New guy starting a project for son and niece

[Vartz04]

So I am getting ready to start my build. Planning on using a slightly modified version of the spidercarts itzy bitzy frame. My main concern and question is limiting top speed. My niece is 5 and my son is going to be born any day now. I want this thing to be slow. Is there a way to use a jack shaft without using a live axle? Anyone have any pictures of this type of setup? I figure between gearing and throttle limiting I should be able to get this thing to be a 5 -10mph cart.

Any tips you guys could give for building a young kids cart u would appreciate it.

 

[landuse]

Welcome. Yes, you can use a jackshaft on a one wheel kart. I would also not limit the throttle at all. This will fry your clutch because it will never have the opportunity to lock up and will slip.

Have a look at THIS thread for some idea on dead axle jackshafts. It is a pulley, but you get the idea

A dead axle jackshaft will be exactly like a live one except that the axle sprocket is bolted to the wheel using a hub instead of directly onto a sprocket on the axle. That is the only real difference

 

[Vartz04]

Alright that's what I had in my head. Thanks. So I need a 12:1 or higher ratio to keep it sub 10 mph with 10" tires

 

[landuse]

Alright that's what I had in my head. Thanks. So I need a 12:1 or higher ratio to keep it sub 10 mph with 10" tires

Sounds about right

 

[OzFab]

After crunching those numbers in our speed calculator, I get 9mph...

13" tyres with 12:1 gears or 10" tyres with 9:1 gears will give you 12mph...

 

[itsid]

hmm..
for kids that small I'd go for an electric motor set up..

because of several reasons:

a) you can limit the throttle (with a common potentiometer on the throttle lead) and thus limit the speed to anything that's below top speed.

b) limiting the throttle will -as opposed to a lower gear ratio- NOT increase the acceleration.
kids necks are weak.. especially when they wear a heavy helmet.. so yanking them forward might scare them or even hurt them... a 12:1 ratio is a hard push.

c) silent... some kids get scared if a combustion engine screams behind their back,
thus they loosen the throttle (to get rid of the noise) which might disengage the clutch enough to fry it up...

d) when they get older it's nothing but an educated twist with a screwdriver to speed things up again

... that should do for now, but I could go on if you want me to

Oh, almost forgot:


'sid

 

[Vartz04]

Cost wise how does electric compare to a gas setup? Looks like I have some reading to do

 

[itsid]

depends ...

you can buy ev-motors (electric vehicle) in all price ranges, cheapest motor I'd recommend for small kids is a ZY1016 series with 350 Watts.. that can be had for as little as 30 USD
a matching controller can be had for roughly 20-30 USD plus a 10 USD throttle and two 12V batteries...

A my1020 can go up to 1000W and is future safe (still enough power to push a lightweight kart and an adult around)
that's about 100 USD.. the rest remains identical in prices (different controller though!)

So yeah, not counting chain and sprocket (since you'd need that for a cumbustion engine as well) you end up anywhere between 70 USD and 130 USD plus a matching number of batteries, whatever that might be. (the 350W motor takes 24V the 1000W motor either 36V or 48V)
so anything from 2 small 12V motorcycle batteries up to 4 (or more) big 12V car batteries


A 79 predator is ~100 USD a std sized 212 predator 100 with coupon, 120 w/o (if I'm not mistakin)

a clutch is ~30 for any of the two ..

*shrugs*
sometimes you'll find used parts for cheap (Craigslist or ebay etc.)
Last offer I saw (in germany though) was 80 bucks for the complete set my1020 1000W 36V incl controller and throttle (used for less than 1hr)

the best of luck

'sid

 

[Vartz04]

So finding a used electric scooter would be a good option if it's less than $50 ish otherwise it's likely better to buy this stuff new.

I like the electric idea and since I wouldn't need to buy the jack shaft components it will likely be cheaper. Let's say I go 500 watts and it will be young kids on a light cart. Will I have issues running this in the lawn? I assume the torque of electric motors with decent gearing will let this go anywhere the 79cc predator would?

 

[itsid]

since the electric scooter comes with a nice batpack that's at least good enough for testing and some quick runs in the yard.. maybe slightly more.. but yes.
keep in mind though, that you add a pedal throttle to your list, since the scooter will come with a twist throttle.

lawn is difficult to judge, how's the soil beneath it.. soft, muddy, firm, even, rugged ?
on a more or less levelled and firm surface though, you shouldn't have any problems at all using a 500W motor.

but no, a 500W motor can do most, but not everything a 79 predator can,
the predator will (assuming again the low ratio to limit the top speed) have more torque,
maybe even enough to push that small kart up an insanely steep hill.
The 500W motor can't..

'sid

 

[Vartz04]

The hill will be the issue. My parents house would likely be where this gets used quite often (2-1/2 acres ). Starting out I'd likely restrain the kids to the flat front yard and driveway (huge. Driveway ) but the backyard is one big hill down to a pond so as they got older and better at driving there going to want to go up and down that hill. Good for thought anyway as the general cart build is the same either way I go except for the motor mount location so I'm set to go ahead and get going on the frame. Either way it will be a slow build and I'm in no hurry really because my son isn't even born yet and my niece doesn't even know I'm building it. I've got 3-4 years to work out any kinks before my kid will even get to drive it

 

[Vartz04]

Well got the frame mostly welded up today. I really need more practice on my fillet welds. Ground the welds mostly flush on the top and bottom to make putting on a floor pan and other brackets mounts ect easier

Frame is 6" longer than the standard itzy bitzy to help "future proof" it I'll be putting some cross rails in that I can mount the seat to that will allow for adjustment.