Mevo vs Skytrack data (Also graph of where ball speed differences start to show up)

[Dave Lee]

I was going to post this in the high speed inaccuracy thread...but decided if somebody wanted to look up mevo vs skytrak data in the future, this would be easier to find. (The ballspeeds I got also don't qualify as high speed haha)

Anyways, I got a new Ipad so decided to renew my skytrak plan. Since I could start exporting shots again, I thought I would do this comparison. (note: flightscope has a terrible data export page...it only captured 13 out of 40 shots. I basically had to hand type in my mevo data)

To sum up the test, I hit 9 x 8 iron shots and a lot more driver shots. I tried a white and black tee color to see if that made a difference. I also hit a bunch of half swings to try to vary ball speed and contact. Which is why you see some weird driver ball speeds. I used total skytrak spin to compare against the mevo spin numbers. I didn't use metal dots for this test

WHAT I SAW:

- the delta between skytrak and mevo does scale with ballspeed. It was about 1 mph in the low 100 mph ball speeds. Once you start passing 140 mph, the delta starts approaching the 3-4 mph difference. Which is inline with the higher swing speed deltas people are seeing. It's pretty much a ballspeed issue. You can see on the graph the ballspeed delta is the same when i used an 8iron and driver

-tee color made no difference

-adjusting the skytrak up 2 inches made no difference. Moving the Mevo up changes the launch angle by 3 degrees. LA matched between the mevo and skytrak when i had the mevo on the ground..but then the mevo started missing driver swing speeds. It still measured ball data fine

-mevo swing speeds were around 5+ mph higher than skytrak estimates. I don't really believe the skytrak data but im pretty sure the mevo reads high too. This has been confirmed with my skypro

-Without metal dots, the mevo spin numbers are in the same ballpark as the skytrak total spin. But there were a lot of cases where they moved in the opposite direction from shot to shot. Basically, you can't get super accurate spin numbers with the mevo minus dots...but on avg they are in the right range...so distance estimates are prob ok on the avg

-flightscope carry estimates are a lot higher than skytrak ones. They prob use different algos...but wasn't expecting that big of a difference. In the 100 mph ballspeed range, the skytrak had about 5 less yards of carry. The difference blew up in the 140 mph ball speed range. Big chunk of that is the 4 mph ballspeed difference. But that wouldn't account for some of the 20 yard differences.

Anyways here are some graphs (Edit: added the Carry differences)

[trumb1mj]

Thanks for this awesome study! I'm looking forward to seeing what SkyTrak finds and how they conduct their study... I would love to see this study done with Trackman and GC2.

[SkyTrak_Seth]

Nice work. I haven't used the Mevo so I can't really comment on accuracy/differences. Our test will be done with a robot and Trackman. If we need to make changes, then I'll work on a way to make it retroactive for your history as well.

[Clevited]

I have seen a few comparisons on youtube. Here are some of the video comparisions I have found. It includes mevo vs skytrak, mevo vs flightscope, and mevo vs gc2.

Mevo vs Skytrak

https://www.youtube.com/watch?v=1xqDx70RBlg&t=532s

Mevo vs Flightscope

https://www.youtube.com/watch?v=qHAN96RvIaA

Mevo vs GC2

https://www.youtube.com/watch?v=bervuMHXv-A

https://www.youtube.com/watch?v=qG9s0jm8YNQ

https://www.youtube.com/watch?v=klEJ29cJN-g

Edit: Here is a trackman vs skytrak video, ball speed difference is 4 mph with a 7 iron.

https://www.youtube.com/watch?v=J2M3MXJj4JQ

Edit 2: Here is gc2 vs skytrak

https://www.youtube.com/watch?v=z5bifppIjq4

[trumb1mj]

Nice work. I haven't used the Mevo so I can't really comment on accuracy/differences. Our test will be done with a robot and Trackman. If we need to make changes, then I'll work on a way to make it retroactive for your history as well.

Wait, isn't ST supposed to be MEASURING ball speed? Are you saying there are adjustments being made to a calculation?

