Big issue with fitting driver inside

I discovered something yesterday that was wholly unexpected, but nonetheless very real. While I’m not an advocate of being fit for clubs inside, generally, I am now wholly opposed to the idea for drivers, specifically.

A buddy of mine has a full simulator bay at his house with a Trackman 4; he has more than enough space for it to operate indoors (11’ from TM4 to the ball and 15’ from the ball to the screen. Yes, I know, TM4 is not great indoors for ball flight, but I’ve never heard any complaints about club data indoors, and that is where my issue came up.

I am generally a 110-112 CHS with driver and low 90’s with 7-iron. Today, in his studio, my 7-iron was between 91 and 93, which is where I would expect it to be. However, on 50 driver swings, the highest I could get was 98, though my path, face, and AOA numbers were similar to what they normally are. I don’t doubt the accuracy of the readings, but something about swinging inside with a driver clearly affected my ability to let it loose. Just to make sure it wasn’t my swing, we walked out onto the course and went to the driving range. My first three drives, using the same exact TM4, were 109, 112, and 111. I took a total of 20 swings outdoors, and my average was 111.

So, for whatever reason, I have a mental block that prevents me from swinging a driver inside the way I swing outside. This issue seems limited to driver only, though, as my iron speeds were totally fine. If I were to go for a driver fitting inside and I didn’t know my normal numbers, I would likely be fit into a club/shaft combo that wouldn’t be optimal and I would be frustrated.

It is very possible that this is an issue that is limited to me, but I wanted to share this experience with everyone out there that may be considering getting a driver fitting at an indoor studio. Also, to the extent anyone knows, does TM4 have an issue reading driver CHS inside? I’ve never heard of this being an issue with TM4, but that could explain what I experienced yesterday.

I cant hit indoors. Dont know what it is, but my brain/body turns off and I cant do anything worth a damn.

I have the same issue. My driver swing inside is about 5-7 mph less than when we take the trackman outside. I am not sure why. Iron swings are about the same indoor or outdoor.

Glad to see it isn't just me. It is such a weird experience because I don't feel as if I'm swinging any differently, and my iron swings are the same speed indoors and out. Just the driver.

Did you happen to pay attention to the ball speed indoor vs outdoor?

I know Trackman reads CHS differently than most other launch monitors and sims (for example GCQ always reads higher CHS and lower smash factor) but it is interesting that the same Trackman measured the same club differently indoor vs outdoor. If your ball speed stayed the same then I wouldn't worry about it (misread CHS) but if the ball speed is also jumping 10-15mph then you really do have an issue with how you swing indoors.

Smash factor was similar, albeit slightly lower inside, so I don't think there were any misreads.

My work has three very short par 3 holes (100-180 yards). When I try to hit across the holes with a longer club which could go beyond those short holes, I just can't swing. My subconscious restricts my body and i can't help it. I know I am not talking about indoor but I think you are right. That's why mentality is the critical element of this game.

If you can’t acquire a target your body doesn’t know where to swing hard toward

For me, it’s usually the claustrophobia of a hitting bay. Even if I have space I feel like my swing instinctively tightens up and shortens in a bay versus outside.

I hear this a lot. I can't say I have any difficulties swinging indoor vs. outdoor, myself. @mgoblue06 is correct, if the BS is reading equally indoor vs. outdoor your friend might have not set it correctly. The system is based on a license and if he accidentally activated/bought the wrong one it MAY skew the readings. I don't use TM so I could be wrong but I know there are specific licenses for both indoor vs. outdoor, and that may mess up the point at which the radar is able to pick up the head movement.

I can’t swing in a simulator either. Probably something about KO’ing myself with a golf ball once upon a time.

Agree totally. It's like taking practice swings in your living room. Always very conscious of where every wall/ceiling is and everything gets compressed, loose extension, hang back, speed goes down. I've noticed the same thing if I ever hit on multilevel driving ranges. Afraid I will fall off the platform I guess. Of course this is all then juxtaposed by having the speed numbers right in your face, which causes you to instinctively swing harder than you would normally, throws off timing, and all goes too hell.

Won't see me at any indoor fittings.

I always feel like I'm going to let go of the club and throw it down the range when hitting from a 2nd tier. Doesn't make any sense but just can't put a decent swing on it.

