String comparison
RPM Blast vs 4G
Babolat RPM Blast against Luxilon 4G: ratings, specs and which one fits your junior.
The short answer
Both are polyester strings. RPM Blast leads on spin. 4G leads on durability and tension hold. They score the same for arm friendliness (2/5).
Ratings
Power
Spin
Control
Comfort
Durability
Tension hold
Ratings are on a 1–10 scale. The higher score is in bold when they differ.
Pick RPM Blast if…
- You want more spin (10 vs 8 out of 10)
- Best for: heavy topspin players
- Best for: advanced juniors with fast, full swings
- Best for: players who generate their own power
Pick 4G if…
- You want more durability (9 vs 7 out of 10)
- You want more tension hold (10 vs 5 out of 10)
- You restring often and want it cheaper to keep up (cost score 4/5 vs 3/5)
- Best for: control-oriented advanced juniors
- Best for: players who hate restringing frequently
- Best for: players who value precision over power
Specs side by side
| Spec | RPM Blast | 4G |
|---|---|---|
| Type | Polyester | Polyester |
| Construction | Octagonal high-density co-polyester monofilament | Co-polyester monofilament with poly-ether-ether compound |
| Gauges | 16, 17, 18 | 16, 16L |
| Stiffness | Medium high | High |
| Set price | $20–21 | $21–22 |
| Reel price | $130–150 | $170–200 |
| Arm friendliness | 2/5 · Low | 2/5 · Low |
| Cost to maintain | 3/5 | 4/5 |
| Recommended from | Age 14 | Age 14 |
| Levels | Advanced, Elite | Advanced, Elite |
| Play styles | Baseliner, Big hitter | Baseliner, All court |
| Junior tension | 46-50 lbs for juniors. String lower to unlock spin potential. Loses tension quickly so some players string 2-3 lbs higher. | 48-52 lbs for juniors. Better tension maintenance means more consistent feel over time. |
RPM Blast in short
Babolat RPM Blast is one of the most iconic co-polyester strings ever made. When Rafael Nadal showed up at the 2010 Australian Open with this octagonally shaped co-poly, it changed the game. The octagonal structure with high-density co-polyester adds phenomenal rotation to the ball. The slick surface enables the strings to snap back with vicious force, resulting in extra RPMs. One of the most popular co-polys of all time, this firm and durable string is perfect for big hitters looking to load the ball with pace and spin.
4G in short
Luxilon 4G was designed with one goal: better tension maintenance than ALU Power. Made with Luxilon's magical poly-ether-ether compound, 4G strings feature best-in-class durability, control and tension maintenance. Unlike many polys that go dead after 8-10 hours, 4G keeps its feel and control far longer. Its tension holding score of 100% isn't marketing hype - it's backed up by lab data. Control is where 4G shines, making it a workhorse that's reliable, consistent, and built for precision.
RPM Blast vs 4G: quick answers
Which has more spin, RPM Blast or 4G?
Babolat RPM Blast, with a spin rating of 10/10 against 8/10.
Which is more arm-friendly for a junior?
They score the same, 2/5. RPM Blast is recommended from age 14 and 4G from age 14.
Which lasts longer?
Luxilon 4G rates 9/10 for durability against 7/10.
Which is cheaper?
RPM Blast costs about $20–21 a set and 4G about $21–22, at typical retail.
The short answer and the "pick if" lists are generated from our ratings and junior data only. Data verified 2025-01 (RPM Blast) and 2025-01 (4G).