[SkyTrak_Seth]

Yes, SkyTrak measures ball speed. We are doing this test to see if the measurement is low for high ball speeds. If so, that will be addressed on the hardware side. However, most people still have a ton of historical shot data, the only way to get that past data to the new standard would be via applying a conversion factor.

[trumb1mj]

Got it. Thanks!

[Clevited]

Awesome Dave, thanks for doing that, you beat me to my Trackman comparison, no time no money lol.

I would like to add that from what I observed in the past and what others have observed and from my own understanding of Skytrak hardware (I read all the patents), it seems up to 5% low is common at actual ball speeds in the upper 170s and 180s. This jives if the problem is real and is caused by difficulty picking ball centroids at those speeds. With the cameras it has, motion blur I would think is possible and could be the root cause.

I am just making an educated guess here.

Edit: As I have mentioned elsewhere, 1-3 mph over or under is perfectly acceptable to me, its when we start approaching 6,7,8 mph under that I start to get bothered. It might be that after many shots this averages out to 5 or so, which to me is too much as well.

When you have a drive on sim that ST shows is 175 bs but is really 180 or more, thats quite the difference and can mean carrying a hazard or not carrying a hazard. Tightening up that deviation would be awesome and is on my wish list.

[Clevited]

SkyTrak_Seth

I just got done doing a 1 hour test vs Trackman 4.

I used brand new Nike RZN golf balls.

I was indoors, large simulator bay, hitting into a projection screen. Two LED room lights on, not directly over Skytrak much like my garage setup. Projector was mounted above and didn't shine on Skytrak at all. I only focused on ballspeed, but I was going to look at all parameters but I screwed that up. Skytrak showed only backspin and side spin, TM showed total spin so I had no idea how to compare that. I also forgot to export launch angle from my Trackman data. Didn't know until too late I needed to check that as a parameter to export. Oh well. Got ball speed.

One note. I didn't notice any trend with vertical launch angle and ball speed or horizontal angle and ball speed. Ball speed alone seemed to be the cause of accuracy issues.

Sub 100 mph ball speed (Trackman): ST was off by an average of +0.99 mph
110-120 mph (Trackman): +2.69
120-130 mph (Trackman): +2.28
130-140 mph (Trackman): +1.84
140-150 mph (Trackman): -4.85
150-160 mph (Trackman): -3.73
160-170 mph (Trackman): -3.38
170-180 mph (Trackman): -3.31

While the average doesn't seem too suspicious (I only hit about 30 drivers shots), the spread was concerning. I had a maximum difference of -7.8 mph (when hitting 5w oddly). I had a total of 5 shots in 30 swings that had ballspeed 1-3.1 mph above Trackman. This was for shots that were between 160 and 180 mph on Trackman.

Attached is a screen shot of ball speeds between 150-180 mph. Trackman ballspeed on the left, ST on the right, difference on the far right.

Edit: I corrected and added to the table above. I was missing 140-150 bs and had one number in the wrong row.

Edit2: Caught an error in the excel picture I posted. Showed a difference of 6.2 mph higher for one shot on Skytrak. That was a typo. The numbers should be flip flopped. Should be -6.2 mph for the ST.

[SkyTrak_Seth]

Awesome, thx! Robot testing in 2 days

[Clevited]

Woot woot!

[Dave Lee]

Interesting that your lower ball speeds were positively biased. My were still lower on the skytrak in that range. It’s possible that’s a Mevo vs trackman difference. Or maybe there is a launch angle influence

SkyTrak_Seth

I just got done doing a 1 hour test vs Trackman 4.

I used brand new Nike RZN golf balls.

I was indoors, large simulator bay, hitting into a projection screen. Two LED room lights on, not directly over Skytrak much like my garage setup. Projector was mounted above and didn't shine on Skytrak at all. I only focused on ballspeed, but I was going to look at all parameters but I screwed that up. Skytrak showed only backspin and side spin, TM showed total spin so I had no idea how to compare that. I also forgot to export launch angle from my Trackman data. Didn't know until too late I needed to check that as a parameter to export. Oh well. Got ball speed.

