How mains and crosses work
A racquet is strung with two string directions: mains (vertical strings running from throat to head) and crosses (horizontal strings that run side to side). In a standard stringing job, both directions use the same string and tension. In a hybrid, the two directions use different string types — and sometimes different tensions.
Why does this matter? The mains and crosses play different roles. The mains see more direct ball contact and generate most of the spin. The crosses primarily hold the mains in position and affect overall stringbed stiffness. Because these roles are different, you can optimize each direction for different properties.
The two most common hybrid configurations
The tour standard
- Maximum power and feel from gut mains
- Poly crosses add spin snap-back
- Better arm comfort than full poly
- Higher cost — but less than full gut
- Federer's setup for most of his career
The accessible entry
- Spin and durability from poly mains
- Gut crosses soften the overall feel
- Modest arm benefit versus full poly
- Lower cost than gut mains configuration
- Good for poly players wanting softer feel
What each configuration actually does on court
Gut mains / poly crosses — the feel
This plays like natural gut with enhanced topspin. The gut mains provide maximum power and feel on contact — the ball sits on the strings longer and releases with more energy. The poly crosses create "snap-back" — when you brush up on a topspin shot, the poly crosses store tension as the mains deflect, then snap them back to position, imparting extra angular velocity on the ball.
The arm benefit here is real: the gut mains do most of the ball-stopping work, and gut absorbs impact energy far better than poly. Players who switch from full poly to gut mains typically report significantly less arm fatigue within two weeks.
Poly mains / gut crosses — the feel
This plays like poly that's slightly softer and more forgiving. The gut crosses add elasticity to the stringbed, but because the poly mains are still doing most of the ball contact, the arm benefit is more modest. This configuration is popular with players who are comfortable with poly's feel but want to reduce harshness without changing their main string's performance profile.
Many players assume poly mains / gut crosses is more arm-friendly than gut mains / poly crosses because gut is "softer." The opposite is generally true — the mains contact the ball first and do more of the energy absorption. Gut where it counts (in the mains) is more arm-friendly than gut where it matters less (in the crosses).
The cost math
| Setup | String cost (approx.) | Labor |
|---|---|---|
| Full polyester | $12–25 | Standard |
| Poly mains / gut crosses | $30–45 | Standard |
| Gut mains / poly crosses | $40–55 | Standard |
| Full natural gut | $55–75 | Standard |
Gut mains / poly crosses costs roughly 60–70% of a full gut job. For players dealing with arm issues, this is usually the most economical path to meaningful arm relief.
Gauge choices for each direction
Gut mains / poly crosses: 17g gut (1.25mm) in the mains for maximum feel and elasticity; 16g or 17g poly in the crosses. Thinner poly in the crosses creates more snap-back movement, enhancing topspin generation.
Poly mains / gut crosses: 16g or 17g poly in the mains; 17g gut in the crosses. Gauge matters less for the gut crosses here — their job is primarily to soften the stringbed rather than optimize performance.
Can you use different tensions in each direction?
Yes — and many players do. A common refinement for gut mains / poly crosses is to string the gut mains 2–4 lbs higher than the poly crosses. The gut naturally plays more powerful (elastic), so raising its tension brings the power level down to match the crosses. This is a calibration move, not a requirement — try the same tension first and adjust from there.
Who should consider a hybrid?
- Players currently on full poly who feel arm discomfort
- Players on full gut who need more durability because the gut mains keep breaking
- Players who want more spin than full gut provides
- Players who want to reduce cost from full gut without giving up gut's feel in the mains
Beginners who break strings rarely aren't the target audience — the extra complexity and cost aren't worth it until you're playing regularly enough to notice the difference. But for anyone hitting 2+ times per week and paying attention to how their setup performs, a hybrid is worth trying.
Gut mains / poly crosses is the setup we recommend most often at Tennis Lab FX for players who want meaningful improvement in arm comfort without giving up spin performance. It delivers most of gut's benefits where they matter most — in the mains — at a fraction of the full gut cost.
We'll build the right hybrid for your game.
Not all gut is the same, and not all poly crosses behave the same. Come in and we'll match the strings to your frame and playing style.