New Dunlop Z2 Star Spec

[Asterisked Accolade]

http://www.tirerack.com/tires/tests/...68&cid=Q33880&

Tires tested:
Dunlop Direzza Sport Z1 Star Spec (Extreme Performance Summer)
Dunlop Direzza ZII (Extreme Performance Summer)


Vehicles used:
2012 BMW F30 328i Sedan
In the Extreme Performance Summer tire category, the Dunlop Direzza Sport Z1 Star Spec has a strong following among driving enthusiasts, autocrossers and track-day drivers. And it's for good reason — this tire has a reputation for delivering impressive dry traction and well-balanced capability in all directions of the friction circle — cornering, acceleration and braking. All this packed in a tire that you really can drive to and from the track.
When rumblings of its replacement began to surface in the summer of 2012, fans of the Direzza Sport Z1 Star Spec debated the pros and cons of any change while they waited to see if Dunlop could find performance improvements without losing the good in an already great tire. Dunlop's development target was simple if not easy: improve dry traction and handling without sacrificing any of the wet or wear characteristics of the Direzza Sport Z1 Star Spec.
Pavement-eye view of the Direzza ZII cornering hard.

What Dunlop came up with is simply called the Direzza ZII. Short and straight to the point, the ZII looks the part of a dry track performer that begs to be driven hard, with a more solid tread pattern than the Z1 Star Spec. Dunlop is bringing the Direzza ZII to North America in early 2013, and when it arrives we'll do a comprehensive road and track test to find out how it compares with other tires in the category. In the meantime Dunlop brought us a set of production-spec tires to try out before we closed our test track for the season. We also pulled a set of Z1 Star Specs off the shelf to benchmark the ZII and get an idea of how well Dunlop hit their mark.

As the autumn afternoon temperatures hovered around 60° F we set cold tire pressures to our standard tire test setting of 35psi front/rear, and scuffed in both sets of tires to wear off any mold release. We then got started by running some baseline laps on the Direzza Sport Z1 Star Spec. True to the tire's performance in past tests, this tire goes about its business with minimal fanfare and rewards a smooth driving style.
In many instances the balance of the car with Direzza Sport Z1 Star Spec tires has just enough rotation at the rear to help the car glide around the corner, requiring minimal steering input to manage the few degrees of drift. Aggressive or early throttle input powering away from the corner can create a little power-on oversteer, however. Steering behavior is relatively good as the tire drives down to the apex, but you have to lead it just a little bit or risk falling behind when multiple steering inputs are required. Maneuvers such as the multiple side-to-side inputs of our five-cone slalom, as well as the right-left-right of our increasing radius S-turns, reveals the one potential weakness of the Z1 Star Spec, where the rear can get out of phase with the front, resulting in some transitional oversteer if not driven smoothly. Earlier and smaller steering inputs help tame it, as does keeping some weight on the rear tires. Avoid big speed adjustments mid-slalom or risk the tail wagging the dog.
Direzza ZII's quick steering response had us driving over apex cones.

With the Direzza Sport Z1 Star Spec tires still warm from their exercise, we hopped into another of our test cars shod with the Direzza ZII tires and set off to see what they have. From the first turn it was apparent this isn't the same tire. The Direzza ZII displayed noticeably more direct and positive steering response from the front tires. So much in fact, that we ran over a few apex cones in the first half of the first lap due to how the car was now diving to the apex with real authority. Lateral stability through the slalom was noticeably better, with a considerable improvement in composure at the rear of the car. Acceleration traction was noticeably better too, as this tire let us use much more of the torque of our turbo'd BMW 3 series test car, allowing for harder and earlier throttle application that results in forward progress, not sideways motion as might happen with the Z1 Star Spec. It's hard to say that the Direzza ZII has significantly more steady-state lateral grip than the Z1 Star Spec, but it does use what it has much more effectively. This pumps up driver confidence in rapid transitions and high speed maneuvers, resulting in higher velocity and lower lap times.


