Babolat RPM Blast + RPM Soft Hybrid Tennis String Review

Babolat RPM Blast + RPM Soft is a hybrid tennis-string set designed for developing and intermediate players who want access to RPM Blast’s spin and control without using a full bed of firm co-polyester.

The combination pairs RPM Blast 1.25mm with RPM Soft 1.30mm. RPM Blast is an octagonal co-polyester monofilament, while RPM Soft is a round polyamide monofilament with a softer and more elastic response.

RPM Soft should not be confused with a polyester or multifilament. Its polyamide construction places it closer to nylon-based strings, but its solid monofilament structure gives it a different response from a traditional multifilament.

The hybrid can be installed in two orientations. RPM Blast mains emphasize spin and control, while RPM Soft mains provide more power, pocketing and comfort. The main strings normally have the greatest influence on the overall response.

Players who are unsure whether a hybrid or full stringbed better suits their game can use the Tennis String Finder to compare suitable options.

Babolat RPM Blast + RPM Soft Hybrid Rating

These ratings consider the hybrid within the wider tennis-string market. The final performance will also depend on the racket, string pattern, tension and playing style.

Babolat RPM Blast + RPM Soft Specifications

The combined set measures approximately 12m and is intended for one hybrid installation.

Material, Construction, Shape and Technologies

RPM Blast is an extruded co-polyester monofilament. It consists of one solid synthetic filament rather than the numerous flexible fibers found in a multifilament.

Its octagonal cross-section creates eight sides that can engage the ball during an upward or angled swing. Babolat also uses a smooth, silicone-associated surface treatment intended to encourage string movement and snapback.

The combination of its shaped profile, controlled response and smooth surface makes RPM Blast the spin-focused component of the hybrid. It also provides greater physical resistance to breakage than RPM Soft.

RPM Soft is fundamentally different. It is a polyamide monofilament, not a softer type of polyester. Polyamide is the material family that includes many nylon-based strings.

Babolat describes RPM Soft as more flexible than polyester monofilaments while remaining more physically durable than a polyamide multifilament. Its single-filament construction is reinforced by a double aramid coating.

The aramid coating is intended to improve wear resistance. However, independent evaluations have reported that RPM Soft can notch quickly and that its surface may create more friction than expected when paired with a polyester main.

This interaction is important. Spin does not come only from RPM Blast’s octagonal shape. The mains must also slide across the crosses and return toward position after impact.

If RPM Soft develops notches or prevents the RPM Blast mains from moving freely, the hybrid can lose spin and control even though the strings remain intact.

The two materials therefore create a genuine compromise. RPM Blast contributes bite and control, while RPM Soft adds flexibility, power and comfort. Neither string completely removes the limitations of the other.

Babolat RPM Blast + RPM Soft Performance

Power

RPM Soft supplies most of the hybrid’s additional power. Its more flexible polyamide construction produces easier depth than the firmer RPM Blast.

With RPM Blast in the mains, power remains controlled. The polyester mains dominate the response, while the RPM Soft crosses make the stringbed livelier and less demanding than full RPM Blast.

This orientation should suit players with medium-to-fast swings who want slightly easier depth without losing too much control.

Placing RPM Soft in the mains produces a noticeably more powerful response. The polyamide mains stretch more easily and launch the ball with less effort, while RPM Blast crosses help limit some of that power.

RPM Soft mains can benefit developing players, compact swingers and players using lower-powered rackets. However, the livelier trajectory may require an adjustment from anyone accustomed to full polyester.

Power can increase further as RPM Soft notches or loses its ability to return toward position. When that happens, depth may become less predictable.

RPM Blast mains power rating: 7.5/10

RPM Soft mains power rating: 8.5/10

Spin

RPM Blast is responsible for most of the hybrid’s spin potential. Its octagonal profile provides mechanical bite, while its controlled response allows players to accelerate through the ball.

Babolat recommends RPM Blast in the mains when maximum spin from this combination is the priority. This orientation allows the shaped polyester to interact directly with the ball.

However, RPM Blast’s shape is only one part of spin production. The mains must also be able to slide across the RPM Soft crosses and snap back.

Independent testing of RPM Soft has reported that its coated surface can restrict polyester-main movement. Rapid notching can further reduce snapback as the stringbed ages.

The result is good initial spin, but not necessarily the same spin consistency as a full bed of RPM Blast or a hybrid using a lower-friction cross.

With RPM Soft in the mains, spin is more moderate. The round polyamide mains do not provide RPM Blast’s sharp geometric bite, and their livelier response can make it harder to swing aggressively without overhitting.

RPM Blast crosses still contribute control and may support string movement, but the setup should not be considered an elite spin option.

