Wilson K Factor Six One Tour 90 Review

Subtle revisions in design, when added together and taken as a whole, can often result in big changes in performance. Roger Federer's new racquet, the Wilson KSix-One Tour 90 is a case in point.

While at first glance it may look like the changes from nCode to KFactor may have happened in the material build up, a close inspection of the KSix-One Tour 90 reveals some other subtle design updates to the racquet, as well.

The new KSix-One Tour 90 takes a page from the Wilson ProStaff Original 6.0 85, the racquet that wrote the book on classic racquet performance. Take a close look at the new handle of the KSix-One Tour 90 and you'll notice a shorter pallet with more of the graphite shaft exposed below the yoke - just as with the ProStaff Original 6.0 racquets.

Although we're not aware of any physical advantages to the ProStaff 6.0 85 like handle pallet, we do know it will silence critics that noticed this difference between the version of the Tour 90s used by Roger Federer and those available to the rest of us.

Another subtle update to the KSix-One Tour 90 is the string spacing in the sweetspot of the racquet. Members of our Talk Tennis message boards were quick to point out that Federer's version of previous Tour 90s had only four cross strings along the PWS bar at 3 & 9 o'clock on the racquet face. The retail versions of the Pro Staff Six-One Tour 90 and the nCode nSix-One Tour 90 both had five cross stings through this area. With the new KSix-One Tour 90 we now get four cross strings, just like Federer.

After taking a close look at the racquet we had to ask, can blending design hints from the ProStaff 6.0 85 with a technology as new and mysterious as KFactor (Wilson still hasn't told us what KFactor is) result in a better Tour 90? And, most importantly, can this blending of old and new enable us to hit the ball like Federer?

To answer these questions (and to take advantage of some terrific California Central Coast weather) we hit the courts for a three-week playtest.


The KSix-One Tour 90 was a hit with our team at the baseline. Offering excellent stability, comfort, feel and control, our playtesters found this stick well suited to advanced level play. Finding more slice than a New York pizzeria with the KSix-One Tour 90 was Ryan. "Hitting groundstrokes with this racquet was exceptionally good. I especially appreciated hitting approach shots with this racquet. I was able to get really good depth on my approaches. The other shot from the baseline that was just really good was the slice backhand. This racquet is the best slicing racquet I have ever used. I was really able to attack with the slice backhand - just like Gonzalez in the Aussie Open was doing. Great racquet from the baseline, both spin and depth were good." Finding himself one with the racquet from the baseline was Jon. "As a big fan of the ProStaff Six-One Tour 90, I had high expectations for this KFactor version. The KSix-One Tour 90 was no disappointment. Consistent is the only way I can describe this racquet. From the baseline, the KSix-One Tour 90's only limitation is the person swinging it. The smallish 90 square inch headsize delivered good topspin, excellent power, and pinpoint accuracy. It was smooth and comfortable to swing, with good ball feedback on impact. I could tell instantly where the ball was going and where on the stringbed the ball impacted."

Busting the felt off the ball with his very first shot with the racquet was Granville. "The always welcome 'thwap' sound greeted me on the first strike - solid as a rock. I was taking full swipes at the ball and crushing them deep into either corner at will. Very comfortable, yet crisp. The swingweight is noticeably higher than my Hyper ProStaff 6.1, but this only inhibited my regular stroke production on two shots (serve - more on that later) and the extreme forehand and backhand topspin short angles where the added swing weight may be delaying, ever so slightly, contact with the ball. This new Tour, in my honest opinion, is far superior to the nCode version of the same racquet. So comfortable was I with this racquet, I was able to come through with a slightly closed racquet face (especially on the forehand) to further drive that ball deep with pace." Spencer found the KSix-One Tour 90 to offer more spin than a politician caught in a hot debate. "I'm not sure there's a better feeling racquet when hit in the sweetspot. The racquet really comes through the ball and drives it. Access to spin was excellent, as well as the level of control. That being said, I had more mis-hits because of the demanding nature of the racquet. I began to tire and fall behind in timing, as the racquet has a heavier swingweight than what I am used to. I also found that as I tired balls would sail on me. I wasn't hitting a full stroke, so I couldn't create enough topspin to help balls land inside the baseline. Though more forgiving than the nSix-One Tour 90, I still felt very penalized from results of off-center shots."

