Lead tape, is it illegal?

Its not something I've ever played around with but just a thought....

You have a 460cc driver and decide to stick a bit of lead tape on it. Bearing in mind you're already at the 460cc limit does the application of lead tape make it illegal?

As Ivan has said No, legallity part would ony arise if you removed the lead during a competitive round, thus altering the charicteristics of the club (forgive me if you new that Brian).

Wow Ivan! That takes some reading, and even harder understanding. I've always understood that mass times acceleration will give you the force applied to the ball. I hadn't appreciated the need, if possible, to have the COR tuned to a particular swing speed. However, maybe this explains, partly, why my 'gentle' tee shots can often fly further than one I've gone after.

I think that I need to put the same effort into finding the right driver for me, similarly to the effort I put in when I get measured up for my irons. 10 mins to find a driver compared to upwards of a couple of hours for a set of irons pretty much says it I guess.

Must.. Not... Comment...

Come on Tim hit us with the sensible views of an engineer, this is an open forum and you have the right to say what you want.

OK, I've got a minute.

The CoR is a ratio of the elasticity of the face and a nominal glass hard ball (the definition of coefficient and therefore dimensionless), the 0.83 is basically the enery yield of the club face under certain circumstances.  In simplistic terms it means that it will only spring back with 83% of the force applied to it.  As the test ball is glass hard, in real terms the CoR is pretty meaningless when it comes to the real world.  It is effectivelly different depending on the type of ball you use, so it will be a lot higher if you use Pinnacle as opposed to a Pro V1, and boththese values will be way less than a non-eleastic ball. Therefore, adding weight will have no effect on the CoR of a club as it is only a nominal value anyway.  It will however effect the Polar Moment of Inertia (usually wrongly called the MoI - see my explanations ad infinitum) depending on where it is added to the head - the further away from the axis of rotation (the shaft) the more the PMoI increases.  The only effect this has is that the instantaneous incidence of loft may change as the head may not be fully unwound on impact and it is more difficult to get the C of G's aligned for the optimum strike.

It is however true that when it comes to the actually energy transfer F=ma will apply, the heavier the head the harder the impact.  The downside is, obviously, that you need to work harder to get the club head up to the same speed and angular position.

zzzz

Ivan

the CoR is dependant on the design of the driver face and the elasticity of the material used, together they give the drumskin effect.  Obviously the maximum CoR can only be reached when the drumskin is deformed to it's design limit, any more and it's counter-productive a the energy is dispelled in other forms (either in the rest of the carcass deforming, the material reaching it's failure point or even the shaft  and other components deforming) - any slower and it's not reached.  It may very well be the case that a lot of drivers reach this point at 110mph, but this a very simplistic way of looking at it.  It would be easy to design a face that has a CoR above unity and then a slower speed swing would be more beneficial (or rather a faster speed would be less use), but this has been deemed illegal.

I would be very interested to see what the CoR of a lot of the smaller steel head drivers, woods and even persimmons are.

Yes sorry Ivan, we do appear to have drifted off the OP (yet) again so I won't dwell on this too much.  Just to say that the easiest way to visualise the CoR is to imagine it as a kettle drum.  Now, drop a ball bearing onto it's centre from a known height and the rebound height will be, say, 83% of the original.  Drop it again from a different height and the rebound will again be 83% - obviously up to the point where the height is above that where the ball reaches it's terminal velocity due to gravity and is no longer accelerating when the rebound height will be constant.  Use a ball of the same mass but coated in a spongy material and the rebound will be a lot lower - the CoR of the drum has not changed but the reaction is a lot less.  The anology also works quite well if you drop the ball off centre, it will tend to rebound towards the centre and induce a spin component to the ball...