Trackman indoor spin rate accuracy

[frustratedgolfer]

Hi, new joiner so please be gentle!...

I have been on a Trackman outdoors and indoors and a Gc2 indoors too. Generally numbes seem similar on each.

However, with driver the spin rates vary fairly signficantly - on Gc2 driver backspin has been around 2,000 rpm, however on TM (both indoor and outdoor) back spin is 3,000-3,500 rpm.

I am going for a custom driver fitting on an indoor TM, but am worried that if the backspin on TM indoors is not accurate then we could be bringing the backspin down for the fitting but in reality take it too low.

It could also be coincidence, but on TM indoors it seems gar easier to hit a draw, compared to the TM outdoors or the Gc2 - is axis spin different?

How accurate are the spin numbers on each and should I be concerned about a fitting on TM indoors?

Thanks

[StuartG]

Keep in mind, these comments are for radar in general - not really TM specific.

indoors IF you have the recommended amount of room indoors (enough ball flight distance - usually ~10' tee to screen) AND are using the stickers on the ball AND there are no environmental source of interference (e.g. florescent lights seem to be the biggest potential problem), then you should be getting fairly accurate total spin numbers. Outdoors (if you have an 'outdoor' licensed TM), spin is calculated from the actual ball flight so should be very accurate - although realize that the ball type can make a big difference e.g. premium vs range ball. Not using the stickers on the balls tends to be the most common source of poor spin numbers for radar units indoors. Sometimes it works well despite not using the stickers, but not always as reliable.

I have no idea what will happen if you try to use an "Indoor" only TM license outdoors. I would hope it would just use the indoor mode - so all issues would be the same as if it was being used indoors - but can't say for sure.

Spin axis, however, is a separate topic. Outdoors, it's measured from ball flight so should be very accurate. Indoors however, (for now) it's actually calculated from the club data - path, face-to-path, lie angle, etc... If you hit the center of the face of the driver - it should be fairly reliable. If you don't hit the center of the face, gear effect can make it much harder to get accurate calculations - and that's only possible if the radar can detect the impact position on the face.

[LEO MODE]

I own both devices. Please refer to below report:

https://golfsimulatorforum.com/forum...gc2-hmt-gcquad

and spin is measured outdoor by counting the revolutions with the radar frequency sent out. It is not calculated. And currently with Trackman, you are correct that spin axis goes all over the place and doesn’t matter if it was struck on the center of the face or not. There is a huge update coming April to fix indoor gear effect issue on Trackman though so we can see how that will turn out. With the recent February OERT tracking update pickup rates have improved dramatically though which also increased the impact location accuracy a bit.

For now, my recommendation is to avoid fitting with Trackman indoor, especially for a driver. For irons, I would recommend focusing more on ball speed, launch angle, spin (with the dots on the ball and measuring and not calculating with italic numbers) and carry distance. As I said, ball flight indoor is not accurate until hopefully April update remedies it substantially. (although GC2/GCQ are much more preferrable for fitting indoor than Trackman, they also have problems such as carry algorithm issue and not 100% accurate spin axis either).

[mthunt]

I'd say the GC2 is right. TM needs a couple of revolutions and if you ball to screen is under 15 feet the readings won't be as accurate. Having said that using TM4 at 15 has been spot on for me

[frustratedgolfer]

Thanks for all your replies. That’s a little worrying to be honest as I’m worried the driver fitting won’t be accurate! I may discuss this with the fitter.

I’ve already done an iron fitting and found the spin rates with a 7-iron to be broadly similar on all devices (the fitters advice that my ball flight was too low with low spin made sense as I get good distance but struggle to stop mid irons on the greens). We’ve changed the shafts and weakened the lofts a tad.

Driver could be a different story and taking what appears to be a high spin (but is actually just right) down further could result in too low spin...

[StuartG]

TM needs a couple of revolutions

What gave you that idea? But I have to disagree. A doppler radar only needs one pass of the sticker to get circumferential velocity of the ball - which is what is used to calculate spin.

[mthunt]

My bad. One then. If you have 170 balls speed, 2000 Back Spin and 9 feet to the net you aren't getting one pass of the sticker which is what I was referring to.

[StuartG]

Just did the math and I got a little different results: for 180 ball speed (120 club speed), 2000 rpm, and 10' of distance tee to screen gives about 1.25 revolutions of the golf ball. That gives at least 2 potential opportunities to get the circumferential velocity. One when the sticker is oriented directly up, and one when it's pointed down.

