The motor and pulleys

You want an outrunner brushless motor (they have a tremendous amount of power).

The number one thing when looking for an outrunner brushless motor is large size motor with the lowest kv motor possible. To get revolutions per minute you multiple the kv by the volts to the motor. Hence think of kv as RMP.

You want a kv below 300kv but preferably around the 200kv mark. Why? You’re looking for torque/power not high speed. You can always gear it higher to get more speed but you can make a high kv motor perform better at low speeds. When you think about it you way much more you weigh than the average RC car.

Basically any largish (above 50mm) brushless outrunner motor http://www.hobbyking.com/hobbyking/store/__1218__517__Electric_Motors-Above_50mm.html

 

Basically any largish (above 50mm) brushless outrunner motor http://www.hobbyking.com/hobbyking/store/__1218__517__Electric_Motors-Above_50mm.html

Here are some that will work.

Also the guys selling kits have got their own motors these days. All are lowish kv motors of a similar kind. This one for $90 include a Hall sensor isn’t a bad price http://diyelectricskateboard.com/diy-electric-skateboard-kits-parts/electric-skateboard-motor-6355/

Ticks for new players:

  • Trying to get a board that goes super-duper fast. And buy a motor with a high kv – you idiot. You’re starting a zero. 25kph feels fast on a skateboard.
  • Buying the motor with the highest watts – why? KV matters. These brushless motors have so much power

How brushless motors work (short answer, like a computer timed fuel injected motor): https://www.youtube.com/watch?v=ZAY5JInyHXY&ab_channel=digitalPimple

Hall sensors for motors

A hall sensor isn’t necessary and 99% of electric skateboard don’t seem to include a sensored ESC/Motor ( I didn’t). However, hall sensors are sensors that tell where the motor is in the rotation.  Theoretically they make the board have a smoother start, I’m  told that they’re more useful in higher speed motor applications however, I’m no expert. If you’re interested in the topic look:

http://www.electric-skateboard.builders/t/why-are-sensored-setups-ignored/1497/6

http://e0designs.com/products/hall-effect-sensor-board/

https://howtomakeanelectricskateboard.wordpress.com/2014/06/22/marbel-kickstarter/

How do you calculate the speed of your electric skateboard

Check out my post here: http://howtomakeanelectricskateboard.com/uncategorized/calculating-speed/

Don’t go aiming for some high top speed because you think you’re kool and will be bombing it at 100mph, remember you’re going to spend most of your time going from 0 -15kph. Also lower kv(RPM)  motors mean they’re design to pull at those lower speeds..

**Buy the lowest kv motor, you knucklehead. i.e. less than 300kv **

The Pulleys & Belts

For belts and pulleys I’ve found this to be one of the most comprehensive sites to purchase all those little thing (if a little slow with international delivery). https://sdp-si.com/eStore/Catalog 

(While this site has an awesome selection I have to say the website itself makes me want to smash my head against the keyboard, there is that much stuff on there it is sometime hard to find)

Belts:

For belts most people choose a HTD 5mm teeth belts either 9mm or 12 mm wide. HTD belts have been designed to withstand loads. (Yeah I said millimetres, deal with it you crazy Americans. PS. For the love of spaghetti monster stop it with the imperial measuring system. USA, Burma and Liberia got it wrong.). Most setups I’ve seen are using a 9mm belt. Link to the lengths here: http://www.sdp-si.com/products/belts/htd5.htm. If I had my time again I’d probably go for a 12mm but it seem to be a little harder to find parts as most are going to a 9mm setup. Including myself.

Small pulley:

The motors above have a 8mm bore. So figure out how many teeth you will need use the speed calculator above but 15 teeth should be good. e.g:

  • Part Number: A 6Z25M015DF0908
  • 5 mm (HTD) Pitch,15 Teeth, 8mm Bore, Aluminium Insert, Polycarbonate Timing Pulley for 9mm Wide Belt
  • Anywhere from 15T to 18T is about right

Large pulley:

This needs to attach to the wheel. You can pick yourself a pre-made piece from one of the kit website or you can purchase a large pulley and fix it to the wheel. To do this I used large bolts that threaded through the cogs of the Abec 11 wheels. Don’t forget a large washer on the outside and lock tight because from my test they wanted to undo themselves.

If you have access or want to get one printed check out thingverse: http://www.thingiverse.com/mahmuodmasri/collections/skateboard

SPD-SI link: https://shop.sdp-si.com/catalog?cid=p347&filter=a0:2:5%20mm%20(HTD);a6:2:40;a2:2:Polycarbonate

Pulley size: You’re looking at anywhere from 30T to 40Teeth. Mostly about 36Teeth

Overall, you’re looking at a ratio of about 2:1

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