Driver cg - low/high - affect on draw or fade bias

I've found the end of Google on this topic and don't see much specifically so I'm asking the club experts here...

All I found was an article that stated a more rearward cg can/does increase face closure rate.

Does low/high cg affect draw or fade bias in any way? Only talking rear/forward as heel/toe is straightforward.

> @getitdaily said:

> I've found the end of Google on this topic and don't see much specifically so I'm asking the club experts here...

>

> All I found was an article that stated a more rearward cg can/does increase face closure rate.

>

> Does low/high cg affect draw or fade bias in any way? Only talking rear/forward as heel/toe is straightforward.

Draw or fade bias is about Horizontal gear effects.

If COG is dead center, and we make impact dead center (heel to toe) we dont have any Horizontal gear effects in play.

If we make impact outside COG (more against the heel or toe side), the Horizontal gear effects comes to play.

Gear effect vary on strength depending on the distance from the impact and BACK to RCOG, so its not VCOG or vertical center of gravity that matters, but RCOG.

Now...depending on head design, and where we add weight to a club head, we might adjust both VCOG and RCOG slightly. Lets say we wanted LOW spin, so we add 10 grams just behind the face at the sole (lead tape outside or hotmelt inside). 10 grams dont move COG a lot (less than 1/8") but we also makes a slight influence on RCOG this way, making it shorter and closer to the face = stronger gear effect (lower MOI and less directional forgiveness)

The other way, we want added Dynamic loft, and adds 10 grams in the butt of the club head.

Depending on head design, VCOG might vary, but not much, while RCOG is stretched = Higher MOI, improved directional forgiveness, less Horizontal gear effect from less head twisting on shots outside the center.

So its not a high or low COG (VCOG) that matters, but Rearward COG (RCOG), so if VCOG is LOW, and RCOG short, you get a head like TM SLDR who is nice when you pure it, but a nightmare on impact outside the center of the face.

@"Howard Jones" is right as usual. High/low CG carries no bias towards a draw or a fade. When it comes to CG location, X-axis (left/right) governs draw/fade bias, Y-axis (high/low) governs spin via vertical gear effect bias, and Z-axis (front/rear) governs how strong those gear effects are. The Z-axis can also influence face closure depending on how aggressive your release is with more rearward weight influencing more face closure and vice versa for more forward weight. Tiger Woods alluded to this in that 2015 clinic video when he was testing backup drivers. He said that one of them had the CG too far forward and that he couldn't turn it over, implying that the face closure was different as a result.

A Long vs Short RCOG has effect on face closing, because RCOG will try to line up in "a strait line" down from your hands (like we swing a sling shot - the weight align strait down or out)

So, if RCOG becomes shorter, the player must add more face closing by his wrist to get the same face angle at impact

Thanks guys...exactly what I was looking for.

This came up because I tested 2 drivers head to head...m4 at 8.5 and m6 at 9.0. I have found that in the M2 and M4 drivers I have to play them in the upright lie position. I play a fade and those drivers had a fade bias for me so the upright lie straightened things out. Fast forward to Saturday on the range and I'm testing the M6 in upright setting. Basically no shots missed right...a lot of dead straight shots...BUT, several hard pulls. I went back and forth through about 100 balls and the m4 never missed left...would switch to M6 and the 2nd or 3rd ball would always miss left. Even tried a delofted position with that upright lie and still got pulls. Swingweight was the same. Exact same shaft.

Ran out of balls before I could do a volume test on the lower lie setting. A few balls hit in standard lie appeared to help. Will spend more time saturday.

> @"Howard Jones" said:

> A Long vs Short RCOG has effect on face closing, because RCOG will try to line up in "a strait line" down from your hands (like we swing a sling shot - the weight align strait down or out)

>

> So, if RCOG becomes shorter, the player must add more face closing by his wrist to get the same face angle at impact

>

>

That diagram poses a question...wouldn't a stiffer (or stiffer tip) shaft help reduce face closure rate in a more rearward cog?

Not only the shaft stiffness but also the swing mechanics (particularly how much loading and the timing of the shaft unloading). There are more 'forces' at play than just the centrifugal.

And it's really effecting how the face closes into impact and the face orientation at impact, which is not the same as saying it effects the face closure rate specifically. I would think the MOI about the shaft axis would be more influential to the closer rate. And even then probably only if the player's mechanics has a higher face closure rate as part of their swing.

Also, it's important to keep in mind that the amount of variance in Rearward COG among all drivers over the last few years is only about 1.5 cm (a bit more than 1/2"). So we are not really talking about differences that typically will not be all that significant.

Did more testing with the m6 in standard lie position...much better. Lefts were much less and much less severe. More controlled than the m4. Interesting that the slight change in cg can have such a difference in performance. My miss with the m4 is right...even in the upright lie position I play. Definitely have a harder time squaring the m4 face. Exact opposite with the m6...face squares up much easier.

> @getitdaily said:

> Did more testing with the m6 in standard lie position...much better. Lefts were much less and much less severe. More controlled than the m4. Interesting that the slight change in cg can have such a difference in performance. My miss with the m4 is right...even in the upright lie position I play. Definitely have a harder time squaring the m4 face. Exact opposite with the m6...face squares up much easier.

For LIE angle, you can use the ball marker test, just like for irons.

Use a whiteboard/dry erase marker and a strait line in the ball you place vertical against the face at address. Then you get to see if Lie angle is neutral, upright or against flat at impact

> @"Howard Jones" said:

> > @getitdaily said:

> > Did more testing with the m6 in standard lie position...much better. Lefts were much less and much less severe. More controlled than the m4. Interesting that the slight change in cg can have such a difference in performance. My miss with the m4 is right...even in the upright lie position I play. Definitely have a harder time squaring the m4 face. Exact opposite with the m6...face squares up much easier.

>

> For LIE angle, you can use the ball marker test, just like for irons.

> Use a whiteboard/dry erase marker and a strait line in the ball you place vertical against the face at address. Then you get to see if Lie angle is neutral, upright or against flat at impact

Thanks Howard. I know that test. Just figure for drivers, especially comparison of one M model to another, it's easy enough to just stand on the range and pound balls with both and observe flight...after all, they can only be adjusted upright or standard...I don't like changing face angle...