Players who rely on extreme topspin may prefer full RPM Blast or another polyester setup. This hybrid is better understood as a comfort-oriented compromise with useful spin.

RPM Blast mains spin rating: 8/10

RPM Soft mains spin rating: 7/10

Control

RPM Blast mains create the more controlled orientation. The co-polyester’s firm response limits free launch and allows players with developed strokes to accelerate with confidence.

RPM Soft crosses add some power and pocketing. This makes the stringbed easier to use than full RPM Blast without completely removing its directional stability.

Control is strongest while both strings are fresh and able to move normally. As RPM Soft notches, the launch angle and string movement may become less consistent.

RPM Soft mains create a livelier response. They provide easier depth but less restraint on fast swings. The RPM Blast crosses add stability, although the mains still determine much of the stringbed’s character.

This orientation should be more suitable for developing players than advanced heavy hitters. Players with long, fast swings may find RPM Soft mains too lively, particularly in a powerful racket or open string pattern.

Dense string patterns can help control RPM Soft’s launch and reduce excessive string movement.

RPM Blast mains control rating: 8.5/10

RPM Soft mains control rating: 7.5/10

Comfort and Feel

RPM Soft makes this hybrid more comfortable than a full bed of RPM Blast. Its flexible polyamide construction adds pocketing and reduces the rigid sensation associated with firm polyester.

With RPM Blast in the mains, the response remains relatively crisp and controlled. RPM Soft crosses soften the overall feel, but they do not completely remove the firmness of the polyester mains.

This configuration can work for experienced RPM Blast users who want a less demanding stringbed without abandoning its control-oriented response.

RPM Soft mains create the more forgiving arrangement. The softer mains dominate impact, producing deeper pocketing, easier depth and a less rigid sensation.

The RPM Blast crosses prevent the setup from feeling as powerful as a full bed of RPM Soft. They also preserve some of the direct response associated with polyester.

RPM Soft is comfortable relative to polyester, but this hybrid should not automatically be described as safe for every player experiencing elbow, wrist or shoulder discomfort. Racket stiffness, tension, technique and previous injury all remain important.

RPM Blast mains comfort rating: 7.5/10

RPM Soft mains comfort rating: 8.5/10

Durability and Tension Maintenance

RPM Blast provides the greater physical resistance to breakage. Its co-polyester construction is designed for players who hit with pace and regularly wear through softer strings.

RPM Soft’s monofilament structure makes it more durable than many polyamide multifilaments. Its aramid coating is also intended to improve wear resistance.

However, resistance to complete breakage should not be confused with resistance to notching. Independent evaluations have found notching to be RPM Soft’s main weakness.

With RPM Blast in the mains, the polyester can cut grooves into the softer RPM Soft crosses. These grooves can lock the mains in place and prevent normal snapback.

With RPM Soft in the mains, the round polyamide strings can notch against the firmer RPM Blast crosses. The setup becomes more comfortable, but physical durability may decline for heavy topspin hitters.

Babolat states that combining the two strings reduces friction-related heat and improves durability. In practice, the result will depend on the racket and player. Open patterns, heavy spin and frequent string movement can accelerate RPM Soft’s wear.

Tension maintenance and playability duration must also be separated. RPM Soft has demonstrated good tension retention, but independent playtesting found that notching and string displacement could reduce useful playability before tension loss became the primary problem.

RPM Blast presents the opposite concern. It may remain physically intact after losing elasticity and its original response.

The hybrid can therefore stop performing properly even when neither component has broken. Warning signs include:

• The strings remaining out of position
• Reduced snapback
• Deep notching at string intersections
• A changing launch angle
• Less predictable depth
• Reduced spin
• A firmer or less responsive feel
• Excessive string movement
• Difficulty controlling faster swings

The setup should be replaced when these changes become noticeable. Waiting only for breakage can leave a player using a stringbed that no longer performs as intended.

The guide explaining how often to change tennis strings covers the difference between physical lifespan and useful playability in greater detail.

Choosing the Right Gauge

The packaged RPM Blast + RPM Soft hybrid comes in one fixed combination.

The 1.25mm RPM Blast provides a practical balance of bite and durability. It is thin enough to remain responsive while preserving the controlled qualities of co-polyester.

The 1.30mm RPM Soft is thicker because it is the softer and less wear-resistant component. Its additional material helps it withstand contact with the firmer RPM Blast.

Players cannot change the gauges within the packaged hybrid. A custom combination requires purchasing full sets or reels of the individual strings.

Using a thicker RPM Blast would create a firmer and more break-resistant setup. A thinner version would feel more responsive but could wear the RPM Soft more aggressively through increased movement.

