New to RC need a Servo but not sure what to get
 

Not sure where this belongs but hopefully it is in the right spot.

I am building a large RC "Vehicle" for a Maker Faire in my town. It will be an entertainment center with a television in it. I have roughly estimated that it will weigh about 250 lbs. My problem is finding a servo to drive the steering on the front wheels. I am unsure how to calculate the torque required to turn wheels under that pressure in a reasonable amount of time. I am trying to do this as cheaply as possible so I don't want to pay for more power than I need, but I also don't know where to begin. So with that in mind, does anyone know how to figure out the torque required, and also if possible a motor that would fit my needs? I'm sure you'd need more variables for the device, but I am not yet sure what is needed, so if you want clarification ask away.

I doubt you'll find a typical "RC" servo that will do this job. And even if you do, the price may frighten you off. I see two options for you.

1. Have some kind of power steering system to take the load off any servo.
2. Contact the various servo/radio manufacturers to see what they have to say. Most of them are quite helpful to questions. But not all.

Servo City has what they call servo gear boxes. A large servo with an even larger gear set. Massive torque but travel/rotation time is now measured in seconds. Another possibility from them is a linear servo. You can see both of them here:

Servo City

That's going to require a lot of torque, you're better off looking to a linear actuator. We have 2 servos that might do the job if they were setup in tandem, but the price starts out at $500ea. This might get more complicated than you are really wanting it to.

Google "Seiko" RC Servos.
Also, instead of using one servo, you might be able to do the job with a servo on each wheel, at less cost!