Frequently Asked Questions

What is wrong with the Swingweight method?

The Swingweight method for matching golf clubs within a set of clubs has been in use for almost a century.  This is an easy and very straightforward method for matching golf clubs.  Unfortunately the Swingweight does not in any way relate to the behavior of golf clubs when swung.  Thereby golfers need to learn one swing for each club.

The following should convince anyone that Swingweight is not a useful tool for matching golf clubs.

  • The fact that Swingweight is not measured in a mathematical number system should be a dead giveaway that it is not a physical property.  It is measured in a combination of a letter and a number.  For example C3 and D2.  How much is C3 + D2? Or C3 / D2?  Definitely not a physical property.
  • The Swingweight measuring scale does not have a Zero.  All physical properties have zero value in the absence of the property.  For example if you have 0 Kg of chocolate, you have no chocolate.  Zero Kelvin means that there is no temperature etc.
  • The Swingweight is related to the center of gravity of the golf club.  However the center of gravity of a golf club does not enter the equations describing the motion of a golf club being swung.  It is only relevant when the golf club is static.  Newton's second law of circular motion states: Torque = Moment of Inertia x Angular Acceleration.
  • The Swingweight is measured around a balance point 14" down the shaft.  Why 14"?  Is 14" a physical constant such as for example π (3.14)?  The selection of the balance point is random.  It actually used to be 12", then somebody changed it to 14".  If for example a balance point of 13" or 16" had been chosen instead, golf clubs would have been different.  Still completely wrong, but different.
  • Does it make sense that the Swingweight is increased if one installs a lighter grip?  Similarly, by adding weight to the grip end of a club the Swingweight becomes "lighter".  Add a pound to the grip and your Swingweight would be "superlight".  
  • Club fitters will normally advocate a high Swingweight to large strong persons and a lower Swingweight to small and weak persons.  One way of increasing Swingweight is to install a lighter grip, thereby lowering the overall weight of the club.  Does it make sense that small weak persons should swing a heavier club than a large strong person?

How Do I Install My New Backweights?

Use the shaft access tool to drill the appropriately sized hole in the end of your grip. Insert the backweight, tighten with 4mm hex key, and get ready to improve your game. Here's a handy video that walks you through the whole, simple process:

What is the difference between BioMatch and matching by MOI?

Matching golf clubs by giving all the clubs the same Moment of Inertia around the grip end of the club (MOI) is an improvement over the Swingweight method as it is an exact method of measurement.  Other than that it shares some problems with the Swingweight method:

  • The MOI method does not match the clubs to any particular user.
  • Clubs do not swing around the grip end of the club; it swings around the center of the grip.
  • Making the MOI equal for all clubs does not serve any purpose, unless the weights of the clubs are specified.

It is the relationship between the weight and MOIG that decides how a club behaves.  Further, we do not want all the clubs to behave the same.  Longer clubs needs to be lighter (or the MOIG larger) as you want your hands further forward at impact for longer clubs.  This is where the properties of the golfer come into the picture.

How fast will my game improve after applying BioMatch?

Once you have fitted your weight into the back end of your grips you will notice a difference in how the club feels when you swing it.  Before your first game with your "new" clubs I suggest a session at the driving range to get a feel for how they swing.  When hitting balls at the range try to relax your wrists and trust the clubs without trying to steer them.  You will notice an improvement in your ball striking and game in general already during the first round.  You will continue to improve over time as your subconscious mind is getting used to only handling one swing rather than 13.

Can anyone become a BioMatch Agent?  What is the procedure?

Yes, anyone can become an agent, and there are no exclusive territories. The first step is to purchase an MOIG instrument from Rational Golf. You will then be given the opportunity to sign up as an agent. In order to operate as an agent you need to be able to measure weight, length and MOIG (Moment Of Inertia around the center of the Grip) of golf clubs. A scale for measuring weight and a bench ruler for measuring the length of golf clubs can be purchased through most golf shops, if you do not already have this. Golf clubs can be more accurately matched if the MOIG is measured rather than estimated through our website. As an agent you will measure your customers clubs and input the data into the Rational Golf website. Your customer will decide if he wants to install the weights himself. The weights can be sent directly to the customer or to the agent. Your customer will pay for the BioMatch report and weights on the Rationa Golf website. You charge the customer for the service of making the measurements, entering the data, and installing the weights if applicable. It is up to the agent to decide how much to charge for this service.