Finding the KSix-One Tour 90 to be the best Tour 90 yet was Chris. "Of all the Tour 90s so far, this latest version reminded me of the ProStaff Original 6.0 85 the most. I could feel a lot more ProStaff heritage in the response and feel of this racquet. The KSix-One Tour 90 felt more maneuverable compared to the other Tour 90s and I felt like I had better control of the tip of the racquet. For some reason, previous Tour 90s always felt cumbersome compared to the ProStaff Original 85, but with this version Wilson seems to have corrected the maneuverability issue. I was also finding better access to spin with the racquet. Part of the reason was the increased racquet head speed I was able to generate. The other contributing factor seemed to come from the stringbed. I felt like I was getting more bite on the ball and better ball speed. The result was better pace, spin and court penetration on my shots than I've found with any of the other Tour 90 racquets. My favorite shot was the backhand slice. The racquet sliced through the ball like a hot knife through butter, resulting in excellent court penetration and spin. I struggled a little when hitting topspin approach shots as the mass of the racquet really pushed the ball deep. I had a little trouble getting the ball to drop inside the baseline without holding back."


The controlled response, excellent stability and impressive feel offered by the KSix-One Tour 90 made it a hit at net with most of our team. Finding the racquet more solid than the Chicago Bears' defense was Ryan "Besides the obvious disadvantage of a 90 square inch head size, I thought the racquet was unbelievable for hitting volleys. The response I got at contact made hitting my volleys on target a lot easier. Depth was another factor that was great with this racquet. It was pretty easy to get good depth on the volleys. Maneuverability was also pretty good. This is a 12+ ounce racquet that handles very well on reflex volleys. But again, the main thing that stood out to me was the solid response of the racquet at contact and the resulting accuracy." Spencer found the sweetspot of the KSix-One Tour 90 to be as sweet as pie on the volley. "When hitting volleys in the middle of the racquet I could put away shots at net. But, once again I felt very penalized for off center hits. I would say maneuverability was average."

Chris found the net to be his favorite court position with the KSix-One Tour 90. "This racquet felt incredibly stable at net. No matter the pace or weight of the shot coming at me, the racquet remained stable at contact and I was able to control my volleys very well. The head light balance made for a maneuverable feel and I felt very comfortable volleying with this racquet - so much so that the net was by far my favorite area of the court to be when wielding the KSix-One Tour 90." Jon found the racquet to be a lethal instrument at net. "I enjoyed volleying with the KSix-One Tour 90. I would have liked a larger 95-98sq in headsize at the net, but overall this racquet proved very lethal. Despite the weight, the KSix-One Tour 90 was very maneuverable at net. It's been awhile since I played with a 90 square inch headsize, and it did take a little getting used to. After a few games I felt comfortable and confident that I could put the ball anywhere I wanted."

Immediately finding the groove at net with the KSix-One Tour 90 was Granville. "Soft and crisp with excellent touch - just what I would expect from a 6.1 racquet. Maneuverability wasn't hindered with the added swingweight (as noted on the groundies) and I was immediately comfortable with the new KSix-One Tour 90 from anywhere at the net or court. I can feel the slightly smaller headsize on the really wide volleys and am considering this as a perfect compromise between my pick as the greatest racquet ever made (6.0 85) and my current favorite (6.1 95). This one offered slightly lower power than the 95, and a bit more of the 'buttery' feel of the 85."


