17.5" men's frame) as though it was desiged for that bike. The hubmotor is actually narrower than the original non-motor hub in the Trek's stock wheel. The flat part of the axle fit perfectly into the dropout slot, a big plus for resisting torque, tho0ugh I will use a steel torque arm too, which I consider a necessity for this 1000W motor. The axle nuts are larger than I'm used to, and actually exceeded the jaw capacity of my 6" Crescent wrench, so I used by 8" which happens to be from China too.

The controller is unmarked - no logos, specs, serial numbers, or anything else, it's completely anonymous. It's in an aluminum case with some very shallow fins. The openings where the wires come out are pretty well sealed against water intrusion by silicon rubber cement, ansd the end plates are gasketed with very thin rubber gaskets.

The kit came with no instructions whatsoever. All the plugs are plugged, in, so I will make a diagram of them before unplugging anything. Still haven't figured out what the red button on the thumb throttle is for, maybe an emergency power cutoff? When you press it once, it goes all the way in, you hear a faint click, and it springs out maybe halfway. Press it again, it goes all the way in, another click, and then it springs all the way out. Pretty clearly a push-on, push-off button. Would have been nice if they'd dropped a piece of paper into the box explaining these things, and maybe with a wiring diagram at least, for inquisitive people who start unplugging things.

My first impression without having actually run it (no battery yet): daoji666 at YXM Corp. designed a good, pretty-easy-to-assemble kit, delivered exactly what was ordered, did a good enough packing job, took sufficient care when assembling the wheel, got the lacing right, and did an overall good job. They are high on my quality list so far.

One odd thing about this rear hubmotor: There appear to be TWO mounts for multi-gear freewheels, one on each side! Daoji put a standard 14-28 five-speed freewheel on the left side, whch is normal (I might replace it with a freewheel that has an 11 or 12 tooth smallest cog, we'll see). Not sure what the screw-on mount on the other side of the hubmotor is for. I've never worked with a disc brake on a bicycle, and this hubmotor doesn't have one. I wonder if that right-side screw-on mount can be used to somehow mount a brake disc? Most bicycle brake discs I've heard of, have a standard-pattern six-bolt mount. But I've heard of a few that have some sort of screw-mount setup. Might this be for that? I don't know, never seen one. We'll see.

So far so good. Now, I wonder when the battery from EP-Battery will get here (shipped Nov. 5 from China, they said. EP_Battery is a different company from YXM, no relation that I know of).

I'll post some pictures soon.
 
The rim sent by YXM Corp. is considerably wider than a "normal" 700C rim, a good thing since an E-bike rim is both going fasterand carrying a heavier load. I had to change the spacing on the V-brakes on the rear wheel to accomodate this - an easy thing on a Trek 7500, just a mattter of changing washers.

The part of the rim where the brake pads actually press, is unusual: Where most wheel rim surfaces are shiny and smooth, this rim has very thin groove running circumferentially. Looks almost like the surface of an old vinyl phonograph record (I might be dating myself here - how many of you are old enough to remember vinyl phonograph records?). I don't know if this will accelerate brake wear or not - the grooves run in the direction the wheel in spinning, so one would think they would simply carve tiny grooves in the brake pads themselves.

Normally I use the front brake all the time anyway, and seldom use the rear. But at the speeds and weights this bike might wind up handling, I may need all the brakes I can get. I may eventually convert the front wheel to a disk brake. At minimum this will take a new hug and possibly a full set of new, slightly shorter, spokes. And maybe if I have brina 1 in my head, I will just hunt up a duplicate of this thicker, wider rim YXM sent me, and the same thicker spokes to boot.
 
Little-Acorn said:
One odd thing about this rear hubmotor: There appear to be TWO mounts for multi-gear freewheels, one on each side! Daoji put a standard 14-28 five-speed freewheel on the left side, whch is normal (I might replace it with a freewheel that has an 11 or 12 tooth smallest cog, we'll see). Not sure what the screw-on mount on the other side of the hubmotor is for. I've never worked with a disc brake on a bicycle, and this hubmotor doesn't have one. I wonder if that right-side screw-on mount can be used to somehow mount a brake disc? Most bicycle brake discs I've heard of, have a standard-pattern six-bolt mount. But I've heard of a few that have some sort of screw-mount setup. Might this be for that? I don't know, never seen one. We'll see.

