MK4

@DeadManI used to use the Swing Speed radar and, in hindsight, it seems very unreliable. As @iacassaid, it's prone to misplacement, and I'd sometimes get wildly different speeds from swing-to-swing: like a 103mph, followed by 118mph, then a 102mph, then a 114mph. I didn't know any better at the time and thought that was normal. I've since upgraded radars and the new speeds seem much more accurate/consistent. Also, Mike Carroll (FFG) used to have the SSR and he now calls it a 'random number generator'.

So, it's a two-part determination: (a) figure out the %; and then (b) adjust the putt to what a flat putt would be. I only do this for putts over ~20 feet. To do (a) and get the %, you can either use aimpoint or a green reading book. I use a book because I play the same course a lot, but after a couple rounds, you get a pretty good feel for what 2% is, what 3% is, etc. and don't need to use the book. If it's a long, undulating putt with varying %, then I average the %. To do (b), multiply putt length by the % times 11. Essentially, for a 3% slope, multiply the putt length by 33%, for a 4% slope, multiply by 44%, etc. And then, add/subtract depending on if it's uphill or downhill. So, a 30 footer that's downhill 2% is like a flat 23 footer. I figured out part (b) from a Geoff Mangum article, confirmed it with an old Dave Pelz book and from hearing Bryson discuss it, and then tested it on a couple different sims (GC4 and Exputt). This is all based on 11 stimp, and the numbers change slightly for other stimps (10, 12, 13). The change becomes more impactful for longer putts with bigger slopes and for bigger stimp disparities (going from 11 to 13). It seems like a lot, but it only takes a few seconds once you get the hang of it. The numbers don't have to be perfect (e.g., 2% vs 2.5%), but it gives a ballpark idea of equivalent flat putt length. The calculation becomes trickier on long putts (50+ feet), with a big slope (3% or more), through 3+ feet of fringe. For those putts, the math has to be more accurate because less margin for error. EDIT: for (b), you can also have a chart written down on a card or something, and then bring it on the course. I have a friend (bad at math) who does that.

I started using this method about two years ago for lag putts and it has been tremendously helpful for me. I have an Exputt, so that helps with practice at home, but any sim (or Puttist) would work - there are even some apps that can do it. Basically, on the course, (1) determine length of lag putt, (2) adjust for uphill/downhill %, (3) adjust for stimp (which is determined on practice green), and then you know the putter stroke length. I have poor eyesight, so lag putting was previously a weakness for me, but now is a strength. Admittedly, this method is pretty weird and isn't for everyone. FWIW, I only calibrate up to 50 feet, but I should lengthen that since I use this method for Texas wedge/fringe putts, which are often 50+ feet after adjustment/calibration.

What you've said makes sense to me. Though, when you say that putting is where you lose the most shots - are you tracking your SG and, as a result, it shows that putting is your weakness over time? Also, wouldn't your putting SG, to some extent, be unrelated to the tees that you play? Though, I suppose if you play shorter tees, you might have more GIRs, leaving you more lag putts.

Another thing that I thought of this morning: the chart that you posted is the average differential for all 10 handicap golfers. I wonder if the average diffs would vary for different types of 10 HCs - e.g., would a 10 HC whose strength is driver/approach fare differently than a 10 HC whose strength is short game/putting? I honestly have no idea, but it's an interesting idea. The reason I thought of this is because of the situation I described above (e.g., Florida course with forced layups from 6200 yd tees due to hazards). I think a person whose strength is driving distance would be more hurt by forward tees that necessitate a layup. I've spent far too much time thinking about this post, but it is really cool to see the numbers.

Very fascinating and makes complete sense. Makes me wonder: if a person wants to ‘game’ their handicap before a tournament, could they play tees that are sub-optimal for their distance to produce higher diffs (e.g., moving to forward/easier tees that require forced lay-ups, for example)? Conversely, if a person wants to lower their handicap, the data above indicates that they may want to play longer/harder courses (assuming no hazard issues like above, such as, for example, forced carries from back tees that are impossible for a person’s length).

This is interesting data and possibly related to a scenario for a specific course in Florida that I play. When I play the 6200 yd tees there (70 CR), I end up having to lay up with a hybrid or 4i on most of the par 4/5 holes (due to water or sand). However, from the 6800 yd tees (73 CR), I can hit driver on almost all of the par 4/5 holes. So, the approach shots end up being similar regardless of 6200 vs. 6800, but I'm sacrificing ~40 yards of distance off the tee (though, with slightly better dispersion with 4i/hybrid). My diff tends to be 2-3 strokes higher from the 6200 yd tees vs the 6800 yd tees.