A summary of the new grooves rule for golf is as follows:
The amended regulations covering grooves on clubs includes two new provisions. The first reduces the maximum groove volume by about 25% from what is currently allowed. This new restriction is technically described as the total cross-sectional area of a groove divided by the groove pitch (width plus separation) limited to 0.0030 square inches per inch.
The second new provision limits the groove edge sharpness to a minimum radius of .010 inches. There is currently no numerical minimum for edge radius in the rules. The new limit will produce groove edges that are substantially duller than allowed by the current manual test.
All pre-Vokey Design C-C wedges do not meet the design specifications of the new rule. However, current and pre-Vokey Design C-C wedges will remain conforming for most golfers until 2024.
The PGA Tour and most Tour-level competitions have indicated that they will adopt the new groove regulations as a condition of competition beginning 01/01/2010. It remains to be determined if the condition of competition will apply to qualifiers for Tour-level events.
The USGA has stated that the Condition of Competition will be adopted for the US Opens and their qualifiers conducted after 01/01/2010. The R&A has adopted it for the Open Championships, but not for certain of its qualifiers.
Other USGA/R&A Championships will apply the Condition of Competition beginning 01/01/2014. (PGA Club Pro, major Amateur, Collegiate, State Golf Association events).
Tournament Committees at the regional, state, and local club level may adopt the Condition of Competition to require the use of clubs that conform to the new groove rule at any time.
Manufacturers may produce and ship clubs with currently conforming grooves prior to 01/01/2011.
Currently conforming clubs produced and shipped by manufacturers prior to 01/01/2011 may continue to be played for all rounds of golf and for handicap purposes, where the Condition of Competition is not in effect, until 2024.
The final decision regarding the status of these clubs will be reviewed no sooner than 2020. If the USGA/R&A determine at that time (or later) that the rule change should apply to all clubs, there would be a minimum 4-year implementation period.