One note. I didn't notice any trend with vertical launch angle and ball speed or horizontal angle and ball speed. Ball speed alone seemed to be the cause of accuracy issues.

Sub 100 mph ball speed (Trackman): ST was off by an average of +0.99 mph
110-120 mph (Trackman): +2.69
120-130 mph (Trackman): +2.28
130-140 mph (Trackman): +1.84
140-150 mph (Trackman): -4.85
150-160 mph (Trackman): -3.73
160-170 mph (Trackman): -3.38
170-180 mph (Trackman): -3.31

While the average doesn't seem too suspicious (I only hit about 30 drivers shots), the spread was concerning. I had a maximum difference of -7.8 mph (when hitting 5w oddly). I had a total of 5 shots in 30 swings that had ballspeed 1-3.1 mph above Trackman. This was for shots that were between 160 and 180 mph on Trackman.

Attached is a screen shot of ball speeds between 150-180 mph. Trackman ballspeed on the left, ST on the right, difference on the far right.

Edit: I corrected and added to the table above. I was missing 140-150 bs and had one number in the wrong row.

Edit2: Caught an error in the excel picture I posted. Showed a difference of 6.2 mph higher for one shot on Skytrak. That was a typo. The numbers should be flip flopped. Should be -6.2 mph for the ST.

[Clevited]

Yes, I was very surprised by that as well. I did however hit some shots on those speed ranges with different clubs and they were still higher on ST.

[Clevited]

Dave Lee did you have any large deviations in ball speed during you test? I saw almost 8 mph low one time and a few other significantly large deviations. This has me more concerned than the running average you or I have recorded. A few mph max off here and there at worst is perfectly acceptable to me, but not 4 to 8. I dislike having back to back great driver swings when practicing with the range app, each with center contact but differing in ball speed by sometimes 5 or more mph. I have had 180 one strike and 175 on another strike knowing full well I struck it at least as well as the previous one. Frustrating.

[Clevited]

I made a couple of plots to help illustrate my test.

[trumb1mj]

I have had 180 one strike and 175 on another strike knowing full well I struck it at least as well as the previous one. Frustrating.

This is what really frustrates me. I'll smash 2 shots with the same exact swing speed reading from my SSR, check the face and both are out of the middle yet see 4-8 MPH difference in ball speed. It makes you wonder...

[Clevited]

Made one more graph showing the area I really care most about.

Edit: I did a little more number crunching. From 145-180 mph, Skytrak ball speed was 3-7 mph off from Trackman 80% of the time, it was less than 3 off from Trackman 20% of the time. Essentially 80% of the time for that range of ball speeds, Skytrak is what I would call unacceptable when compared to the "industry standard" Trackman.. It only gets it "right" 20% of the time. Of course this is compared to a machine which has its own accuracy range.

An additional note, 77.5 of that 80% number, the Skytrak was 3-7 mph LOWER than Trackman. The other 2.5 the Skytrak was high by 3+.

[Dave Lee]

The the third image shows the spread of differences. At my driver speeds (145-150) the bias was about 3 mph low with a +- 2 mph spread.

Although some one of that may be due to outdoor range effect. The memo measures the first 40 yards of flight. So it can still be impacted by environment.

Dave Lee did you have any large deviations in ball speed during you test? I saw almost 8 mph low one time and a few other significantly large deviations. This has me more concerned than the running average you or I have recorded. A few mph max off here and there at worst is perfectly acceptable to me, but not 4 to 8. I dislike having back to back great driver swings when practicing with the range app, each with center contact but differing in ball speed by sometimes 5 or more mph. I have had 180 one strike and 175 on another strike knowing full well I struck it at least as well as the previous one. Frustrating.

[Clevited]

My bad, I forgot about that graph. Looked to me like you had quite a few in that 3, 4, and 5 mph low area at your higher speeds. So you had a maximum of 5 or so low?

Looks rather consistent with what I saw near your speeds. The really out there numbers didn't start until the 150s. My ST might have started loosing its mind a little sooner than yours might, who knows.