Our team found good access to pace and spin when serving with the KSix-One Tour 90. Jon took a trip down memory lane when serving with this racquet. "Serving with the KSix-One Tour 90 was very reminiscent of my old Pro Staff Tour 90. It had a very similar feel and power level. It didn't matter if I was going big or moving the ball with spin, I couldn't find a weakness while serving with the KSix-One Tour 90." Although he may not have guns like Rafa, Ryan found the heft of the KSix-One Tour 90 more than manageable. "Serves were excellent. Pace and depth were easy to muster up, I think because of the weight of the frame. However, usually with a heavy racquet like this, I would start to feel the effects of it on my arm, in that I start to tire, and I'll start missing second serves, etc. However, that never happened with this racquet. I was able to generated great spin, and it was just an excellent racquet to serve with."

After a tepid start, Chris started to find the heat on serve with the KSix-One Tour 90. "I struggled a little early on to serve consistently with this stick. The increased weight, compared to my Pure Drive Roddick, was throwing my timing off slightly. As the playtest progressed I started to get more dialed in, but this was the shot that took the most adaptation to the racquet. Again, the racquet felt very solid and I was able to find some good spin on serves. I hit a lot of kickers with this stick, as I was a little erratic with my first serves - although they did have impressive pace. By the end of the test I was in the groove with my kick serve. I was able to consistently kick the ball out wide or jam my opponent by kicking the ball into their body." Finding some added pop to his already powerful service delivery was Granville. "This is the one stroke where I still need more time with the racquet. The added swing weight (again compared to my Hyper ProStaff 6.1) definitely affected my targeting and depth. On the second day out I was better with depth but still struggling a bit with targeting. On the upside, the added swingweight seemed to give me a bit more 'pop' on the big serves."

Spencer's serve had more kick than a plate of Kung-Pao chicken when he stepped up to the line with the KSix-One Tour 90. "Good feel and good spin when serving. I like to hit a solid kick serve and this racquet can produce just that, being able to provide good bite and kick. Once again I loved the feel, but my serve percentage was lower than usual. I think timing and lack of forgiveness had something to do with it."

Serve Returns

Our team enjoyed the solid and stable response of the KSix-One Tour 90 when returning serve. Going for some Federer like consistency on his returns was Ryan. "The return of serve was the best aspect of this racquet. I now know why Roger Federer is so consistent on his returns! This racquet is the most stable and consistent racquet I have ever used. This translates to knowing exactly where the ball is going to go when you hit. The downside is that if you hit a bad shot, the racquet isn't going to help you. I was able to block big serves with startling consistency and depth, neutralizing the biggest weapon of my opponent. And again, it was there every time. This is the best racquet I have ever returned with. Better than the previous models of Tour 90s because I never felt behind in my swing with this one, which is something that I struggled with using the nCode and Pro Staff Tour 90s." When returning serve, Chris found the racquet to plough through the ball better than a John Deere tractor through loose soil. "I found some excellent stability and feel from this racquet when returning. I was able to go after hard hit serves and generate effortless pace and depth thanks to the way this racquet ploughed through the contact zone. I was amazed at the depth, pace and accuracy I was able to generate with little effort. It never felt like the ball pushed the racquet around, and that let me use the server's pace against him."

Granville discovered that mucho racquet mass meant he was packing serious heat on his service returns. "What a difference mass makes when it comes to service returns. Defensively, just get the racquet on the ball and it will do the work for you. Get a short serve and take it early and drive it to the open corner. This added luxury of mass enabled me to approach on a service return when appropriate - it was like having an extra tool in the toolbox. With the KSix-One Tour 90, I had a sense that I came to the battle with the biggest gun and no one could take me out." Jon found that good things can come in small packages while returning with the midsize KSix-One Tour 90. "I found the racquet very well suited for returning serves. I expected it to perform well, but I was still surprised at how much control I had. Again, with a 90 square inch headsize this racquet is not for everyone. I had some trouble adjusting to this stick at first, but once I found my groove I became very aggressive with my returns with good results." Spencer found he could take a good cut at slower serves. "I had issues returning faster serves, as it was tough to get a consistent and solid stroke on them with this racquet. On the flip side, with a second or slower paced serve I could zero in and place a return with good velocity, putting my opponent on the defensive."