A thinner RPM Soft would provide more feel and response, but its notching and physical durability could become greater concerns.

For most players interested in this exact hybrid, the supplied 1.25mm and 1.30mm combination is the correct starting point.

Full Bed or Hybrid Setup

RPM Blast Mains With RPM Soft Crosses

This is the more control and spin-oriented configuration. It is also Babolat’s recommended orientation when maximizing spin from the hybrid is the priority.

RPM Blast mains provide:

• Greater control
• More direct ball bite
• Better resistance to breakage
• A lower-powered response
• Greater confidence on fast swings

RPM Soft crosses provide:

• Improved comfort
• Additional pocketing
• Easier depth
• A less rigid overall response

The main limitation is friction between the two strings. RPM Soft crosses may restrict RPM Blast’s movement or develop notches that reduce snapback.

This orientation is most suitable for moderate-to-fast swingers who want more comfort than full polyester but do not require maximum spin consistency.

RPM Soft Mains With RPM Blast Crosses

This orientation emphasizes power, comfort and pocketing. The flexible polyamide mains dominate the response, while RPM Blast crosses add control and stability.

RPM Soft mains provide:

• Easier depth
• A softer impact sensation
• More ball pocketing
• Greater accessibility for developing players
• More power on compact swings

RPM Blast crosses provide:

• Additional control
• A firmer supporting response
• Some polyester durability
• Reduced launch compared with full RPM Soft

The primary concern is notching. RPM Soft mains can wear against the firmer, octagonal RPM Blast crosses, particularly when the player generates heavy spin.

This orientation is better for developing and intermediate players than advanced string breakers. It can also work well in dense string patterns where movement is more limited.

Full Bed Alternatives

The packaged set contains two half lengths intended for hybrid installation. Each half is generally insufficient for a complete stringbed.

A full bed of Babolat RPM Blast provides greater spin consistency, control and break resistance. It is also firmer, lower powered and less forgiving.

A full bed of Babolat RPM Soft provides more power, comfort and pocketing. It also experiences more movement and notching than co-polyester.

Players who want RPM Soft mains with a lower-friction cross may consider pairing it with a smooth synthetic gut or multifilament. This may allow the mains to move more freely than they do against another sticky or heavily textured string.

General Tension Guidance

Both strings should be installed within the tension range approved by the racket manufacturer.

RPM Blast is firmer and less elastic than RPM Soft. It is commonly installed at a lower tension than softer nylon-based strings to avoid creating an unnecessarily rigid response.

RPM Soft is livelier and more powerful. Its suitable tension depends on whether the player needs easier depth or greater control.

With RPM Blast in the mains, beginning in the lower-to-middle portion of the racket’s approved range can preserve comfort and pocketing. Excessive tension may reduce the main reason for using RPM Soft crosses.

With RPM Soft in the mains, a slightly firmer setup within the approved range may help manage its launch. However, increasing tension can also create a firmer feel and should not be used as the only solution for an unsuitable string.

Powerful rackets and open string patterns may require a more controlled setup. Dense patterns and low-powered rackets can usually accommodate a lower tension.

Change only one variable at a time. Keeping the orientation and gauges consistent while making a small tension adjustment provides clearer information than changing the entire setup.

The Tennis String Tension Calculator can provide a general starting point based on the racket and playing style.

Who Should Use This Hybrid?

Babolat RPM Blast + RPM Soft is best suited to:

• Developing and intermediate players
• Players beginning to explore monofilament strings
• Players transitioning from multifilament to polyester
• RPM Blast users seeking more comfort
• Moderate topspin players
• Players with medium swing speeds
• Players who want a balance of control and accessible power
• Players who prefer a hybrid without natural gut
• Players using dense or moderately open string patterns
• Juniors transitioning toward firmer performance strings under suitable guidance
• Players who do not regularly break strings

RPM Blast mains suit the faster and more control-oriented player. RPM Soft mains suit the player needing easier depth and comfort.

Who Should Avoid This Hybrid?

This hybrid may not be suitable for:

• Advanced heavy topspin hitters seeking maximum snapback
• Frequent string breakers
• Players who require the physical durability of full polyester
• Players who want the maximum comfort of natural gut or multifilament
• Players who dislike string movement
• Players who need exceptionally long playability duration
• Players using very open patterns with aggressive spin
• Players seeking a consistently low launch angle
• Players who leave worn or notched strings installed indefinitely
• Players assuming a softer cross makes every polyester setup suitable for an injured arm

Complete beginners may not need the complexity of a hybrid. However, Babolat specifically positions the combination toward developing players, so it should not be dismissed simply because a player is not advanced.

