HW gear ratio.

[jay]

Just a quick one.

Planning on an 8:1 kart set-up,

24v 750w motors with 10 tooth on the front, 80 on the rear running each wheel.

Does that sound about right?

Thanks.

[Rapidrory]

With 750W motors, you'll probably want to gear it for somewhere around 12 mph; that way you have a fair bit of speed, but shouldn't burn your motors out. 8:1 sounds ok, though it depends on the size of the wheels.

[Eventorizon]

You might find this useful - https://wahiduddin.net/calc/calc_speed_rpm.htm - It is imperial and it does want the radius rather than the diameter which is a pain but it works.

Personally I think 12mph might be a little slow in the new arena which will be much larger than the Live event arenas but its up to you and what you feel you can control when going flat out.

[Rapidrory]

I feel it's more down to what the motors can handle; gear for too much speed and you won't get much pushing power and the motors are more likely to burn out. Acceleration is also a factor; gear too fast and you'll take a long time to change direction and you may not even reach top speed. You need to balance motor power between speed, torque, and reliability for a good drive setup.

[typhoon_driver]

You haven't said what rpm the motors will do.

Technobots has a few handy calculators for these kinds of questions http://www.technobotsonline.com/gear...alculator.html

[maddox10]

Movimotors run around 3000rpm. Some a bit faster, others a bit slower.

Cart tyres are not small, but the difference between fronts and backs is substancial. What size did you have in mind?

Imagine a 10" wheel. 3000rpm/8= 375 rpm on the wheel. Gives around 17 kph.
Overvolt the motors to 36V, and the topspeed goes up to 25kph+

It's up to you, but I like higher voltages and bigger gearratios.

[jay]

It'll just be the sprocket and chain I'll be using from the kart, everything else will be built by myself.
the wheels I'm planning on using are 150mm

[maddox10]

150mm. Overvolting will be a good thing then.

But , 150mm diameter cart wheels, never seen those.


Personal experience, bigger wheels have advantages.

[supernova]

What does the movimotor weigh? The same as a Bosch 750W?

Btw, on Supernova, I used a 8:1 ratio, 250mm wheels, with a bosch 750W at 36V and a 4QD Pro 120. Worked fine but was a tad warm after fights

[maddox10]

Tad heavier, around 4.2 kg as used in Brutus. Heavier body mainly

[supernova]

I didn't know that! that's almost half a kilo heavier per motor then the bosch 750!

[maddox10]

On par with the Iskra's. Those motors use a solid 5mm wall steel tube as motorhousing with ali endcaps.

No taping off the vent holes and so on.

[overkill]

Hi Mario, What model Movimotor are you referring to and how much does it typically cost?

[maddox10]

No Idea and no Idea. It's a 24V version with around the power of a Bosch 750.

[jay]

Hi Mario, What model Movimotor are you referring to and how much does it typically cost?

Not too sure on the model, but the ones ive seen are priced at £180 a pair, so worth a punt i think.