Launch Monitor calculated ballflight vs different ball aerodynamics -- does it matter?

[betarhoalphadelta]

So in threads I've seen discussions that launch monitors--particularly the personal ones--don't have the capability to determine ballflight on the entire distance of a shot, and certainly not when struck into a net. 

 

As such, they must be basing their predictions of ballflight for a certain launch angle, speed, and spin based upon a model of the aerodynamics of a golf ball. As is oft said about models, "All models are wrong; some of them are useful." Different balls with different construction, dimple patterns, etc will be different in the air. When is their model useful and when does it break from reality? 

 

While it would be ideal to tell an LM that I'm using a Snell MTB-X and it just substitutes that aerodynamic model, based on extensive testing, to give me what *my* ballflight should be... That's just not reality. So it means that unless the ball I'm using perfectly conforms to their model, that the model is giving me a different answer than what I would actually see in the world. 

 

So... Some questions:

 

1. Does it matter? Which is another way to ask whether the differences are statistically significant enough that if I'm using a premium ball that falls into the "middle of the road" category via MGS ball test, that my on-course results will deviate enough from the model that I can't trust the numbers? If I hit my 7i with 170 carry in the real world with that ball on a good strike, and the LM spits out anything between say 167 and 173 on average on good strikes, well, my variance is MUCH wider than that and I'm close enough. But if instead it could be giving me a number of 160 or 180, then I wouldn't be able to trust the numbers. 
2. If it matters, is there any way to know what ball the LM aerodynamic models are actually based on? Is it based on a specific ball (likely ProV1 due to popularity) or is it based upon a representative average of popular balls? 
3. If the answer to #1 is "yes" and the answer to #2 is something "Titleist ProV1" or "ProV1x", does this justify switching to the ball that the model is based upon in order to force your on-course performance to match the numbers you're getting from practicing with the LM and a net? I mean, Snell in volume is a little over $2.50/ball and Titleist is about $4/ball, so even on a day when I lose several I'm only out a couple extra bucks. My worst round in recent memory when I lost $6 balls only would have increased my marginal cost on that round by $9. On an average round I'm maybe out a couple extra bucks. Everyone complains about losing a $4 golf ball, but it's really only $1.50 worse than losing a DTC ball. 

 

Am I overthinking this? Given that I'm about to start using the R10 and a net for practice, I'm wondering whether I should just invest in some Flightscope dots for my MTB-X or if this is a time at which I should look at using the RCT for practice and then play the equivalent Titleist model on-course... 

[Bubbtubbs]

As long as the balls have similar spin profiles and compression ratings I don't think it's that crucial.

 

I play with Pro V1x or Z-Star XVs but use Ksigs most of the time on the launch monitor for working on drills or speed. The difference in spin is minimal and the average carry distance is within 2-4y. A mishit from any of my irons robs me more than that.

[betarhoalphadelta]

17 minutes ago, Bubbtubbs said:

As long as the balls have similar spin profiles and compression ratings I don't think it's that crucial.

 

I play with Pro V1x or Z-Star XVs but use Ksigs most of the time on the launch monitor for working on drills or speed. The difference in spin is minimal and the average carry distance is within 2-4y. A mishit from any of my irons robs me more than that.

 

My question is, "similar to what?" So the MGS test suggests that the numbers for mid swing speed (me) of the Snell MTB-X is pretty darn close to the ProV1. Compression is different, but ball speed, launch, spin, peak height, descent, and carry are all almost identical. 

 

Which is great, if the R10 is basing their ball model on the ProV1. In that case I'm close enough for government work. But is it? Does anyone know? Would a launch monitor vendor EVER dare reveal what their model is based on? If it's based on the ProV1x, carry is similar but all the other numbers aren't. 

 

I honestly see practicing with cheap balls as most likely for me. I've still got a bunch of brand new K-Sigs in a bag that I don't plan to play on course, and for the bulk of practice, I'm working on strike, directional control, and path. I could then only use the MTB-X on the LM every few months to make sure my carry distances haven't changed as I work on my swing. 

 

But if I'm using the LM to determine my actual carry distances, how close am I going to be to accurate if their model is different than the ball I play on course?  

[Dan13]

I had been thinking about starting a similar thread.  How big a difference can there be between balls if the speed, launch angle and spin are the same and it is only the trajectory "design" that varies?  Using My Golf Spy ball test data as reference the answer seems to be - not much - unless you are high speed player.

 

Based on very quick review:

For 8 iron with high ball speeds at 122mph (plus or minus a bit) with very similar spin and launch - you can see 3-4 yards of carry difference.  Not so much with mid swing speed (108mph). Max difference seems to be 1-2 yards.

