The R&A
St Andrews, Fife
Scotland KY16 9JD
Tel: +44 (0) 1334 460000
Fax: +44 (0) 1334 460152
www.randa.org
www.opengolf.com

22 September 2008
NOTICE TO MANUFACTURERS

PROPOSED REVISION OF INTERPRETATION AND EVALUATION OF SPRING FEATURES WITHIN
CLUBHEADSOn 28 May 2008, The R&A proposed a new test method for evaluating future clubhead
submissions to determine whether they contain features or technology that are designed
to influence, or have the effect of influencing, ‘spring effect’.
As you know, Appendix II, 4c states that:
Spring Effect and Dynamic Properties
The design, material and/or construction of, or any treatment to, the clubhead(which includes the club face) must not:
(i)
(ii)
(iii)

have the effect of a spring which exceeds the limit set forth in the Pendulum
Test Protocol on file with the R&A; orincorporate features or technology including, but not limited to, separate
springs or spring features, that have the intent of, or the effect of, unduly
influencing the clubhead’s spring effect; orunduly influence the movement of the ball.

This revised language was introduced in January 2008, to reflect more accurately TheR&A’s interpretation of ‘spring effect’ – i.e. whilst the conformance of a club to thePendulum test is necessary (see clause (i) above), this test is not sufficient to assess
whether a club incorporates a feature which might influence its ‘spring effect’ (see clause(ii)). The revised wording was prompted by a number of clubhead submissions which were
found to incorporate spring features but did not exceed the limit for ‘spring-like’ effect asmeasured by the Pendulum Test. Under the pre-2008 wording of the Rule, it was not clearto all manufacturers as to why such a club should be ruled non-conforming. However, it
was always our intent that designs which include features that are designed to act like aspring, independent of the level of flexibility achieved by the design, should be ruled nonconforming.
With the new wording in place, the purpose of the proposal contained in the May
memorandum was to put forward a test by which a submitted club could be evaluated,solely based on its performance on the Pendulum rather than by evaluating the designand construction of the club in other ways.

The R&A
St Andrews, Fife
Scotland KY16 9JD
Tel: +44 (0) 1334 460000
Fax: +44 (0) 1334 460152
www.randa.org
www.opengolf.com

All of the comments received from manufacturers have been carefully considered and,as a result, further investigative work is being carried out. Therefore, at this time, please beadvised that no final decision has been taken as to whether to adopt the proposed test
protocol. However, whilst we conduct additional evaluation of the proposed method and,
until this is completed, The R&A’s Equipment Standards Committee has decided to adopt
the following interim method to determine whether a club conforms to Appendix II, 4c:
1. The characteristic time (CT) of all driving clubs will be routinely measured at otherlocations on the face, in addition to at the centre of the face. This evaluation
method may also be applied to other clubs.
2. Clubs which measure less than or equal to 239 microseconds (plus test tolerance of18 microseconds) at all of the locations tested will be determined to conform to theRules of Golf. This is provided the club also satisfies all of the other specifications set
down in Appendix II, including the requirements that the clubhead must be ‘plain inshape’ and all parts must be fixed.
3. Any club which has a CT measurement greater than 239 microseconds (plus test
tolerance of 18 microseconds) at any location on the face, other than the centre,
will be subjected to further analysis and evaluation as to whether it is deemed toincorporate a spring feature. A club which measures above the limit plus thetolerance in the centre of the face will, of course, be ruled non-conforming.
4. Manufacturers should be aware that any further analysis of a club may cause asignificant delay in the conformance decision and it may require the manufacturer
to submit additional samples and provide detailed information on the productdesign and intent, including a copy of the patent application and planned
advertising material.
This interim method of testing will be effective immediately and, as already stated, work
will continue on the evaluation and/or development of the method proposed in our May
memorandum.
Any questions on the above should be sent to The R&A, marked for the attention of Dr
Steve Otto, Director – Research & Testing, The R&A, St Andrews, Fife, KY16 9JD, Scotland orby email to steveotto@randa.org.