Yep, that's for a disc brake. Here's what the adapter looks like.

Disc brake adapter.jpg
ebikes.ca sells them as well as others.

Gary
 
Gary, that's terrific news. The brakes on this Trek 7500 have always been fine - excellent, in fact - for a bicycle. But with the higher speeds and greater weight of an e-bike, I'm not so sure they'll be adequate. I'd like very much to put a heftier brake on it, and this now looks like the way to go.

VERY odd that daoji at YXM never mentioned this. I don't recall any word of any kind, that this wheel with this hubmotor, could mount a disc brake. If I had known this, it would have been a MAJOR point in its favor. As it was, I was very close to buying a conhismotor.com motor instead, because it could mount a disc brake, where I thought the YXM motor could not. Even though the conhismotor.com motor has slightly less power and efficiency (on paper) than this YXM motor.

Feels like I'm back in Colorado, rooting for the Broncos when Craig Morton was quarterback. Many touchdowns were scored by the defense, partly because they had a ripping, tenacious defense, and partly because the offense wasn't scoring very often. The prevailing sentiment wheneve they won a game was: "It's better to be lucky than good!"

Here, I don't mind being lucky, turning up an unexpected disc-brake mount!
 
morph999 said:
any pictures?
Ask and ye shall receive.

Target bike (Trek 7500, 17.5" frame, aluminum dropouts). Hubmotor is installed, thumb throttle and power-cutoff brake handles are installed, controller and wiring harness trails all over the place very untidily because I haven't attached it to the frame or done any streamlining or prettifying. Bike came with a spring-suspension seatpost that I had to remove so my wife could lower the seat enough to ride the bike, I replaced it with the solid seatpost shown. Then she lost interest, so I raised the seat high enough for me to ride it, will put the spring seatpost back on soon:
.
 

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Right-side view of the hubmotor, as installed on Trek 7500. Daoji installed a standard 14-28 five-speed freewheel, I may replace it with one whose smallest gear is 11 or 12 teeth. IIRC, the last time I tried to pedal at 30mph with a 14-28, pedals turned so fast I couldn't put any pressure on them. The SHimano Deore XT derailleur is set up for an 8-speed cassette, but I'm leery of an 8-speed freewheel, I've bent axles with them before, and I'm not sure there's enough room. This is a custom axle, of course, I haven't found out yet if I can displace it to the right to allow for a wider freewheel.

This is an outrunner-type motor, as the R/C fans say, the magnets etc. are attached to the axle mounted rigidly to the frame, and the motor shell spins around them. Good news is, the axle is very long on both ends, and I might be able to acccommodate a wider (7-speed) freewheel by using spacer washers. Maybe.
 

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Right-side view of the wheel installation. Note the thick, double-wall rim, almost an aero wheel.
 

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Left-side view of the wheel installation. Torque arm isn't installed, since I don't have it yet, but it will be on this side.
 
Rear view of hubmotor installation, with controller and wiring harness lying sloppily on the ground, shame on me.
 

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Zoomed-in view of rear. I may need to add a spacer between the freewheel and the hubmotor, to keep the derailleur from scraping the hubmotor in the highest gear. We'll see. Might wait till I get the 11-xx freewheel.

Note the shiny aluminum spacer of the left side of the hubmotor, on the axle. Looks like the motor is narrow enough, that there's a lot of extra space, that this spacer takes up. Good news is, there may be room on the right for a wider (7-speed) freewheel, which I can make up for by using a shorte spacer on the left. Bad news is, this would offset the wheel in the frame. Re-tuning the spokes to dish the wheel to the right, could make up for this. But the motor is narrower than a standard bicycle hub, so there may not be much dishing adjustment available. We shall see.
 

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Another rear view, offset slightly to the left to show the axle spacer and that WAY cool disc brake screw-on mount. Torque arm will go here, I don't have it yet. Guess I should have moved the pedal out of the way before taking the picture. Yes, I'm going to put the toe clips back on. Wife hated them, but I don't.
 

