Mizuno Pro S-4 vs S-3: same lofts, more offset in the long irons

Mizuno’s specification sheets for the Pro S-3 and the new Pro S-4 list the same loft, lie and length for every club from the 3-iron to the pitching wedge. The 7-iron in both is 34° and 37.25in. Only the offset column differs, and the difference grows as the clubs get longer: none in the pitching wedge, 0.024in in the 7-iron and 0.043in, about 1.1mm, in the 3-iron.

The S-4 went on sale on 17 September as the third iron in Mizuno’s Signature Series, alongside the S-1 blade and the S-3 cavity back. Mizuno describes it as the most forgiving model in the series and says it was developed “for players who appreciate the feel of a traditional forged iron but want greater confidence”. Beyond the offset, the company says the S-4 has a curved muscle that moves mass lower in the head, and a sole that widens and a centre of gravity that deepens as the irons get longer. Each head is forged in Hiroshima from a single billet of 1025E mild carbon steel, with a copper underlay beneath the chrome.

Offset by club in the three Signature irons

Offset in inches, from Mizuno’s specification pages. The S-1 is not made as a 3-iron.

Club	Loft	S-1 offset	S-3 offset	S-4 offset
3-iron	21°	–	0.130	0.173
4-iron	24°	0.098	0.126	0.165
5-iron	27°	0.094	0.122	0.157
6-iron	30°	0.091	0.118	0.150
7-iron	34°	0.087	0.114	0.138
8-iron	38°	0.083	0.110	0.126
9-iron	42°	0.079	0.106	0.114
PW	46°	0.075	0.102	0.102

From club to club, the S-3’s offset changes by 0.004in. The S-4 changes by up to 0.012in, so by the pitching wedge it has come down to the S-3’s figure. Its 4-iron has 0.067in (1.7mm) more offset than the S-1 4-iron. GOLF.com reports that the S-4 has a new head shape, with a curved muscle where the S-3’s is straight, so the extra offset does not come from bending the S-3’s hosel.

Mixing S-3 and S-4 irons in one set

Chris Voshall, Mizuno’s director of golf, told GOLF.com that an S-3 player might move into the S-4 in the long irons. Because the lofts and lengths are identical, the gapping does not change at the join, but the offset does. In a set with S-4 heads from the 4-iron to the 6-iron and S-3 heads from the 7-iron down, offset falls from 0.150in in the 6-iron to 0.114in in the 7-iron: a step of 0.036in, three times the largest step inside either set.

A 34° 7-iron on the launch monitor

MyGolfSpy says players’ distance irons usually have a 7-iron of about 29° to 30.5°, against the S-4’s 34°. Mizuno’s M-13, a forged iron in its Modern Series announced in January, has a 32° 7-iron, according to Golfalot.

Golfalot’s George Stead tested the S-4 on the course and on a GC Quad launch monitor. His 7-iron averaged 118.5mph ball speed, 19.9° launch, 6,670rpm of spin and 163.5 yards of carry, with a peak height of 106.6ft. His carries ranged from about 158 yards on mis-hits to nearly 172 on his best strikes. He found the long irons easy to launch but the set shorter than he expected, and said the M-13 and M-15 had gone noticeably further in his testing.

GolfMagic’s Georgina Black reviewed the S-4 on the course and published no launch-monitor figures. She rated its feel and control highly, placed it between the S-1 and the M-Series in Mizuno’s range, and warned that the extra offset may not suit golfers whose miss is already to the left.

Voshall told GOLF.com he expects the S-4 to appeal to low single-figure handicappers; Golfalot puts the range at 0 to 8.

Price and availability

In the US, Mizuno sells the S-4 at $215 a club, or $1,505 for a seven-club set from the 4-iron to the pitching wedge, with a True Temper Dynamic Gold Mid 115 S300 shaft. MyGolfSpy lists a Golf Pride Z-Cord as the standard grip. Mizuno’s specification page lists the 3-iron to the pitching wedge in right- and left-handed versions. In the UK, GolfMagic lists the set at £1,289 for the 5-iron to the pitching wedge, and Golfalot gives £215 a club. According to MyGolfSpy, the S-1, S-3, M-13 and M-15 also cost $215 a club in the US, so a mixed set costs the same as a single-model one. Mizuno’s custom options include steel and graphite shafts from True Temper, KBS, Nippon, Mitsubishi, UST Mamiya and Aerotech.

Sources

• Mizuno Golf: Mizuno Pro S-4
• Mizuno Golf: Mizuno Pro S-4 club specification
• Mizuno Golf: Mizuno Pro S-3 club specification
• Mizuno Golf: Mizuno Pro S-1 club specification
• Mizuno USA: Mizuno Pro S-4 Irons, Right Hand, 7 Piece Set
• GOLF.com: Mizuno’s Pro S-4 irons are the Signature Series’ missing piece
• MyGolfSpy: The new Mizuno Pro S-4 irons prove we have an all-new irons category
• GolfWRX: Mizuno expands Signature Series with Pro S-4 irons
• Golfalot: Mizuno Pro S-4 irons review
• Golfalot: Mizuno M-13 irons review
• GolfMagic: Mizuno Pro S-4 irons review