please note that Webots 7.4.3 is no longer supported.
I would suggest you to upgrade to the latest version of Webots 8.
If your wheel touches some other objects like a floor, then you have to remove the contact friction using the ContactProperties
Otherwise you have to check that your JointParameters
node doesn't specify any friction, damping, etc. and that the Motor
node 'maxTorque' and 'maxVelocity' are big enough for your purposes.