Category Archives: Tension

Head Graphene 360+ Radical S v21

From our perspective the Radical S should be one of the most used of the Radical Series!

Head Graphene 360+ Radical S

Why?  The 102 square inch head size is optimum for players looking for additional power,( and who isn’t) in a legitimate players racquet.  We say “legitimate” because this racquet can be turned into any thing you want, now or in the future!

As you will see in the specifications this is not a really stiff racquet so it will be easy for many players to customize the string bed to suit current playing style with an eye toward becoming a more aggressive player, or not!

The Radical S continues with the “control pattern” and “sound grommets”.  We are not totally certain what the “sound grommets” do but sound is frequency and frequency can be felt so maybe the grommets are damping out some of the higher frequencies?

Anyway, this Radical S model is a great step into the “performance” racquet arena with plenty of room to grow!


Head Graphene 360+ Radical S v21
Racquet ModelHead Graphene 360+ Radical S v21
Reference Tension55 lbs - 24.9 k
String: Main/Cross
Victrex 7718
Machine UsedTT Professional
ASPS, FlexFour61.5
Racquet Flex, RDC61 - After stringing
Racquet Flex, FlexFour50
Weight, Grams296
Weight, Ounces10.44
Balance, mm333
Balance, Inch13.11
Length, Cm68.5
Length, Inch26.968
Head Width9.860
Head Length13.09
Head Area, cm2653.9
Head Area, Sq. Inch101.3
Beam Width, mm, Shaft, Center, Tip22, 25, 23
In Plane Stiffness, Pounds/In370.4 Lbs/In
In Plane Stiffness, Kg/cm66.2 Kg/cm

Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.634
Main String Grid7.30
Cross String Grid9.75
Density (% of head filled with string).703
Average Cross String Space.513
Average Main String Space.449
Dynamic Tension, Kp, ERT35
Dynamic Tension, Lbs/in195.8
First Moment, Nm.764
Polar Moment320
Torsional Stability17
Swing Weight, Kg/cm2303
Swing Weight, Ounces10.69
Swing Weight Calculated328
Power, RDC42
Control, RDC60
Manueverability, RDC85
Power, Calculated 1873.1
Head Points2.99 (negative = head heavy)
Head Weight, %48.6%
Center of Percussion21.2
Dwell Time, ms, No Swing8.58
Effective Stiffness - lbs28.9
K, Lb/In (SBS) RDC176.28
Recoil Weight144.50
Twist Weight214.65
End Weight113.1
Tip Weight183.4
Total Weight296.5
9 O'Clock92.1
3 O'Clock91.8
Butt Cap112.2
Total Weight296.1

Head Graphene 360+ Radical Series Comparative Data

For 2021 there are Three (3) Radical Models!

Click Here to See Radical Series Comparison Data

Radical MP v21

A Close Look at Orange

The new, for 2021, Head Graphene 360+ Radical series is a radical step into colors that have always been the “mark” of the Radical Series but now it has gone even further into radicalism!

We think that is a good thing!  Why mess around with just a little orange when you can go all out!

It is impossible to see the vibrancy of this orange without holding it in your hand!  We invite to to hold one in your hand and even hit with it!

The Radical MP has been the most popular model over the years.  This model has all the attributes of the Pro without the added weight, (which can be added later if needed)!

The thin beam carries over to the MP and Pro while the S has a slightly wider beam.

The S model fits the very necessary range of 102 square inch racquets because Head has, correctly, reduced the number of head sizes per model.  The Speed series has the 100 square inch head size very well covered.

You will see all the specifications on each individual review that will be posted shortly.




Head Graphene 360+ Radical Pro

Head Graphene 360+ Radical S

Consistency. What Does It Look Like?


Consistency is a component of almost every successful thing we do each day!

But, what does it look like? Well since this is a tennis centric post it will look like this:

What you are looking at is identical racquets, identical string, identical failure location!

If you find the very end of each string you will see how consistent this failure location is.

This string is a high elongation material so will notice that the ends of the broken strings are very far apart.

This is a good thing since it (elongation) contributes to comfort and power when hitting the ball.

This consistency may be why this player has a UTR of 13.3!

This failure location indicates the player is striking the ball with consistency!  That many explain the UTR of 13.3!

What else does this failure location show us?

  • Most impacts are not in the center of the racquet.
  • The string spacing in this area is a little more “open” which may “catch” the ball and contribute to rotation.
  • There are more strings for the ball to “roll” over before leaving the racquet which may contribute to rotation.

Consistency is important in everything we do.  Visualize it like the string bed of this racquet and try to hit the same spot each time you do something…anything!


See What We are Talking About?

If you have been listening to the Racquet Quest Podcast you know we have talked about what to NOT accept when you pick up your newly strung racquet.

We know it is hard to visualize sometimes so these pictures are posted to give you a visual aid!  This is the very same string!  One could conclude from these images that the person responsible for these knots has not had any training at all.  It makes you wonder how good the rest of the string job is!

Bad Knot

In the interest of improving all stringing, please do not accept this kind of work.  

The image below shows the “dreaded” crossover!  This is not only a potential string damaging error it indicates a lack of skill, or understanding, of doing a good job!

Of course, mistakes do happen but it is the responsibility of the stringer, in this case, to correct the mistake before the client comes to collect their racquet!

Be Prepared!

Be Prepared!

It sure sounds simple but is it?  Not really!  When talking about tennis preparedness that means having enough racquets ready for the tournament,  organizing training sessions, plenty of shirts, shoes, and socks, of course!

But, what’s missing?

Your string is missing!  Sure, you have done a great job of getting your racquets ready but I don’t see several sets of the string you use in the bag!  Why not?  You may believe they will have it at the tournament site, and, if you are using a commodity string, you may be right!

But what if you’re using a high performance string that is set up for your playing style?

  1. Take a few sets of your preferred string with you.  I prefer sets over reels but that is up to you.
  2. Tell the stringer exactly what you want.  That means knowing what you want so be prepared!
  3. Request that your racquet be strung using two (2) pieces of string and the cross strings be started at the top of the racquet.  No exceptions!  No ATW’s, No natural one-piece, simply two pieces top to bottom!

Know how to identify the correct stringing procedure!

Know how to identify the correct stringing procedure and don’t accept anything that is not up to your standards!

Most qualified stingers will appreciate your input and do the proper job for you!

Today a racquet came in that was strung at a tournament that missed the mark!  One-piece ATW, sloppy knots, distorted head shape, and a string that is not used by the player!

That is why we are posting this… “Be Prepared”