Pulley Keyway EU/NL

Hey guys, i bought a pulley with keyway but aparently it didn’t come with the key, which usually happens right, soo anybody has one for me or knows where to buy one in the NL or EU

Skip the key and use strong threadlocker on it instead.

what… thread locker is not strong enough to hold a pulley in place. I’m assuming you’re telling him to jam the grub screw into the keyway and threadlock it. That’d work, but is less elegant.


Lots of guys who only use thread locker. @rich for example :grinning:

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Well my main board just uses a bit of TL-609 no screws on the pulley it has yet to come out after 200 - 300 miles now.

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I could do a grubscrew in the keyway slot actually but offcourse prefer to use the keyway as its intended but if its to much effort for me to get a key ill just use the screw instead i think

does it have flat spots on the shaft?

Its the flipsky 270kv might upgrade tho, its round and has a keyway

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Nope, round shaft.

@okp also has some keyways :smile:

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If you have a keyway, use it. Keys are the best possible way to lock a pulley to a motor.


Keyway and key is king if they fit (but mostly need modifications). The most important is that there is no play of the key in the keyway of shaft and pulley.

First insert the key, then slide the pulley on the shaft (without tightening the grub screw). Move it left and right and see if there is any play, when the pulley wiggles find out which keyway is too big. Add e.g kapton tape (0.04mm) until the play is gone. Once I had to add even thick fishpaper. This takes some time but saves worries. Then add medium strength thread locker (e.g. Loctite 243) on the grub screw and tighten it, wait 24 hours to let it cure.


If the pulley wiggles the grub screw comes loose very often from accelerating and braking. With APS pulleys it’s a bit better because the grub screw is on the key.

I had various motors from 4 different brands and only once it was a perfect fit with APS HEV motors and their keys/pulleys. I was in a hurry and didn’t add thread locker on the tiny M3 screw, it hold over 2 weeks daily riding. I had pulleys which were coming loose after every ride no matter how much thread locker added. The worst fit ever was with APS 6355 and APS pulleys/keys (all ordered at once). The keyway in the pulleys were to small for the keys so I wrote Bruno if he could send me the correct keys. His answer was “file down the keys”. Well, I did it and added kapton tape against play. BTW the best and most accurate keyways are in the E-Toxx gears from @Nowind, so only kapton tape for the shaft.

Damn, this post is getting long, just wanted to say my opinion about keys :laughing:

And my last sentence to this topic: NEVER use a standard allen key for the grub screw or anything on your esk8 :wink:

I’ve always used key and keyways with Loctite 243 on set screw on pulleys and gears. Once I put additionally a bit retaining compound on the key and the pulleys hold great. But removing wasn’t easy even with a blowtorch because of the key, it was kinda locked. On my MTB with helicals I use Loctite 638 only, no key, no grub screw.


I put a single layer of kapton on each side of the key to help with this, but this seems like a better solution!

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Do you mean the fishpaper? :laughing: I was curious and just measured the thickness of my fishpaper, it’s 0.23mm, that was a huge gap between key and keyway.

Good point and much better than 2 layers on one side. If the keyway is too big in the pulleys it takes so many trials because the pulley crush the kapton tape while sliding on the shaft. This was my biggest problem.

Yea I had the tearing of kapton when I did it as well. I had to “wiggle” the pulley on carefully to avoid tearing, but threadlocker seems much easier.

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Up to the moment you need to remove the pulley/gear :laughing: which I have to do soon :fire:.

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