We hope you love this post on the Tecnifibre X-One Biphase! Just so you know, TennisCompanion may collect a small share of sales from the links on this page to help keep this site running.
X-One Biphase is a premium multifilament string that combines the best of Tecnifibre’s technologies into a single string to produce power, comfort, and gut-like feel.
One of the string’s standout qualities was how comfortable it was to play with. Even strung at a higher tension, X-One Biphase still retains its cloud-like comfort which is great for any players suffering from tennis elbow or simply looking for an all around arm-friendly string.
However, at the end of the day, X-One Biphase’s star quality was its raw power, which is at the top of its class. The ball really jumps off the strings and made for a really fun playtest, especially when I had the opportunity to crank a few winners.
Combine the strings comfort level with its power and it made for a unique combination where the string was naturally comfortable on your arm and you didn’t have to work too hard or strain your arm to generate pace.
While the strings slick coating contributes to its power and comfort level, it did leave us longing for a bit more grip. However, after about 30 minutes or so of playtime and a little extra focus on generating topspin, I began to find my rhythm.
X-One Biphase is an all around a terrific multifilament string that’s great for players looking for extra comfort and some extra pop.
Video Review & Playtest
X-One Biphase Specifications & Rating
|Tecnologies||PU 400 – Elastyl – Biphase|
|Available Colors||Natural white and red|
|Available Gauge||16/1.30mm – 17/1.24mm – 18/1.18mm|
|String Length||Set: 40 feet (12m) Reel: 660 feet (200m)|
|Cost||$$$ – Get it On Amazon|
Where to Buy X-One Biphase
About Tecnifibre X-One Biphase
Tecnifibre’s X-One Biphase is a premium multifilament string that was developed with three key goals in mind: power, feel and comfort.
X-One Biphase comes in three different gauges: 16/1.30mm, 17/1.24mm, and 18/1.18mm. You can also pick it up in natural white or red, which is pretty cool.
Key features for X-One Biphase include:
- PU 400: X-One Biphase is infused with a proprietary polyurethane that delivers 400% greater elasticity and therefore increasing the power potential of the string while reducing vibrations and increasing the overall comfort or impact to your arm with a natural gut-like feel.
- 50% Elastyl, 50% H2C fiber: X-One Biphase is constructed from thousands of individual fibers with a makeup of 50% Elastyl and 50% high heat capacity (H2C). Elastyl is Tecnifibre’s trademarked polyamide or nylon, which are incredibly soft fibers that deliver 12% more power than standard nylon strings, while H2C fibers are manufactured and bonded using a high-temperature pre-stretching step that is intended to provide superior tension maintenance.
- Biphase process: Tecnifiber’s patented two-phase process is used to produce the string, which is intended to increase the durability and life of the X-One Biphase by 20%.
All in all, Tecnifibre’s X-One Biphase packs a technological punch to bring players of all levels a top-notch multifilament string that many will find as one of the best synthetic alternatives to natural gut.
When it comes to packaging Tecnifibre has delivered their X-One Biphase in style. Each string package features a matte black finish with a gold highlight that bears the strings name and gauge.
The bottom right hand corner of the packages front offers a small peak view of the string, while the back of the package showcases the strings key features and useful graphic to help players picture the makeup of the tennis string.
The strings are easily opened with a simple tear from the top left of the packaging that has been perforated for easy opening.
Overall, I really enjoyed stringing with X-One Biphase.
A quick pre-stretch of the strings removed the limited coil memory that was retained by the strings from packaging and made it very simple to maneuver during stringing.
At first, I did expect the thicker 16 gauge that I playtested to give me a little trouble since it’s a soft multifilament, but I didn’t run into a single problem simply making sure to keep a sharp point at the end of the string anytime I ran into a tight spot or blocked hole.
Stringing the crosses were a breeze as the strings slick outer coating helped it easily slide through the mains and because X-One Biphase is a softer multifilament, I didn’t experience any issues tying knots.
X-one Biphase Playtest
Here are a few important stats when playtesting Tecnifibre’s X-One Biphase:
- String: X-One Biphase 16/1.30mm, natural white
- Racquet: Wilson nCode nSix-One 95
- Tension: 60
- Forehand: western grip, heavy topspin
- Backhand: two handed
Overall, I was impressed with the durability of X-One Biphase, which undoubtedly was helped by the fact that I went with the thicker 16 gauge.
Generally speaking, multifilament tennis strings that are designed to be soft on the arm and produce a gut-like feel tend to lack durability to a degree, which is simply a trade off that comes with the territory when you go with this family of tennis strings.
However, I was happy to find that compared to other multifilament strings I’ve playtested, X-One Biphase held up well especially under the heavy topspin of my forehand, which is frequently the cause of broken strings for me.
