Racquet Specs Glossary

A quick reference for every specification you'll encounter on Arcus and in racquet discussions.

Racquet Specifications

Balance Point The point along the racquet's long axis where it would balance on a fulcrum. Expressed in mm from the butt or in "points" head light (HL) or head heavy (HH). See Balance Point.

Beam Width (mm) The cross-sectional depth of the frame, measured at the widest point (usually the head). Wider beams = more stiffness. Narrow beams (< 22 mm) are associated with player's racquets; wide beams (> 26 mm) with power/game-improvement frames.

DT (Dynamic Tension) A measurement of actual string bed stiffness on a strung racquet, taken with a DT830 device. Expressed in kg. More meaningful than reference tension because it reflects the current state of the strings, not what was set on the machine.

Grip Size The circumference of the handle grip, in sizes L1–L5 (European) or 4⅛"–4⅝" (US). Choose a grip that fits your hand — too small causes over-gripping; too large limits wrist snap.

Head Size (sq in / cm²) The area of the strung string bed. Larger heads = larger sweet spot, more power, more forgiving. Smaller heads = more control, more precision, smaller sweet spot.

| Head Size | Classification | |---|---| | < 95 sq in | Small / player's | | 95–100 sq in | Mid-plus (most popular) | | 100–107 sq in | Standard / all-court | | > 107 sq in | Oversize / game improvement |

I (Swing Weight / Moment of Inertia) Resistance to angular acceleration during a swing, measured at the 10 cm pivot point. Units: kg·cm². See Swing Weight.

MgR/I (Recoil Weight) A dimensionless ratio of gravitational torque to moment of inertia. Higher = more maneuverable relative to stability. See Swing Weight.

RA (Stiffness) Frame stiffness as measured on the Babolat RDC. Higher = stiffer. Ranges from ~50 (very flexible) to ~75+ (very stiff). See Frame Stiffness.

RDC (Racquet Diagnostic Center) The Babolat device used as the industry standard for measuring weight, balance, and stiffness. Most specs cited on Arcus are from RDC measurements.

Strung Weight vs. Unstrung Weight Unstrung weight excludes strings and overgrip. Strung weight (most relevant for play) includes strings (~15–17g typically) and whatever overgrip and dampener you use.

String Pattern The number of main (vertical) strings × cross (horizontal) strings. e.g. 16×19.

| Pattern | Effect | |---|---| | 16×19 (open) | More spin potential, slightly more power, less durable | | 18×20 (dense) | More control, flatter ball, more durable, less spin | | 16×20 (semi-open) | Compromise — good control with spin potential |

Twistweight (Polar MOI) Moment of inertia around the long axis. Determines stability on off-centre hits. See Twistweight.

Weight (g) Total strung racquet weight in grams. For play purposes, always use strung weight.

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String Specifications

Co-poly / Polyester A synthetic string made primarily of polyester. Stiff, durable, spin-friendly, poor arm comfort. See String Types.

Elasticity / Elongation How much a string stretches under load. High elasticity = softer feel, more energy return. Low elasticity (poly) = crisper feel, less energy return.

Gauge String thickness, measured in mm or by gauge number (15–18). Thinner = more power and spin, less durable. Thicker = more durable, stiffer, less power.

Hybrid Combination of two different string types in mains and crosses. Most common: natural gut mains + polyester crosses.

Multifilament A string made of many thin fibres. Closest to natural gut in feel and arm comfort. See String Types.

Natural Gut String made from bovine intestinal fibre. Best tension maintenance, best feel, expensive, moisture-sensitive. See String Types.

Reference Tension The tension set on the stringing machine. Not the same as dynamic tension (what you feel when playing) due to immediate and ongoing tension loss.

Tension (lbs / kg) The force applied to each string during stringing. Lower = more power, spin, comfort. Higher = more control, less power. See String Tension.

Tension Loss / Tension Drop The reduction in string tension after stringing. All strings lose tension; polyester loses the most (20–40% within 24 hours).

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Fitting Terms

NTRP (National Tennis Rating Program) US tennis rating system from 1.0 (beginner) to 7.0 (professional). Used in Arcus to match players to appropriate racquet specs.

Power Level A simplification of how much the racquet contributes to ball speed without player input. Mainly determined by swing weight, head size, and string setup.

Sweet Spot The area of the string bed that produces the optimal combination of power and control with minimal frame vibration. Larger head size and higher twistweight both expand the effective sweet spot.