Is launch-monitor spin accurate?
Not accurate enough to practise on. Not on a home unit, and not as much as you'd think even on a TrackMan. Spin is the number everyone wants to fix because it's right there on the screen. It's also the least reliable number your launch monitor gives you.
The study that settles it
The best test of home launch monitor spin put a FlightScope Mevo+ next to a TrackMan 4, with 29 young golfers hitting ten drivers and ten 6-irons each. The speeds matched. Spin didn't:
- On average the Mevo+ read up to 1,238 rpm away from TrackMan.
- On a single shot, it could be anywhere from 2,628 rpm too low to 5,103 rpm too high.
Now compare that with what you're trying to fix. The USGA and R&A measured the average male amateur's driver at 3,275 rpm and the PGA Tour average at 2,686 rpm. That's a gap of 589 rpm. The error is several times bigger than the whole gap between an average golfer and a tour player. If the screen says you've "lost 400 rpm", that could easily be nothing.
That was a Mevo+, not an MLM2PRO. Nobody has tested MLM2PRO spin, so there's nothing better to go on. The MLM2PRO only measures spin with its marked RPT ball. Without one, the spin on your screen isn't a real reading.
Even a TrackMan struggles with it
This surprises people. Another study had good golfers hit ten drivers in each of two sessions on a TrackMan 4. Club speed and ball speed barely moved between sessions. Spin moved by 241 to 455 rpm, and for some players one session's spin said almost nothing about the next.
That's on the best device there is, so it isn't the hardware. Your spin just moves a lot on its own, because it depends on things that change from swing to swing and bay to bay.
What moves spin that isn't your swing
Spin reacts to almost everything:
| What changed | What it does to spin |
|---|---|
| Hitting off a mat instead of grass (8-iron) | About 1,000 to 1,300 rpm less |
| Worn wedge grooves (new vs about 500 bunker shots, 50 yards) | 7,021 down to 3,737 rpm |
| Premium ball vs a cheap one | Roughly 12–15% different on some shots |
| Range balls, pitching wedge | About half the spin |
| Striking it low on the heel vs the centre (driver, robot) | 3,310 rpm vs 2,710 rpm |
The last row is the useful one. A swing robot got about 600 rpm more spin just by missing low on the heel. A lot of "too much spin" is really where you hit it on the face.
What to do instead
For most amateurs, too much spin is a strike problem, and strike shows up in a number the device measures well: smash factor. The same USGA and R&A data has the average male amateur swinging 93 mph, about the same as the LPGA average of 94, but getting 7 mph less ball speed and 664 rpm more spin. Same speed, worse contact.
So:
- Work on strike and watch smash factor. It's ball speed divided by club speed, both measured, and it changes with where you hit the face.
- If you look at spin, use the RPT ball and average it. Between two sessions of ten shots, spin has to move about 500 rpm before it's likely real, and that's a generous estimate.
- Don't chase one "perfect" spin number. The published charts give a range of 350 to 500 rpm even for one swing speed. Two players with the same speed can have different best numbers.
- Don't compare spin across balls or surfaces. Mat against grass, or range ball against your own ball, just shows you the difference in conditions.
Sources
- Brennan et al. (2024), Validity and reliability of the FlightScope Mevo+ launch monitor, Journal of Strength and Conditioning Research.
- Bliss and Langdown (2024), Trackman 4 within- and between-session reliability, Journal of Sports Sciences.
- USGA and R&A (2022), Equipment Specifications Research, June 2022 — the tour and amateur driver averages.
- MyGolfSpy, Worn wedge grooves spin testing — industry testing.
- Golf.com, Range ball vs premium ball robot test — industry testing.
- Golf Digest and Golf Laboratories, Robot mishit-location testing — industry testing.