Indoor Bay or Outdoor Grass?

Ask ten fitters whether indoor or outdoor testing is better and you will get ten confident answers, roughly half in each direction. That is a good sign that the question is wrong. The two environments are not competing versions of the same test. They measure different things, and the value of a session comes from knowing which one you are relying on at any given moment.

What Control Buys You

An enclosed bay eliminates variables, and that is not a small thing. Temperature holds steady across the session. There is no wind to explain away a bad result. The mat presents the same lie on the fortieth shot as on the first. The launch monitor sits exactly where it was calibrated, at a known distance, on a known surface.

Every one of those constants matters when the question is comparative. If you want to know whether shaft A produces a tighter dispersion than shaft B for you, the only way to get a trustworthy answer is to hold everything else still. Outdoors, a gust arriving during shaft B's block quietly ruins the comparison and nobody notices.

This is why the narrowing stage of every session we run happens indoors. Going from a wall of options down to a short list is a comparison problem, and comparison problems want control.

What Control Costs You

The trouble is that the same constants are also fictions.

A mat is the biggest one. Hitting a shot slightly fat off a mat produces a perfectly acceptable result, because the club skids into the ball instead of digging into the ground. The same delivery into Bermuda in February produces a chunk. A golfer fitted entirely on a mat can be handed a sole grind that the mat forgave and the fairway will not, and every wedge fitter has watched this happen.

The second fiction is carry distance. Indoors, the ball hits a screen after eight feet. Everything beyond that point is the software running a flight model — a good model, usually, but a model, which means it is making assumptions about air density, temperature, and spin decay. Those assumptions are usually set for standard conditions rather than for a humid Savannah afternoon.

The third is subtler and has nothing to do with physics. Some golfers simply swing differently indoors. Knowing that the ball will hit a screen in eight feet removes a certain amount of consequence, and consequence changes tempo. It is not universal, but it is common enough that we watch for it.

What Grass Buys You

Outdoors gives you the two things a bay cannot fake: real turf interaction and a ball that actually flies.

Divots are data. Where the club enters the ground, how deep it goes, and whether the entry point sits ahead of or behind the ball tell you more about whether a sole design suits you than any launch monitor reading. The same is true for how the club behaves out of a lie that is not perfect.

And carry is measured rather than modelled. Whatever the air is doing today, the ball has to fly through it. On a breezy afternoon this frequently separates two shafts that had been posting nearly identical indoor numbers, because a lower-spinning flight that looks efficient on a screen can get knocked down hard when the wind gets under it.

What Grass Costs You

Everything moves. The wind changes between blocks, so shaft A and shaft B were not tested under the same conditions unless you deliberately alternate them. The lie is different every shot. Light and background make ball tracking less reliable for some units. And a golfer's warm-up state drifts over a long outdoor session in the heat.

Outdoors is a poor place to make a fine comparison and an excellent place to sanity-check a decision you have already made.

How We Split It

1. Baseline block indoors with your own club, so the reference is captured under controlled conditions.
2. Narrowing indoors, one variable at a time, until two or three candidates remain.
3. Confirmation outdoors on real turf, alternating candidates rather than testing them in separate blocks, so a change in wind hits both equally.
4. Decision, weighted toward the outdoor result whenever the two disagree.

That last rule is the one that matters. When indoor and outdoor results conflict, we go with outdoors, because that is the environment your golf actually happens in. The bay's job was to get us to a short list honestly, and it did that.

If You Only Get One

Plenty of fitting studios are indoor-only, for perfectly good reasons — land is expensive and weather is unreliable. If that is your only option, it is still far better than no fitting at all. Just know which conclusions to hold loosely: absolute carry numbers, wedge sole recommendations, and anything involving how a club behaves out of a bad lie.

And if a fitter tells you indoor data is identical to outdoor data, that is a useful thing to have learned about the fitter.