It helps to be an advanced player to wield a stick like the KSix-One Tour 90. While intermediate players maybe able to handle the heft, a player needs to also consistently find the sweetspot and be prepared to generate their own power from a long and fast swing style. For players that do meet the playing criteria, the KSix-One Tour 90 rewards with pinpoint precision and excellent comfort and stability. With this latest Tour 90, there's a spin friendliness we've not encountered in any of the previous versions. We also found more ball speed off the stringbed and a slightly larger feeling sweetspot. We found previous Tour 90s performed better at the lower end of the tension range (50-52 pounds), but this KFactor version provided a much livelier response at 57 pounds (2 pounds above mid tension).

Last Shots from our playtesters
Jon - "The KSix-One Tour 90 would be well suited for the 5.0+ player looking for new technology with an old school feel. This racquet is definitely not for your average player. I was supremely impressed with this stick, but I don't think I could switch to this racquet quite yet. It's still a little (OK, probably A LOT) beyond my ability. The KFactor 90 does have some advantages over its predecessors. I would definitely suggest giving this racquet a look if you are a 5.0+ looking to replace a previous Tour 90 model, or if your ready to make the jump into a Tour level racquet."

Ryan - "If I were in the market for a new racquet I would seriously consider switching to this racquet. The most stable and consistent feeling racquet I have ever used."

Granville - "This racquet should be listed as a lethal weapon. It should come with a holster. The leather grip is nice, a bit thin, as most leather is these days, compared to the old Fairways."

Spencer - "I really enjoyed the feel of this racquet. The solid feel of shots produced coming off the sweetspot was like no other. Unfortunately, there is not a whole lot of forgiveness, which I need at my level. However, if your game is good enough, this is certainly a racquet to consider and a must to at least demo."

Chris - "By far my favorite Tour 90 thus far. This version offered much more maneuverability, and I also found it much more spin friendly. I would definitely be spending a lot of extra court time with this one if I was in the market for a midsize player's racquet."

Wilson K Factor Six One Tour 90 scores

Babolat Pure Drive Cortex Standard
(Scores are determined by averaging individual play test scores)

Technical Specifications

Length27 inches69 centimeters
Head Size90 square inches581 square centimeters
Weight12.5 ounces354 grams
Balance Point12.375 inches
31 centimeters
9pts Head Light
Construction18 mm Straight Beam
CompositionnCoded High Modulus Graphite / Carbon Black
String Pattern16 Mains / 19 Crosses

Babolat RDC Ratings

Flex Rating67Range: 0-100
Swing Weight336Range: 200-400
Playtester Profiles
Chris 5.0 baseline player now using the Babolat Pure Drive Roddick. Chris uses a full-western forehand grip, has a fast swing style and hits a two-handed backhand.
Granville Granville 5.5 all-court player currently using a Wilson Hyper ProStaff 6.1. Granville is an aggressive player who uses an eastern forehand grip and goes continental on everything else, hits with a flat swing and a one-handed backhand.
Jon 4.5 baseline basher with a big kick serve currently using a Dunlop Muscle Weave 200G. Jon uses a semi-western forehand grip, has a full fast swing style and hits a two-handed backhand.
Ryan 4.5 all court player currently using a Slazenger Pro Braided Henman racquet. Ryan uses a semi-western forehand grip, a one-handed backhand and has a long swing style.
Spencer 4.5 Baseline player currently using a Prince Hybrid Hornet MP. Spencer uses a full-western forehand grip, and hits with a one-handed backhand.

Review date: February 2007. If you found this review interesting or have further questions or comments please contact us.

All content copyright 2007 Tennis Warehouse.