4G Soft is softer than 4G. Where does 217.2 sit among 1.25 mm strings?

4G Soft 1.25 recorded a dynamic stiffness of 217.2 lb/in in the Tennis Warehouse University report saved on September 8, 2026. The same report put 4G 1.25 at 258.9, Element 1.25 at 208.0 and Head Velocity MLT 1.25 at 153.2, all under the selected 51 lb reference tension and Fast setting. The word Soft therefore has a useful reference point: the original 4G sits above it, while two other named alternatives sit below it.

That matters when a player approaches the product from a different starting string. Someone who already likes 4G and wants a lower stiffness has one question. Someone coming from a nylon string and searching the shop for anything marked soft has another. Put the current string, its diameter and the desired change beside the candidate before deciding whether the family name answers your own problem.

What Wilson means by the softer version

Wilson lists 4G Soft 125 as polyester, with a 1.25 mm diameter, gauge 17 and model number RZ99711. Its product description calls the string over 10% softer than 4G while retaining firmness and the line’s emphasis on tension maintenance. The comparison target is explicit: 4G. The manufacturer presents the product to powerful hitters seeking control and consistency, which is a more specific starting point than a general comfort category.

Keep the millimetre specification attached to the name when searching. The archived laboratory report calls the original comparison string 4G 16L (1.25), while Wilson’s Soft product page uses gauge 17 for 1.25 mm. Selecting both by their stated diameter gives the intended pair. Searching only for a gauge number can accidentally place another thickness beside the one you meant to investigate.

Four rows, one comparison condition

Subtracting 217.2 from 258.9 gives 41.7 lb/in. Dividing that difference by the original 4G value gives 41.7 ÷ 258.9 × 100, or approximately 16.1% lower stiffness for Soft. The denominator matters: this is the reduction relative to 4G, using those two rows. It gives a numerical answer to the family comparison without turning the product name into a universal ranking.

The wider comparison then changes the buying question. In the same report, 217.2 remains above Element’s 208.0 and Velocity MLT’s 153.2. A player moving from original 4G would be moving downward in this table; a player moving from either of those two alternatives would be moving upward. Start with that direction before considering whether the trade fits the shots and response you already know.

Why lb/in and the machine’s lb number answer different questions

Dynamic stiffness describes resistance to rapid stretching during impact. TWU expresses it as pounds of force per inch of extension. Reference tension is the load selected for the measurement condition, expressed in pounds. A stiffness value of 217.2 lb/in therefore belongs in the comparison table; the machine setting belongs in the installation record. Copying one number into the other field would confuse a response property with a setup input.

TWU’s explanation also separates a slowly pulled string from its response during a fast impact. A string can stretch readily while being installed yet resist a brief impact differently. This is why handling a loose piece or pressing a thumb into a finished stringbed gives a different sort of information from the dynamic measurement. Use the measured column for the specific property it describes, then record the whole racquet’s response on court.

The completed stringbed adds geometry to the material. Main and cross lengths, the number of strings, frame shape and the installation tension all contribute to its response. Changing from one head size or pattern to another at the same time as changing the string introduces several explanations for a new feel. Keeping the racquet constant gives the string comparison a clearer purpose and makes the next decision easier to repeat.

Choose the next candidate from the starting point

For a regular 4G user, the 1.25 mm pair is a focused first comparison. Write down the feature worth keeping, such as a familiar depth response on a full groundstroke, and the feature you want to change, such as the sharpness of contact on a compact return. Those are observation questions for your own session. The laboratory difference explains why trying Soft may be a reasonable next step; your existing setup supplies the reference for judging the result.

For someone using Element 1.25, the table points the other way. 4G Soft has the higher dynamic-stiffness value of that pair. If the sole aim is to move downward on this particular property, the proposed swap runs against the recorded comparison. If there is another priority, identify it explicitly and seek evidence for that priority instead of asking the word Soft to stand for every aspect of play.

For a player using Velocity MLT 1.25, both the reported material category and the stiffness entry change. The move is from a nylon-labelled row at 153.2 to a polyester-labelled row at 217.2. That is a broader equipment change than moving within the 4G pair. A player who already has a comfortable, predictable nylon setup can first ask which specific limitation requires a polyester candidate, making that requirement part of the buying decision.

Make a useful personal comparison record

Begin with a fresh installation of the familiar string as the reference. A long-used string has already experienced time and repeated impacts, and TWU explains that tension changes with both. Comparing that aged installation with a fresh candidate would mix the product change with its time in use. Record the stringing date and use the same installer and machine process where practical, so the comparison retains a clear starting condition.

• Record the full product name, diameter, racquet, main/cross arrangement and installation setting. Ask the stringer to choose an appropriate setup within the frame and product guidance; keep the laboratory’s 51 lb label in the research notes.
• Select shots that answer the stated question: a compact return for contact response, a routine rally ball for depth, and a fuller swing for the response you want to keep. Use comparable balls and feeds so the equipment change remains interpretable.
• Write separate observations for contact feel, ball trajectory and landing depth. A ball finishing long and a contact feeling firm describe different events; recording both helps identify which part of the setup deserves attention.
• Repeat the same observations after further use and note the playing time. If one candidate changes sooner, the record now contains a time-dependent response rather than only a first impression.

Choose a set before committing to a reel when the main question is still unresolved. The smaller purchase lets the first installation answer whether the candidate deserves a longer place in your setup. Once a preferred combination is established, retaining the complete product and diameter record also makes later restringing more consistent than ordering by colour or by a shortened family name.

Give the word Soft a reference

The four rows support a precise decision: 4G Soft is the lower-stiffness option in the named 4G 1.25 pair, and the higher-stiffness option relative to the two other examples here. That is enough to sort several shopping intentions before a racquet is strung. The next step is to match that direction to a specific change you want, then keep the installation and observation record that will tell you whether the change helped.