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Another rear view, slightly offset to the right. Notice, on the power cables coming out of the axle, the wire-spring stress-relief, a very good idea. Kudoes to Daoji at YXM Corp. Bad news is, it stops short of going into the axle cutout. One-half point off, Daoji. I'll try to move it in, and/or put a few thicknesses of heat-shrink tubing as far into the axle as I can and shrink it tight. If I have to start removing connectors to do that, though, I might just live with the spring alone. Although I do have a bunch of 60-amp connectors and some super-flexible 12-gauge wire coming in from Hobby City along with a Watts-Up Meter.
 

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Right handlebar, a pretty busy place.

Above the bar, gadgets from left to right are a Trek Fusion bike computer that was on the bike when I got it, and the thumb throttle power indicator with red mystery button, probably a power cutoff of some kind.

Below the bar from left to right, are the Shimano Deore XT dual-trigger shifter's gear indicator, then the shift-up thumb trigger (close to you), then the shift-down index-finger trigger with its diagonal lever (far from you), then the thumb throttle tab.

The shift-up trigger is pressed by your thumb, moving toward the front of the bike, which is fine. Shift-down trigger is pressed by you curling your hand and index finger around the bar naturally and pressing your index finger against the trigger, pushing it toward the back of the bike, which works great. The spacing and positioning of the triggers is wonderful for the human hand, which falls on it very naturally and comfortably. Shimano really did a great job designing these triggers.

Until, that is, you slide a thumb throttle onto the handlebar next to them. See how the cable from the thumb throttle comes down just on the other side of the shift-down trigger? Your index ffinger is supposed to get around that cable somehow and press the trigger. Good luck. It's workable, but it helps if you're a contortionist. A twist-grip throttle might be handier here, but dammit, I like thumb throttles!

I also had to scoot the thumb throttle outward about 1/2" so that its tab and the shift-up trigger wouldn't hit each other. They're actually closer than they look in this picture. As a result, I couldn't put the handgrip all the way back on. Notice how the end of the handgrip sort of sags off the end of the handlebar. Sigh. No real design errors here, just a lot of things all on the same handlebar.

I couldn't slide them all in another inch, because of that silly bar welded across the top of the handlebar on this bike. I guess it's somebody's idea of a "stylish" look, or something. The local Trek Superstore had never seen such a bar before. Oddly, my Trek 7700 has one too.
 

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Top view of right handlebar, showing power-cutoff brake handle. I know, I put the right brake handle on the left bar and the left one on the right bar. So sue me. >:p
 

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Bottom view of right handlebar. See how close together the thumb-throttle tab and the shift-down trigger are? Aiee.
 

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Left handlebar with power-cutoff brake handle. There might be room to slide these a little further to the center so I can get this handgrip all the way on.
 

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Tire pressure indication. Looks like good cornering tread. Wonder how long it will last. Note also the tiny grooves in the alloy rim where the V-brake pads will press - I've never seen that before.
 
Tire size, and sticker on the alloy double-wall rim.
 

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Tire brand (Cheng Shin), and too-short Schrader valve stem. If it gives me too much trouble I'll replace it with an extended-stem tube. Another 1/2 point off, Daoji.
 

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Controller (no labels, specs, or anything else) and wiring harness, not yet mounted. Sorry for the messy display, I promise I'll make it much prettier.
 
Battery charger. Normally YXM Corp. sends a lead-acid battery charger with this kit. But I asked them to trade it for a LiFePO4 5-amp charger. They were happy to do so, especially since I agreed to send them an extra $25 for the purpose.
 

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Back of battery charger, with label.
 

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Label on battery charger.

What's wrong with this picture?
 

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Well, that's all for now. Enough? :)

Hmmm, looks like the pics showed up in three ways: The full pic itself in the post, a small version of the pic that you click on to get the full-size pic, and a hyperlink without even a little picture, that you click on to get the big picture.

I have no idea why. If I had my druthers, they'd all be the big picture, right in the post.

Sorry. You'll have to wear out your mouse on some of them.

Also noticed that, on my laptop, the pictures came out nice and bright and easy to see.

But on my older desk system with a CRT, they came out pretty dark, it's hard to see a lot of detail.

Anyone else having such problems? I can brighten them up, praise be to the gods of Print Shop Plus.
 
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