Again, very curious about the exact ball speed readings. Ball speed will always be accurate with Trackman but CHS and smash factor can vary depending on environment and interference. Was the ball speed faster outdoors or not?

I honestly don’t know, as I didn’t look at ball speed numbers after noticing the huge discrepancy in CHS. However, I do remember smash factor being around 1.44 inside and 1.47 outside. Assuming TM uses nothing other than the CHS and BS values to calculate smash factor, I would guess that ball speed was down inside, as well. If ball speed stayed the same, my smash indoors would have been maxed out.

Smash factor just isn't an important stat. Assuming you were hitting the center of the face you would have exactly the same smash factor no matter how fast your swing is. The fact that the smash factor CHANGED actually means that CHS was misreading (most likely indoor but doesn't actually matter). Ball speed, spin, launch, and spin axis and carry distance are the only numbers that really matter with the driver. Ignore CHS and smash next time!

Throughout the year, I do see a few people who are not comfortable hitting indoors. I also see people hitting differently between indoors, the driving range and on the course when we do on-course fitting. That's why we always ask for feedbacks and do adjustments within 30 days of purchase.

However, I do believe that swing speed is not everything in fitting. Thus, worrying about a lower speed indoor vs outdoor will not present that much of problem as long as you are swinging the same. After all, it could also be the launch monitor and not you. The more you try to swing harder, the more likely you are going to swing it out of your shoes. When you do this, most of the time, the result will be off.

We used to put a big sign on the door: LEAVE YOUR EGO BY THE DOOR

This. This. This.

I never feel like I have enough room in a sim bay and I don't want to be that guy who smacks the wall.

I asked my buddy to see if he could look up the session. He said that the average driver numbers are:

Inside: CHS - 96, BS - 137

Outside: CHS - 111, BS - 164

The shots inside were tracked using INDOOR mode, while the shots outside were tracked using OUTDOOR mode.

Of note, my average driver CHS inside was 96, while my average 7-iron speed inside was 91. So, it seems my mental issue only applies to the driver. Although, to be fair, I only swung my 58, 7-iron, and driver inside, so it could be an issue (for me) with clubs longer than the 7-iron.

I am part of this club as well, lol. My issue seems to include anything longer than a 4 iron really. I can’t figure out what my issue is but it’s comforting reading others have similar problems with hitting indoors.

You aren't alone.

I can't release the club like I do outside. Not even close.

Driver SS indoors = 90 Outdoors= 95+

7 Iron indoors = 75 Outdoors =79-80

Are you sure this isn't just an issue Trackman's indoor mode? Hard to believe you are losing that much.

I've noticed my driver speed indoors with Trackman is 5-10mph slower than I get on GCQuad.

GCQuad always has higher swing speed numbers than Trackman (and lower smash factor) because of how it reads CHS. Trackman reads the center of mass of the club head while Quad measures the fastest part of the club head (toe as it's closing through release).

Ball speed should be identical with Trackman and GCQuad regardless of the CHS number.

Yeah I mean this definitely isn't a launch monitor issue. Quite amazing to have such a drop in speed being indoor. Was the room cramped with a short ceiling?

I can't say for sure that it isn't an issue with the Trackman, but the evidence suggests the Trackman is fine. Specifically, my 7-iron swing speed shows the same (91-93) whether I'm in or out.

As for the TM reading slower than GCQuad, that's a known difference between the two (GCQuad reads CHS higher than TM--this is also why you can get 1.50+ smash on TM and can't get above 1.46 on GCQuad). However, my understanding that the difference between the two is generally no more than 3mph, so your 5-10mph difference seems like it is caused by much more than the differences in how the units measure CHS.

Not really. The bay is in his barn, which is easily 2500sqft. The bay itself is at least 30 feet long and probably 20 feet wide. The actual ceiling was the roof of the barn, so it was a good 25 feet high. He did have a net over the bay to catch balls that were hit high, but it was at least 10 feet high. I didn't feel cramped, but it appears my brain was constrained by something.

Haha, doesn't seem to be any explanation for the difference. If you get a chance go hit indoor/outdoor again with his Trackman to get all of the numbers and see if you can't figure out how to swing indoors!