We then turned on the track's sprinkler system to make a quick assessment of wet performance. Once the track was thoroughly soaked we had time in the schedule for just a few laps on each tire. Here the Direzza ZII again showed a noticeable advantage over the Direzza Sport Z1 Star Spec. The steady-state overall grip level was similar, but the ZII was much more predictable at the limit, with noticeably better communication of where the limit is, along with faster recovery once any slide began. It was just plain easier to go faster with the Direzza ZII.
Dry
Avg. Lap Wet
Avg. Lap Dunlop Direzza Sport Z1 Star Spec 29.56 35.00 Dunlop Direzza ZII 29.08 33.84 Time Difference -0.48 -1.16

[gmookher]

Ok. Sold for daily driver duty.

[GTB/ZR-1]

Strong wet-weather performance over the Z1s--which are pretty good in the wet.

I wonder how they compare to the R-S3s in the dry.

They are a pretty heavy tire, relatively speaking 1-2 lbs corner makes a difference on our cars where hundredths sometimes matter.

[Aznsky]

Originally Posted by fredk

I e-mailed Luke at Tire Rack...he got right back to me and said they would do it. It was an issue with someone that may have not known their policy about Competition tires. Hopefully he'll pass the word. We did call the rep and plead with him and he said "no". Hopefully they did not ship my stuff unmounted....

I run 295's on 9" rims on the front of my Cobra.

Please keep us updated on what you receive, if they're not willing to fit a 235 on the stock wheel then that's a concern.

Did you go 235/40/17?

THanks!

[fredk]

I did call them directly after e-mailing with Luke to make sure they did not ship them separately. I spoke with someone in the wholesale dept and he also told me they would not mount them. I pointed out that Tire Rack was the title sponsor of our series....

I'm hoping Luke can talk some sense into someone. These wheels were made for this car and this class with this size or wider tires.

Yes, I have the 235/40-17's ordered. I may got with the 245's if they won't mount the 235's, 245's will fit fine and are cheaper.

Hopefully we'll have it resolved Monday.

[Aznsky]

wait how would 245's fit better since they're a wider tire? Are they having an issue with the sidewall height then? or is that just a typo?

[Asterisked Accolade]

Comparison video.
http://www.tirerack.com/tires/tests/...68&cid=Q33880&

[JesseE]

Originally Posted by Kamran

New to FRS and ran into this thread. My experience with Z1's weren't so good as you can see from the pix (from trackdys in Pacific Northwest).

Z1's may be ok for autoX since you don't get them finger burning hot or for too long a time (4 or 5 runs, at 60 seconds per run). Doing a couple of full days of trackdays may be different.

These were not shaved, not that you should have to, in order to void serious chuncking. Problem solved with Nitto NT1's.

Just to clarify, this happened running my 3200# Audi Quattro, and not my FRS.

Curious to see reports on trackday tires FRS drivers using...

Audi's suck so bad even the tire's couldn't wait to get off the car...

[Dezoris]

I don't like not knowing colder weather performance.

I preferred the Z1 over the RS3 just for the more usable all around performance as a street tire.

Did the Z2 go more for a higher heat range and less performance in the cold like RS3?

Also please post back about 245 on OEM wheel.

[jeebus]

i wish these tires weren't so dang heavy.

[Aznsky]

I've heard weight is actually a good thing when it comes to tires because it typically represents stronger carcass reinforcement which would help in less flex of the tire and sidewall under hard cornering.

Just things I've heard from fellow racer friends.

[Jedi1]

a 245 will fit on the 7" rim, but I would not recommend it. The break away characteristics of the tire will be GREATLY exagerated by the buldge that fitting a 245 to that rim will cause. In short, been there, thought it would be great. More tire has to mean more grip, right? Not in this case! The tire became spongy at the limit and when it let go, it did so in a violent way. This was with the Z1 and then the RS2 on a CSP Miata a few years back. I wouldn't do it. It's your car though and if you aren't looking for peak performance, but rather want to fill the wheel wells, it will fit on the rim.

[ayau]

Why are people trying to fit 245 on 7" rims in the first place? These aren't R comps. Are people trying to fit the widest tire for SCCA RTR class?

[Jedi1]

Some are. I kind of hope it's the ones I'll be running against at National events, lol.