Sim v Sim max spin

On avg how much more does the sim max spin compared to the sim?

No one has hit both on the monitor with same shaft?

I hit them both with the same shaft. The SIM definitely spins less than SIM MAX, sometime spins too less for me, say only 1500. The spin of SIM MAX is much healthier, say 2000-2300 for me, even by hitting a cut, the spin from SIM MAX is only about 2500-2800 which is pretty good compared to my M6 (3000-3600).

TXG did a comparison you can find on YouTube. I watched it last week but I believe the spin variance was roughly 400rpm (somewhere between 300 and 500)

I get ~2700 for sim max and I got 22-2300 for Sim. But I went with Max for the better dispersion.

We have to compare spin rates "all else equal" and we can hardly ever get that without a Robot, but 3-500 sound about right, but since Vertical gear effects is the ruler of spin, and we can use the formula 1/8" up or down on the face = 240 rpms of spin, the highest spinning head will have the same spin level as the other if we move impact only 2/8" higher on the face. That means its limited what the head can do, and also the effect of it, so go by the one with best dispersion in your hands.

500 rpms is 5-7 yards more roll out when fairways allows that but about the same carry...it might vary some depending on ball speed and launch angle.

While working through Howard Jones’s driving fitting pdf I balanced the SIM Max on the tip of a pen and was very surprised that the vertical axis is towards the heel, not in the center. This was without an adapter, with the adapter it is even further towards the heel. A ball struck halfway between the toe and heel will make impact toe side of the vertical axis, creating higher ball speeds as HJ has referenced.

Thats a small misunderstanding, for the absolute max ball speed, we dont want to make impact to far off VCOG, and when we get COG directly behind the ball we are "optimized", but since the toe side travels a bid faster that center and way faster than heel side, we can take advantage of that, and get a few mph extra ball speed.

Thats the simplified explanation, but to really understand this,. the heads BIAS and our face angle vs path come to play, so to make a long story short, the absolute max is what we can get when we hit a draw, but with a FADE Bias head....COG moves to the toe side when we close face angle vs path, and thats beneficial since like mentioned above, ideal is to have COG directly behind the ball, so combined with a impact thats 10-15 mm toe side we get that. Here is how it works.

If we have a neutral COG (dead center of the face), and our face angle is square to path, and impact dead center, we have COG directly behind the ball. For a FADE we use a out to in path, and face angle thats open, now COG moves heel side, so ideal impact is a tad heel side.For a draw we use a in to out path, and a face angle thats slightly closed to path, now COG moves toe side.

Its simply the direction COG travels at impact we are talking about. This movement is not large, and the longer RCOG is the more it moves both ways, so when we want to take advantage of the higher club speed on the toe side, we want COG to follow, and even better, if its slightly toe side before we close up face angle, so a Draw made using a FADE biased head is ideal, while a toe side impact on a DRAW biased head has the potential to create horizontal gear effects we loose control over.

This illustration is NOT that good, the club speed lines goes 90* from the shaft, so they are to steep here, they should have been more flat. Ideal is to make impact between the 100 mph and the 102 mph club speed line, so we can get 2 extra mph club speed this way, and boost smash factor above 1.50 (up to 1.53)

When we take both movement of COG and this club speed lines into consideration, we ends up with a ideal impact for Draw thats higher on the face than for a Fade, because if we had them at the same height, we would loose to much club speed on that spot, so we lower impact to get on that 100 mph line as the best we can do, even if we are a tad heel side, and illustrated, it then looks like this, where the yellow marked area is the area we should try to make impact depending on fade or draw.

Feel free to ask any question about this, its not easy to wrap the head around this if you never seen it before.

That is a very thorough and clear explanation. I never thought of it or heard it explained that way.

If the club path is 0* at impact the COG is pointed directly down the target line.If the club path is from the inside the COG's path is now to the right of the target line (reversed for path's from the outside)If the COG's path is now to the right of the target line than COG is now in line with a point further towards the toe of the clubThe key is to disassociate the COG's location with the spot on the face at a 0* path, because the path of the club (and COG) will change the location at impact supported by the COG.I may just have to grab a sharpie and put a green and red dot on the face of my driver moving forward to have a visual reminder lol

Thanks HJ

Seems like you got it right, not everyone manage that even with a explanation, but let me make it clear that the movement of COG is not large, we can visualize it if we know where RCOG is seen from above, and use a protractor with the same radius as the distance from the face to RCOG, and then open or close the face, lets say 2-3 vs path, then we get to see that COG moves like i explain here, so if we really want to maximize it and draw is the preferred ball flight, we should use a fade BIAS head to get COG as long out against the toe as possible in the attempt to get COG directly behind the ball when we try to take advantage of the higher club speed toe side.

Great, thank you HJ.

silly me, forgot the most important....you measured your club head and found COG heel side = draw bias, but when you hit a draw with that club, you close face angle, and COG move against the center, and opposite for a fade bias head, the COG starts toe side in address position (sqaure), but the open face angle at impact has moved COG against the center.

So if one were wanting to hit a draw and wanting a fade biased driver, it would appear the COG of this particular head would leave a little on the table?

I know we are talking a few mph of ball speed, not 10+ yards.

Thats a question of where COG is vs impact and thats what i wrote about above...The longest Draw is made using a FADE bias head and impact toeside so we have COG behind the ball, and at a spot where club speed is higher than the center of the face. Impact outside COG does loose some PTR but the largest problem is head twisting and horizontal gear effects (unwanted or too much fade or draw tilt on the spin axis)

In your opinion in order to achieve fade bias would the best way, without changing drivers) to lighten the rear weight on the SIM Max and add hot melt rear on the toe side of equal mass?

if someone has the regular SIM will sliding the weight towards the toe (not all the way) achieve this goal or does the change in mass need to be further from the face?

i dont know that head, never seen it, but if we want to keep a high MOI value on the head, and take advantage of how COG moves when we open or close the face, adding or moving weights should be done as far back on the head we can get. We can play around with lead tape and do new measurements like you did with the pen to follow how much and where we move COG. It will always be limited how much weight we have to move around, so dont expect to see large changes.

10-4 good buddy. I appreciate the time discussing the topic