Besides “eyes up” “smooth is fast” is the next most common advice given to drivers. I am well documented and on-the-record (read Optimum Drive!) for dismissing “eyes up” as lazy coaching (since it is a symptom, not the actual problem). I have nearly equal contempt for the overuse of “smooth is fast”.
You end up having the same issue every time you try to summarize something as infinitely variable as driving. People tend to apply it to everything unless they are given context and the fact that they are asking in the first place meant they are not at a level to process the context, they aren’t ready. That all but guarantees they will misunderstand and misapply the advice. If that stops them from overdriving that day and potentially crashing the car it’s probably a tradeoff worth making but if they always apply it from that day forward it over time becomes a mediocrity trap.
I coach people all the time that are a second or two off and are very focused on being smooth. What are the signs? Pinching radiuses and progressive braking are the two that really jump out on the data. When giving a hot lap or doing a data overlay they will be shocked at the relative violence of the brake application and the initial rate of turn (yaw rate) fast drivers input into the car. Those two things get you a ton of time. Neither feel very “smooth” (they are though relatively to the tire and that’s what matters). It just needs to keep the tire hooked up, your inputs should be (at turn in and brake application) right at the limit of what the tires car accept without sliding. If you are ever building to the limit you are losing time so a smooth brake application will cost you brake distance and turning in smoothly you are costing yourself radius (a fast turn in gets you a bigger more constant radius…think curve on the bottom of an egg vs. slow progressive turn in where the radius looks like the top curve on an egg which will result in lower mid corner speeds).
“Smooth is fast” is more in the context of a car (tires) on the limit already after the brake application or turn inassuming we have the car balanced right at the limit that is where and when the platform demands a delicate touch, when done correctly, there is no extra available grip so it is all give and take to optimize the car as we go. This is true of the relationship between brake and steering and steering and throttle…this is where the smoothness counts. When you think of the brake application or turn in the tires are not at their limit which is why we don’t want or need to be “smooth”, we want to get the tires to their limits as quickly (and as accurately) as possible. Anything less than that is simply time lost.