Xcode automatically generates the getters and the setters for you when you define the properties, so you have them already, you can access them like this:
self.speed = 5;
int mySpeed = self.speed;
In case you want to overwrite this setter, you can do it:
-(void)setSpeed:(NSInteger)speed
{
if (speed > maxSpeed)
_speed = maxSpeed;
else
_speed = speed;
}
Take into account that when you use objects, if you implement the setter, you need to release the previous value and retain the new one.