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.
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 brain 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.
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? Today a friend told me that that is what it is: a screw-on mount for certain brands of disc brake. And he showed me an adapter that screws onto it and provides the standard six-bolt pattern that most present-day bicycle disc brakes have. 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.