10mm motor shaft but 8mm pulley gear

I have ordered some 6368 190kv motors which have a 10mm shaft but I have 8mm motor pulley gears.

Has anyone drilled out the bore of a gear before or filed down the shaft of the motor to 8mm?

Anyone know where I can pick up 10mm bore 5M pulleys in the UK?

Any suggestions for what teeth number to go for? Using Slick Revolution wheels with a 36T pulley on 10s3p batteries.


Unless you have a lathe i dont recommend making it wider. Buy a new pulley. Its like 2-5 euros. 1:3 in gearing is nice if you have a single motor build.

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I forgot to mention this will be a dual drive build.

Any links to websites?

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If you have a drill press then drilling pulleys is no problem. Drill press or buy 10mm pulleys.

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Both carry 10mm bore in multiple teeth counts

I have tried to bore out a motor pulley before. It is very difficult without a lathe and did not work well. Unless you are desperate, I would recommend something else.

I would recommend buying new pulley’s because I had the same issue. I drilled the pulley out with a drill press and that worked out for a few rides, eventually the pulley just shattered.

You can buy from eskating.eu if you are from eu and I have bought the pulleys from here: https://powge.nl.aliexpress.com/store/all-wholesale-products/702327.html?spm=a2g0z.12010615.0.0.371c6f35plbqSS

My pulleys came with no bore at all…

If you have access to a lathe or know some one who does, no problem. If not, its hard, but can still be done if you can use a drill press. First, you need a good drill press, none of that wobbly misused abused and unmaintained equipment. Also you need a weird size of drill, DO NOT use 10mm, as the hole it leaves will be closer to 10,1 mm and your pulley will be pretty much useless. Drill the pulley with 9,5, or better 9,7 or 9,8mm drill, then you need to use a reamer to finish up the hole and bring it to 10mm.

Now that I wrote that, if you have access to a good drill press and reamers, you probably have a lathe nearby too… You can probably just buy a new pulley and save yourself the time

2nd @xilw3r

Thanks guys, just went and bought new gears instead!