OT: distance adjustment for altitude

[Matt_Cohn]

I have a tournament next week at about 6,000' feet (Schaffer's Mill in Truckee). I'm interested in the most detailed/scientific analysis available of the effects of altitude, and I figured someone on here might have that.


To be clear, I know the basics: more adjustment for shots that fly high; less effect from sidespin; shallower decent angles; etc. I'm looking for whether I should adjust my driver by 0.5° or 1.0°; whether I should play irons at 6% or 7%; that kind of thing. The best stuff I can get short of bringing a TrackMan out to the range. Thanks everyone!

[Jim Hoak]

Matt, there are probably people on here more qualified to be exact than I, but when I used to play on a course outside of Denver at about 6.000 feet, I always took off 10% on a shot.  So a 160 yard shot would be 144 yards.  I used 10% because it was very easy to calculate, but it seemed to be about right.  Maybe I was being lazy but how are you going to calculate 7%?

[Kevin_Reilly]

Matt is smart enough to calculate 7%! 


But more seriously, hopefully Matt you will get some time to practice up there.  In my experience, strict mathematical adjustments don't always apply at altitude, or rather, as you noted, there are other factors at play.  Get some practice round time!

[Matt_Cohn]

I’m going up an extra day early so I’ll have two practice rounds at that altitude. And now that we’re allowed to use our phones during tournament rounds—in fact, expected to use them for scoring—7.2% of 214 yards is just a few quick taps away!


The easy hack is just to set your rangefinder to meters. Pretty close to 10%! 

[Kalen Braley]

7% isn't bad, especially if 7.5% is close enough.

For example.  On a 180 yard shot, calculate 10% at 18, divide by 2 to get to 9. Then divide by 2 again to get 4.5 and add it back to 9 for a 13.5 yard adjustment.  Seems doable.

[Dan_Callahan]

I used to play a few times a year in the Aspen/Basalt area. Coming from Boston, the distance adjustments were hard to get used to. My best advice would be to find a very good local caddy, have him watch you on the range to get a feel for your yardages, and then hit whatever club he hands you without giving the distance a second thought. Because if you know you have 180 yards and he hands you a pitching wedge, you can't help but overswing. If you are blissfully ignorant, you just trust he knows what he's doing and can focus on hitting a good shot. I felt the same way about reading the greens. With courses that are routed through valleys, I often completely misread the break. So I learned to swallow my ego and trust my caddy.

[JESII]

Matt - not a ton of golf at elevation experience, but my recollection is that shots you hope to spin a little will have substantially less spin. Medium pitches (40-60 yards) or full out wedges to a front pin seem to be more difficult to control.

[MClutterbuck]

How dry or humid will it be? Lack of humidity can reduce the altitude gain...

[Wade Whitehead]

At almost 9,000 feet we added 10% to each club to predict how far it would go.

150 yard club went 165, etc.  This gives a slightly different result than adjusting down but they're close.

WW

[Matt_Cohn]

How dry or humid will it be? Lack of humidity can reduce the altitude gain...

Humidity has a extremely small effect on distance (though you're correct about the direction of the relationship). Does something about that change at higher elevations?

[Mike_Trenham]

As a low ball hitter, I’ve always felt that my gains were less than others at high altitude.  Is this correct?

[Tom Bacsanyi]

I'm at 8000 feet. When I go down to Denver, I lose about a half a club. When I go down to sea level I lose a full club.


Of course in the mountains everything is either uphill or downhill or into a wind or downwind. So best of luck to you.

[Matt_Cohn]

I found the resource I was looking for: https://flightscope.com/products/trajectory-optimizer/. Input launch speed, angle, spin, altitude, etc. and it gives you distance.


In my case I found that wildly changing my launch specs (from 13.5° and 2250 RPM to 15° and 2000 RPM) was still only 5 yards, and that's barely a realistic combination. Increasing my launch angle by a degree gave me like a yard. Not enough to switch heads for, or anything like that.


I'd seen from TrackMan's instructional video that distance gain peaks with the 6-8 irons and is less with longer irons (lower flight) and shorter clubs (less air resistance at slower speeds). Video here: https://youtu.be/KBrVOc21kiI. However, the FlightScope site indicated the greatest gains with the wedge through 8 iron (about +10% carry)—basically the clubs with the highest launch angles—even moreso than with the driver (about +7% carry). However, the driver nearly caught up when factoring in roll, as the flatter trajectory at altitude produced about 8 yards more roll than at sea level.


So...I'm glad I'll have a couple of practice rounds.

[Tommy Williamsen]

Matt, I hate to admit it but some of what you wrote is way over my head. The rest is way way over my head.

[Matt_Cohn]

Matt, I hate to admit it but some of what you wrote is way over my head. The rest is way way over my head.

Ball go far. Nobody know how far. 

[Tim Leahy]

Living in Sacto I have played Truckee and Tahoe alot and found that the shots to watch out for are the full wedges. The more you compress the ball the further it goes at altitude. I was flying greens with my wedges even with distance adjustments. So check those on the range in practice for more distance than expected. Stay hydrated. Good luck.

[Thomas Dai]

Would have made for an ‘interesting‘ discussion with Bryson if the tour still played at Castle Pines.
Atb