is there some reason i can't use electric skateboard parts to make a micro kart?

i want to build a micro kart. i have assorted skateboard/longboard parts left over from my hobby of longboarding including several full sets of wheels, it makes sense to me to use these wheels on my kart rather than buy entirely new wheels but i don't want to drill holes into them for drive sprockets as i want to be able to use them for boarding too and perhaps sell them on later. I've looked about and found 1 company that make adapter sprockets in a variety of tooth counts that fit through the existing holes in the cores of some of my wheels but they only fit their own mounting kits for electric skateboards using the same motors and ESC's as i want to use for my kart . iv emailed them about my idea but they seem to think that it won't work because i want to accelerate from a standing start instead of pushing off like on a conventional skateboard. im confused by this because while i understand their concern i can't find a single video of their product in use on a board that requires a push start, every demo video i can find involves the rider standing on a stationary board and then accelerating from a standing start using a remote control trigger.
Assuming i manage to build a kart with the same weight as a fairly chunky electric skateboard, surely my being in a sitting instead of standing position shouldn't make a difference to the operation of a vehicle which doesn't require the push start they seem to think it does...?

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your answers you got are well thought and intelligent. unfortunately I don't think there sk8ers or totally familiar with eboards. talk to the owner at metroboard his name is llan sabar . dude went to mit and quit corporate America to build eboards. he can make one out of any spec you send him regular street boards too. He really cares too. not bout the buck to him but thrill of the ride. metro-board.com my husband has had a gas and electric

he can answer your cart questions the best

I had to do some motor works for a company in my early years and if torque is the main issue here there might be a different approach.

For very high torque applications with limited space for big motors we used high speed motors with a reduction gearbox, sometimes even planetary gearboxes as a stacked system.
That way for example, a small winch system was built capabale of pulling over 500kg with motor and gearbox that was fitted into a 80mm PVC pipe.
Basically work out the RPM's you need at the drive train for your kart.
From there you check what reduction gearboxes are available that can handle the troque you need on the drivetrain.
Let's say you would need 250RPM at the drivetrain for your max speed.
With a 10.000RPM motor a 40:1 reduction gearbox would do the trick.
You have to find the right balance between size of the gearbox, motor speed what the gearbox can handle as the max input RPM's.

On our winch project a 6V motor with 28.000RPM was used on a 256/1 gearbox, driving 10mm shaft to roll up the line.

rickharris2 years ago

https://www.instructables.com/id/Building-an-electr...

You will note this car is capable of 30 MPH on the flat with a 500 watt motor drawing 20 amps from 2 car batteries (around 70 A/hr)

SO. Your RC motor has a relatively low speed. 130RPM per volt. Lets assume you get a 6 cell battery at 6000mA/hrs

6 * 3.7=22.2 volts * 130 = 2886 RPM.

BUT your motor has very little mass and so little torque. Adding gearing will increase the torque.

Say your wheels are 2 inc in diameter - so 2 * 3.142 = 4.284 inchs traveled every time your wheel turns 1 REV.

63360 inches in a mile.

63360/4.284=14789 revolutions of the wheel to go 1 mile.

1 mile in 1 min = 60 MPH. lets assume you want to go 15 MPH so 1/4 mile in 1 min=14789/4=3697 RPM at he wheel.

From this you can see you need to gear the motor UP and so have even LESS torque.

Our car, weighing around 160/180 pounds would NOT self start with a 500 watt motor with the gearing we had to reach 30 MPH.

Your motor isn't big enough.

Look at existing scooters you will see much larger motors often operating on 24 volts.

Ebay is a good source.

ambientvoid (author)  rickharris2 years ago

mine only needs to travel at or under 5mph most of the time with very occasional bursts of speed up to about 15mph, the combined weight of me and the kart would probably be about 265 pounds, the wheels are 3.5 inches diameter. i tried working out the sums myself but my brain stops working on hot days -_-

Slower is worse. Look at what others have done. Do the maths.

Looking at the link above perhaps it will work. You can buy a kit $400 or buy the parts you need.

Build it and show us. Personally i hope you can get it to work as I have an application for something similiar.

ambientvoid (author) 2 years ago
SA0072 years ago

It could be that the motor used is of a brushless variety.

That way if the motor controller 'starts' the motor it does not know the position it is in and that positon could be at a 'dead' point where the motor does not provide power.

This is solved by rotating the motor a bit, on a skateboard that means moving your feet and/or weight a bit, on a kart that could mean getting out and moving the cart.

irishjim682 years ago

Weight is definitely going to be your biggest issue with this project. Those electric motors are designed to operate with a specific starting load range (the load on the motor when power is applied and it wants to begin turning). That load range is derived from the rider weight range + vehicle weight. Increasing either factor will result in a greater starting load on the motor which could result in burned motor windings from excessive starting current attempting to travel through the motor at the standing start. While your project plan is not impossible, you should build out your cart in order to get an accurate weight of it, then you can plan the appropriate propulsion unit for it. Good luck with it, and make sure to post the build here!

If in doubt you can always upgrade the motor and batteries.
On a kart you not soo limited with space.
With most motors a bigger battery is enough if the overall weight is not much more that the skateboard design.

ambientvoid (author)  Downunder35m2 years ago

yeah except the sprocket adaptors they make are designed with specific motors in mind, they do different sprockets for different motors but not for all different wheels and only guaranteed up to a certain size/power, i could upgrade the batteries but im not sure i can do much about the motors. i mean i could risk it but if it goes sideways then that's more money i can't afford down the drain...

Chances are your not going to be able to keep the cart weight down that much. The cart will likely weigh a decent amount more and that is the issue. What are you planing to build the card out of and what dimensions are you thinking?

ambientvoid (author)  mpilchfamily2 years ago

not totally sure yet, most likely extruded aluminium or some kind of lightweight metal tubing. whatever i end up using the major requirement is its being light enough for me to carry or at least pull along by hand. I'm still messing around with different design ideas but it needs to be as small as it can be, i've been looking at some of my longboards for sizing ideas and at the moment i'm thinking roughly 20" wide (excluding the wheels) and 3ft long with a 2ft long T bar off the front to double as both foot rest and carry/drag handle. i'm thinking either a foam block or a canvas sling for use as a seat to keep the weight down...

ambientvoid (author)  ambientvoid2 years ago

I've considered 'borrowing' the canvas seat from my kite buggy and building around that so that the seat is slung nice and low but the kart might end up too wide so i'm not sure...