Does my brand new hub motor (Aikema AKM-128CST) have a bent axle? (4K video)

[Comrade]

Are you going to order another side cover?

Most likely. I spent $8 on a freehub removal tool that's coming from China. I'm not in a rush. Winter is coming. The tool's dimensions line up perfectly with the AKM freehub. So I think it's pretty much a standard freehub mechanism.

Should be interesting to actually figure out the cause of such a severe misalignment.

 

[Comrade]

So here is some info for the future generations (or if I forget :lol...

The removal tool that worked just fine is this.

Name: Tower Base Tool
Weight: about 182g
Material: Stainless Steel Anti falling device + 45 steel sleeve
Screw length: 15.6cm
Tool outer diameter: 28.5mm
Width of card slot: 4mm

Purchased on AliExpress. Search string "Bicycle Flower Drum Tower Base Removal tool Universal 4mm slot installation sleeve for Mountain Road bike Cycling tools". $7.52 shipped to USA.

Quality of the tool is top notch. It's probably not very high quality hardened steel, but it is way overbuilt for the task.



The freehub tower was indeed glued into the side cover. No idea why. Turn counter-clockwise to loosen. Chain tension would always keep it tight.



Once cleaned up, the threads look perfect. Very nice tight fit.



To disassemble the ratchet mechanism, grip the side cover in a vise, but now turn the removal tool clock-wise (reverse thread), and that will remove the outer bearing cup.



And there is significant runout on the inner ball bearing race. So it is basically not perfectly perpendicular to the aluminum side cover.

No idea how they got crooked threads on a machined part.

 

[calab]

You could not even build that tool at home with new parts for that price the threaded rod alone would be the price of the tool.

 

[Comrade]

You could not even build that tool at home with new parts for that price the threaded rod alone would be the price of the tool.

At least 50 middlemen made a profit from the time that rod comes out of a Chinese factory to when it makes it to Home Depot. I bet at least a third of that $7.52 was shipping too. :lol:





There is 0.2159mm of runout on the bearing race.

Looking at the picture of the side cover in the vise, I wonder if I can use a small shim to put some pressure just in the right spot to bend the center of the cover to make it perpendicular.

 

[Oli.Hall]

Looking at the picture of the side cover in the vise, I wonder if I can use a small shim to put some pressure just in the right spot to bend the center of the cover to make it perpendicular.

The motor shells and side covers are made from die cast aluminium which is very un-malleable and does not respond well to bending. It is possible to machine die-cast aluminium with high speed machine tools, but it does not respond well to to any kind of manual cold working and it will tend to just crack. You may get lucky with it, but I wouldn't try it personally as I'd be a little worried that it could crack in use when I was pressing hard on the pedals, and it could either cause an off, or cause some unwanted soft-contact with the top-tube!!

 

[Comrade]

I have a new side cover on order. Nothing to lose by trying it. :lol:

If the runout is 0.2159 mm, I just need to bring one edge in by 0.1079 mm. The thickness of a single strand of hair. It does look much more serious than that in my own video. Maybe I should measure each one of those balls in the bearing.

 

[Comrade]

Put the new side cover on, and it's as smooth as can be. No visible or measurable runout. :thumb:

While taking the motor apart and putting it back together I noticed all 6 of these bolts holding the core together were not only loose, but some even came out a few turns. On a new motor that only spun a little in a test stand.

No threadlock at all. Planned obsolescence is getting out of hand. :lol:

 

[Chalo]

While taking the motor apart and putting it back together I noticed all 6 of these bolts holding the core together were not only loose, but some even came out a few turns. On a new motor that only spun a little in a test stand.

No threadlock at all. Planned obsolescence is getting out of hand. :lol:

The unusual cyclical movement may have walked the screws out of their threads, when it wouldn't have happened otherwise. I doubt there was any obsolescence planned. That's an American idea anyway. Chinese manufacturers just make stuff that doesn't last very long, so there's no opportunity for it to become obsolescent.

 

[eanp]

just a quickie to say what an excellent thread guys....well done to all!