Why do Titleist tour pros use D2 driver?

I see a good amount of the Titleist guys (Walker, Spieth, etc.) are playing the 915 D2.  Sort of curious why they play this model and not the D3.  I've tested the D2 and it was significantly shorter for me: couldn't get the spin lower than 2700 rpm, average carry of 245-250, average total of 260-265.  D3 on the other hand is one of the longest I've hit, and extremely accurate: spin around 2000-2100 rpm, average carry of 260-265, average total of 275-285.  I'm sure my 105-108 swing speed is a lot lower than all the pros, so how is it the D2 fits them better than the D3?

Short answer? Because they are better. The D3 works better for you because of how forgiving it is allowing for better numbers even on strikes that aren't perfect. The Pros have near perfect strikes on almost all their shots therefore the D2 works better for them.

This is just why I think they use the D2 over the D3. I could be way off.

*disregard, apparently I had the numbers backwards in which was the forgiving and which wasn't*

Do I have it backwards? It's quite possible considering I have never looked at getting any Titleist drivers before. If so, whoops! My bad.

Yeah, the D2 is the higher spinning, more forgiving model.  D3 is a small head (440 cc vs. 460 cc for the D2), low spinning "more workable version".  Hence my curiosity as to why the pros play the more forgiving spinnier model.

That would make more sense.  The D2, just like the 815 Alpha was a high spin beast for me.  Sky high flight that just balloons and drops like a rock.  Can't say enough about the D3 though.  I play a 9.5 and still launch it plenty high, but it just...goes.  Sound was f*ing god awful at first until I stuffed it with cotton.  Now it sounds like a SLDR.

I've heard stories of a D4 for tour players... maybe it looks like the D2 and is low spin.

Thanks.

I guess Titleist players can no longer complain....

I don't think so; not with the 910s. Pretty sure he used the 910 D2.

To the OP (and don't take this personally). Could it be that these D2-using pros have optimum swing characteristics giving a slight +ve AoA at impact, therefore benefiting somewhat from the added spin characteristics of a D2 cf. a D3? In your case, could it be that you have a somewhat -ve AoA at impact and the added spin that gives to the D2 launch characteristics mean that, in your case, the D3 fits you better?

I think he used a D2 and D3, don't know which order, which series ... but I think as Titleist improved the low spin capability of the D2, he eventually played it.

Good question as to your principal point.

That's a good thought, but my AoA is (according to trackman) generally between +2 to a little over +3. From what I've heard the pros often have a somewhat negative AoA because they swing so fast they don't need the upward AoA to get the added distance, and for them the negative AoA is easier to control.

Yes,  some pros. -.5 - -1 is negative ... but not much.

And not all of them swing super-fast.

Sorry, my mistake and you are quite correct. Rory switched to the 913 D3 from the 910 D2 as he was struggling with the spin rates he was getting: http://www.golf.com/equipment/rory-mcilroy-switch-titleist-913-d3-driver-ended-his-slump

just spitballing here but maybe it has something to do with their miss with the driver.. Mark Crossfield explained something similar on his channel a couple months ago when he switched back to a slightly higher spinning driver.  He made the switch because when he missed , he missed in a spot that took too much spin off and the ball was just falling out of the air---could be something similar with the D2 players. Obviously they dont miss the center of the face very often but when they do they are still getting good numbers with the D2 and they are happier trading a little bit of max distance for that little bit of consistency.