Do the strong and weak nuclear forces also travel at the speed of light? Among the four fundamental forces, it is now pretty well-known that the electromagnetic and gravitational ones travel at the speed of light.
How about the other two (strong and weak nuclear forces)? Does it even make sense to talk about their speed?
 A: Massless ones travel at speed of light, massive ones slower, weak force carriers have mass, strong force carriers don't.
A: In theory the weak and strong forces both have infinite range, but the potential is a Yukawa potential which falls off exponentially with distance, instead of the $1/r$ potential of gravity and electromagnetism. The question of how they behave at long distance is purely academic because in practice they're unobservably weak beyond a few femtometers for the strong force or attometers for the weak force.
What propagates at the speed of light in the case of electromagnetism and gravity is "updates" to the field configuration, not the field as such. A perturbation of the charge creates a wave that propagates outward at $c$ from the perturbation; before that wave passes the field is in its old configuration and after it passes it's in its new configuration. The update of a Yukawa field would be a more gradual process because the waves can propagate at arbitrary sublight speeds. However, the leading edge of the update would still propagate at $c$.