I intentionally went with the thickest 16 gauge because I’m a chronic string breaker so I appreciate the extra life that this gauge provided me and turns out I was happy for doing so as some slight notching in the strings was apparent even after an hour of play.
I did eventually break the strings after 8 hours of play, but I felt that for the type of string this was a great life expectancy especially considering my style of play.
Helpful Tip: the durability of your tennis strings is dependent on a wide range of factors including the gauge or thickness of the string, the type of grip you hold for your groundstrokes, how hard you hit, the tension you string at and other factors… even include the weather.
As you evaluate tennis strings and the importance of durability compared to other factors like comfort, it’s important to consider your style of play. A big hitting Division 1 college level player may find a particular string doesn’t hold up well to their game, but that doesn’t mean the string isn’t durable especially relative to other strings in the same family.
With tennis strings, it’s frequently about tradeoffs, so make sure you weigh durability appropriately against other factors like comfort.
What X-One Biphase lacks in durability to a small degree it completely makes up for in comfort thanks to Tecnifibre’s proprietary polyurethane PU 400 and the cushiony Elastyl fibers that make up 50% of the strings composition.
The shock absorption of the string was apparent from my first stroke and it was delightfully forgiving even with the higher 60lb tension that I used to control some of the power.
I specifically recall one low forehand that I dug out and hit off center outside of the sweet spot and was surprised by how gentle it was on my arm compared to the shock that I might have felt with a more durable polyester string.
All in all, X-One Biphase is a super comfortable tennis string that would be a great fit for anyone suffering from tennis elbow or simply looking to reduce shock and vibration to their arm perhaps with a stiffer racquet frame.
If there’s one thing that’s going to surprise you about X-One Biphase it’s the string’s raw power; a feature that made it super fun to play with.
Based on Tecnifibre’s specs and some initial research, I expected it to bring plenty of extra power so I intentionally strung it at a higher 60lbs to maintain a bit more control and bring the power level down a bit, but even at the higher tension, the extra pop was still apparent.
Generating extra pace when hitting felt automatic and I never felt like I had to force or will the ball over the net. Where I really enjoyed the power was on my serve where I was able to crank it up and the ball would just jump off the strings.
Helpful Tip: if you’re at all concerned about the added power of X-One Biphase, I’d definitely encourage you to up the tension a bit or my personal approach would be to use X-One Biphase as part of a hybrid setup with control oriented mains.
Control 7.5 & Spin 6.8
As I was getting comfortable with X-One Biphase, one of the challenges that I did find with my groundstrokes was that the string didn’t have the grip that I’m used to with some of the hybrid string setups that I’ll use.
As a result, I found a few extra groundstrokes sailing a few feet long, so I had to adjust and focus on generating more topspin to help keep the ball in play.
After about an hour or so of hitting and once the strings started to settle in a bit I’d say it really wasn’t much of an issue. However, similar to dropping the power level a bit, players that hit with a lot of topspin and expect that extra bite from their strings would likely want to string X-One Biphase as part of a hybrid string setup.
Another option would be to drop down to the 17 gauge strings, which should provide you with a bit more grip although a heavy topspin player might avoid this due to a decrease in durability and life expectancy of the string. If price isn’t much of an issue then this might be a great option for you.
Along with X-One Biphase being an incredibly comfortable string to play with, I found it to be highly responsive, which might be a little counterintuitive with the high power the string offers.
The great touch of the string was not surprisingly most apparent at the net hitting volleys where I felt like I had plenty of control and could easy direct the ball wherever I wanted.
Tension Stability 8.8
Overall, I felt like X-One Biphase did a terrific job of holding its tension, which would have been aided by the pre-stretching that I did before stringing.
The settling that occurs after 30 or so minutes of play is extremely common with many string sets was negligible and I found the strings continued to hold their tension well over the course of my roughly 8-hour playtest.
String Movement 8.7
This one was a bit of a surprise for me. I expected the strings to move much more than they did. After about 15 minutes of play, the strings had barely even budged.
This was of course helped by the higher string tension, but typically I find that my forehand is good for pushing the strings all over the place and even after a full hour of play there was very little movement compared to other multifilaments I’ve played with.
- The Best Tennis Strings for 2017
- A Comprehensive Guide for the Different Types of Tennis String
- How Often Should I Change or Replace My Tennis Racquet Strings?
- Enhance Your Game with the Right Tennis String Tension
- Tennis String Gauge and Its Impact on Performance
Have you used Tecnifibre X-One Biphase? We’d love to hear about your experience in the comments below. Of course, if you have questions we’d love to hear from you too!
Play Better TennisImprove your game alongside our community of tennis players
- Play better tennis with in-depth resources and guides
- Stay up-to-date on tennis news with our weekly tennis report
- Ask questions and get answers from players across the globe