Now, I fully admit, that's just the theory, I don't know if TM (or Flightscope for that matter) will use both or not but I would hope so.

[frustratedgolfer]

I don’t remember seeing dots on the balls when I went for the iron fitting - I’m guessing without the dots it’s even less accurate? From memory the distance from TM to screen was around 16-18 feet, and from tee to screen was probably around 10-12 feet...

[LEO MODE]

I realized that due to space constraints most of the facilities that used Trackman indoor only had about 10-11ft of space between ball and screen. I think that's still too short because with that space 7 iron shots would be calculated majority of the time. I have a 13ft distance I almost never get italics on irons and fairway/hybrids with the dots. I get italics on driver shots of about 2-3 out of 10 times.

[Dax]

The metallic dots on the ball would be a must on in my opinion, especially if you are doing a fitting.

[LEO MODE]

For Trackman they require 2 revolutions minimum to measure ball spin and while without dots could still be ok if you are getting a lot of italic numbers on spin even with a 7 iron (the farther the screen the more likely lower ball speed would measure spin) you would need to put the dot on the ball to ensure you get a proper reading.

[FaultyClubs]

Trackman has a chart showing the minimum required distance. It is a factor of ball speed and spin rate.

An example, for 150 mph ball speed you can measure spin rates above 1300 rpm at 15 ft, 1650 rpm at 12 ft, and 1950 rpm at 10 ft. So if one was happy only measuring down to ~2000 rpm then 10 feet would be OK etc.

Radar returns aren't simply "good" or "bad". They are a statistical value based on signal to noise and resolution so accuracy and reliability degrades until the result becomes worthless. It's too complicated for a user to determine so we rely on trackman guidance. Plus independent reviews against quads or real life to keep them honest.

[StuartG]

For Trackman they require 2 revolutions minimum to measure ball spin

Sorry don't take this the wrong way but by any chance do you have some reference from Trackman to validate that statement? I'm not saying I know different - but based on the math that doesn't seem likely in light of many of their claims for indoor sim use. It would mean that indoors, the maximum supported ball speed for a driver would only be ~125 mph - or a max swing speed of roughly 84 mph.

[LEO MODE]

It was confirmed by Trackman HQ when I was talking to them. You can also contact support@trackman.dk as they're always nice to answer any questions you may have. I agree that sometimes the math wouldn't agree in real life because I found that the ball speed/spin reading for certain distance posted by Trackman didn't always work as they said (i.e. a lot of times 15ft would still calculate ball spins more than 1300rpm) when I was testing it myself indoor.

[StuartG]

Interesting. I did send a question through their web-site.

But it would have to do better than that considering they are advertising a minimum room depth of 19' for a sim - and in general indoor setup only 16' radar to net. Sure that confirmation was for TM4 (and not one of the earlier models)?

[Dax]

LEO MODE i can’t find tour post on the topic, but recall you speaking to an upcoming update from TM regarding them working with golf ball manufacturers in order to help in terms having a ball that will allow for spin axis to be directly measured. I am now hopeful that this is just around the corner as I believe a patent expires today (someone else might need to confirm this as so know nothing of this area of law) regarding a golf ball that could be used to measure spin and spin axis. Might be a long shot and maybe I am reaching for straws, but who knows?

U.S. Pat. No. 6,244,971

[Stetson]

How can 15 feet from impact to screen possibly be functional? The screen would have to be 22’ tall to hit wedges lol

[Dax]

How can 15 feet from impact to screen possibly be functional? The screen would have to be 22’ tall to hit wedges lol

Protect the ceiling. I hit mine all the time from 10 to 12 feet (even with a pitching wedge) and just have archer netting taking the blow. At 15 feet you just need to have the ceiling protection in the right places, but this is very doable. Ball hits either a net or ceiling protection and bounces to screen. No issues at all... My version 3.0 build will be doing something else for ceiling protection potentially (not fully thought out yet).

[Stetson]

Protect the ceiling. I hit mine all the time from 10 to 12 feet (even with a pitching wedge) and just have archer netting taking the blow. At 15 feet you just need to have the ceiling protection in the right places, but this is very doable. Ball hits either a net or ceiling protection and bounces to screen. No issues at all... My version 3.0 build will be doing something else for ceiling protection potentially (not fully thought out yet).

But certainly not hitting the screen correct? You had me thinking I was crazy haha

[Dax]

Only after it hits the netting that I have protecting my ceiling.