Babolat RPM Blast + RPM Soft Pros and Cons

Babolat RPM Blast + RPM Soft Compared With Other Setups

The Touch VS hybrid provides the more premium combination of power, comfort and tension stability. RPM Blast + RPM Soft is easier to maintain, less sensitive to weather and more accessible financially.

Compared with full RPM Blast, the RPM Soft hybrid is more comfortable and powerful but does not provide the same reliable snapback or break resistance.

Final Verdict

Babolat RPM Blast + RPM Soft is a comfort-oriented hybrid intended to make RPM Blast more accessible to developing and intermediate players.

Its two components are materially different. RPM Blast is an octagonal co-polyester monofilament designed for spin and control. RPM Soft is a round polyamide monofilament with a double aramid coating, designed to provide more flexibility than polyester.

RPM Blast mains create the stronger configuration for control and initial spin. RPM Soft mains produce more power, pocketing and comfort.

The previous 9/10 spin rating was too generous. RPM Blast provides good bite, but independent evaluations have found that RPM Soft can restrict main-string snapback and notch quickly. Spin and control may therefore decline before either string breaks.

The previous durability assessment also needed more context. RPM Soft can hold tension well and resist complete breakage, but notching can shorten its useful playability.

This is not a replacement for full RPM Blast when maximum spin, control and durability are required. It is also not as powerful, comfortable or tension-stable as a premium natural-gut hybrid.

For developing and intermediate players who want a manageable introduction to polyester performance, the combination makes sense. RPM Blast mains provide the more competitive response, while RPM Soft mains provide the more forgiving setup.

Frequently Asked Questions

Is RPM Soft a polyester string?

No. RPM Soft is a polyamide monofilament. It is more flexible than polyester and co-polyester monofilaments.

Is RPM Soft a multifilament?

No. It uses a single-filament construction rather than a bundle of individual fibers.

What does the hybrid set include?

It contains approximately 6m of RPM Blast 1.25mm and 6m of RPM Soft 1.30mm, providing enough material for one hybrid string installation.

Which string should go in the mains?

Use RPM Blast in the mains for greater spin, control and break resistance. Use RPM Soft in the mains for more power, comfort and pocketing.

Which orientation does Babolat recommend?

Babolat recommends RPM Blast mains when maximizing spin from the combination is the priority. The strings can be reversed to create a softer and more powerful response.

Does this hybrid provide maximum spin?

It provides good initial spin with RPM Blast in the mains. However, RPM Soft can restrict snapback and develop notches, so spin consistency may be lower than with full RPM Blast.

Is it more comfortable than full RPM Blast?

Yes. RPM Soft adds flexibility and pocketing, making either orientation more comfortable than full RPM Blast.

Is it suitable for arm-sensitive players?

It may be more comfortable than full polyester, but RPM Blast remains a firm co-polyester. The hybrid should not automatically be considered suitable for every player with arm discomfort.

Is RPM Soft arm-friendly?

It is comfortable relative to polyester, but “arm-friendly” should not be treated as a guarantee against pain or injury.

How powerful is the hybrid?

Power is moderate with RPM Blast mains and higher with RPM Soft mains. The latter orientation is better for players who need easier depth.

How durable is the hybrid?

RPM Blast has strong break resistance, while RPM Soft is less durable than co-polyester. Physical lifespan depends on orientation, string pattern and playing style.

Does RPM Soft maintain tension well?

RPM Soft can maintain tension well. Its more significant playability issue is notching, which can reduce string movement, spin and control.

Why do the strings stop snapping back?

Grooves can form where the mains and crosses contact. These notches lock the strings together and prevent normal movement.

Is the hybrid suitable for beginners?

It can suit developing players, particularly those transitioning toward monofilament. Complete beginners may be equally well served by a simpler multifilament or synthetic-gut setup.

Is it suitable for juniors?

Babolat positions RPM Soft and this hybrid toward developing players. Junior equipment decisions should still account for age, technique, racket and coaching guidance.

Is it suitable for advanced players?

It can work for advanced players seeking more comfort, but heavy topspin hitters may find its snapback and playability duration insufficient.

Can frequent string breakers use it?

RPM Blast mains provide reasonable durability, but frequent string breakers may wear through or deeply notch RPM Soft. Full co-polyester will normally provide greater physical resistance.

Can either half be installed as a full bed?

The individual half sets are generally too short for a complete string installation. A full set of the selected string must be purchased separately.

Is this hybrid better than RPM Blast + Touch VS?

It is easier to maintain and less expensive, but Touch VS provides greater power, feel, comfort and tension stability. The natural-gut hybrid is the more premium setup.

When should the hybrid be replaced?

Replace it when notching becomes deep, the strings remain displaced, spin declines or depth becomes unpredictable. Do not wait only for complete breakage.