Torque needed for tug a war comp bot

I am building a tug a war competition robot and was needing to know how much torque we needed since I keep changing it and see no changes


When you say you are changing it, do you mean you are changing the gear ratio or you are changing the max torque block in VEXcode?

changing the gear ratio is what i mean

I’m not entirely sure how you wouldn’t see the difference in speed and torque. Are you making compound ratios? Could you send some pictures or videos to show us what you have?

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i am making compound ratios and sadly I can’t send pictures Sorry

Well, it would depend on the robots that you have to fight. In order to win, a higher combination of torque and traction is needed to best your opponents.


Sound like you don’t have to turn so I would go with 8 traction wheels with direct drive with 8 100 rpm motors and 20 pounds of extra weight to make sure your 8 wheels stick to the ground.


at one point, which you have likely reached if you are using compound ratios, the traction your robot has with the ground will likely be your limiting factor. Try experimenting with different wheel types to see which is the grippiest. Also if you don’t have a limit on motors, you could try adding ballast to your robot to keep the wheels gripped to the ground.

I’m assuming this is for iq based off of the category, I don’t know much about iq but I do know that the motors are relatively weak, so using as many motors as you’ve been allowed is a good idea.


Are you tugging against other Vex IQ robots? If so, then the best gear ratio really depends on the gear ratios of the other robots. We did a tug-of-war as part of a Drivetrain Challenge a few years back. The best tug-of-war robot at our competition was a five motor swerve drive, with a one-to-one gear ratio and 200mm tires. It beat out the “Power Turtle”) robot because it weighed more and could get better traction. The Power Turtle had a 1x3 gear ratio and small 160mm tires. But it was too light and ended up skidding as it was being dragged.

Once you get to a certain point, the weight becomes more important than the gear ratio. Of course, there will be a limit on that too. The final limiting factor will be the available power in the battery. Because of that, having more than four motors may not help. 9935E is probably joking, but moving 20 lbs with an IQ robot doesn’t seem possible. But then again, if no one can move your 20 lb robot, then you can’t lose.

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I thought it was vrc. I was not joking about the 20 pounds. 8 100 rpm motors can so that easily. Actually just making your robot unmovable is a pretty good idea.

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If you have worm gears, they can give very high torque and they can not be driven by the wheel rotating backwards. In other words, they will lock and as long as you have weight and grip with the tires, they can not pull you backwards. It will crawl very very slowly though. Your standard gears can turn the motor in the opposite direction meaning that your competitor could potential over power the amount of torque made by your motors. One problem might be the supports to breaking for the gearbox though.