Speed 900s

[maddox10]

A real Speed 900 does 1.1 Nm@12V in stall

[Bodge Job]

Ok, and how much force would it take to drive a robot? Would 2.5 kg of force per wheel be anough?

[maddox10]

Depends on other factors too.

biggerwheels have less roll-resistance, to give one of the variables.

[Bodge Job]

Roll resistance? What is that? And btw, it's 4 wheel drive

[maddox10]

Roll Resistance. (Google it please)
The reason why cars are getting bigger wheels over time.

See the difference between an original mini cooper and the new one. And no, it's not a marketting ploy, but a way to get a little better fuel efficiency without investing big loads of money into more efficient engines.

[Eventorizon]

Would it be overkill to use 2 of these motor to drive a disc, I have more than enough weight spare. And what ratio you typically use with these motors?

[psycho_fling]

its not un heard of

not sure on ratio

[Anttazz]

Drumroll used 2 on its drum originally I think. Also, I think Inertia uses 2 of them to run its disc, so not a bad example to copy

[Eventorizon]

2 it is then, with a combined torque of 2.2Nm it should easily spin a 2Kg disk up to some serious speeds!

[teamshock]

Yep, I use 2 speed 900's on Inertia XL to power the disc which weighs 2kg. Currently on a 4:1 ratio but I am thinking of changing it to 3:1

Seems to work pretty well