 

Driver with high ball speeds (168-169mph) the max difference with very similar launch and spin seems to be around 5 yards.

 

So I don't think it is worth worrying about.  I do think the Flightscope Optimizer model trends a bit low but that is just my opinion and likely my hurt ego talking.

[North Butte]

On the other hand, the Ping ball fitting tool seems to keep suggestion Chrome Soft X and Tour B X for a large number of players because (or so it's been said) they both have "low lift/drag aerodynamics". Seems like if there's a big enough difference in aerodynamics to drive those two balls to the top of Ping's recommendation for so many people then maybe differences in aerodynamics do indeed exist. 

[Krt22]

19 minutes ago, North Butte said:

On the other hand, the Ping ball fitting tool seems to keep suggestion Chrome Soft X and Tour B X for a large number of players because (or so it's been said) they both have "low lift/drag aerodynamics". Seems like if there's a big enough difference in aerodynamics to drive those two balls to the top of Ping's recommendation for so many people then maybe differences in aerodynamics do indeed exist. 

Ping also has a distance chart where they go to +10 AOA of attack with driver, when almost know soul on earth can play functional golf in that regime.

 

For all but very high speed driver shots, IMHO aerodynamics are largely negligible to the average golfer in terms of impact on calculated LM distances vs actual ones. Ball type (cover and compression) will play a much larger factor.

[betarhoalphadelta]

2 hours ago, Dan13 said:

 

Based on very quick review:

For 8 iron with high ball speeds at 122mph (plus or minus a bit) with very similar spin and launch - you can see 3-4 yards of carry difference.  Not so much with mid swing speed (108mph). Max difference seems to be 1-2 yards.

 

Driver with high ball speeds (168-169mph) the max difference with very similar launch and spin seems to be around 5 yards.

 

So I don't think it is worth worrying about.  I do think the Flightscope Optimizer model trends a bit low but that is just my opinion and likely my hurt ego talking.

 

Thanks. That makes sense. Especially since I'm pretty squarely in the mid speed area and a 19 cap, so a couple yards here and there is MUCH tighter than my distance variance anyway. 

 

1 hour ago, Krt22 said:

 

For all but very high speed driver shots, IMHO aerodynamics are largely negligible to the average golfer in terms of impact on calculated LM distances vs actual ones. Ball type (cover and compression) will play a much larger factor.

 

Yeah, and I'll assume that for a middle of the road ball (I chose MTB-X because it was middle of the road but a little firmer and higher spin than the MTB Black) per the MGS tests the variance for iron shots isn't so massive that I need to worry about it. Even K-Sig which shows up as 4 yards carry shorter than the MTB-X is probably accounted for in the LM calculation that with the higher spin, it would be shorter.

 

Would be interesting to see a correlation between mainstream personal LM calculated results and the MGS testing with (I assume longer-range) radar, but obviously I doubt we'll ever see that. 

[Jeff58]

Frankly, if testing clubs without full flight observation, use a 2019 V1. Then there will be typically no (or at least very little) deviation from the model. 

 Nerdy statistical statement-

 

The other issue with using alternative balls is that not only does the model not fit to an unknown degree, the effects of the individual’s impact characteristics with the alternative ball vs the V1 is unknown. Solving for 2 unknowns in a fitting environment isn’t realistic.

 

[hammersia]

Unless the wind direction and strength, temperature, elevation and humidity are identical when you practice compared to when you play, which they will NEVER be, then no, none of the ABSOLUTE numbers matter that much.  

 

At the very highest PGA tour level, players sometimes undertake some normalisation work before a round to determine their distances that day, but that's always on a range with full ball flight. If they do this, I believe they use Trackman rather than Quad precisely to capture the full flight which is what is relevant, the Quad wouldn't allow them to dial in according to conditions.

 

What matters, why LMs are useful for many of us, is in determining relative numbers when we are either working on a swing change or trying different equipment.  

Edited December 8, 2022 by hammersia

[Bob Ferguson]

Don't want to be a "Debbie Downer" but here's a funny one. I was hitting inside using all my usual crap balls on the r10.I think worrying about ball selection does not apply to this unit. So as I was hitting, I had some hollow plastic practice balls i use outside mixed in with standard balls. Just for giggles i hit the hollow balls. (7 iron) The results were exactly the same as the other balls. If you looked at my range session stats you couldn't have figured out which was which! Strange.

[LongNwrong27]

Ability to accurately measure the ball parameters, ie launch, speed and spin far far more and is a far bigger potential source of error than minute differences in how different golf balls fly.