The Speed achieved by a vex starter kit

Im looking to have my robot go about walking speed (1.34 m/s // 4.82 km/h). So if possible can someone let me know if that speed is achievable by the kit…


It depends, how big is the rest of robot and how much does it weigh?

Walking speed across a perfectly flat carpted floor?

oh yes, i’ve had robots achieve about 11 mph. it took some extreme gearing (1:7!) and made the motors really hot (luckily i was using the clutches back then) but yes, it was achievable. try to make it very light, as simply as possible, and go for a 1:3 gear ratio (36 tooth on motor, 12 tooth on driven axle). that will probably go 5 mph.

If you are just using the starter kit, it is possible, but not convenient (or more specifically it is hard on the motors.) I recommend using at least four motors though. Put both motors on one axle with a 5:1 gear ratio and you will have a fast robot that is still powerful enough to move small furniture. Use large wheels for an additional spped boost and better traction without any significant torque loss.

Those two suggestions are why all of our living room chairs have vexbot-level scratches on them. :slight_smile:

At such gear ratios, it will be important to ensure gradual ramp up of the motor power. Do consider gearshifting as well.

5:1 is a reduction, so it’s kinda slow, unless you mean it will still be relativley fast for having enough torque to push small furniture. 5:1 mean the motor will spin 5 times for every time the driven axle spins once. sorry if you meant something else, i’m just a little confused with your wording.

Thanks so much for the input guys, I really appreciate it. Weight is not a problem, achieving that speed is my main priority, but ye again thanks alot.


For clarification, use a 60 tooth gear on each of the motors and connect both of them to the same 12 tooth gear. I was under the impression that gear ratios were given as

driving gear (the one connected to the motor axle) :driven gear

and gave the ratio I was thinking of in that format.

yeah, most people on the forum seem to think that…

As well as the documentation in the VEX 2008 Inventor’s Guide Complete, PDF Pages 61-63 (Inventor’s Guide Pages 3-5 to 3-7 ).

lol looks like they got confused in the making. when they said about 1:25, 1:1, and 1:3 they were right, but the 5:1 part was wrong. now i see why lots of people think that…