Last spring, it was time for a new set of tires, so I decided to try a set of Falken Azenis RT-615s in 205/50-15. For the two years prior, I had been running 195/50-15 Goodyear Eagle F1 GS-D3s on my Miata. Now that I have some experience with more than one set of tires, I can give a meaningful comparison and review of them.

My Miata’s Setup
I’m going to be talking about how each tire feels, but that doesn’t mean much without knowing exactly what has been done to the rest of my car. So, here is what I’ve done to my 1999 Mazda Miata: Flying Miata Springs (the older models); KYG AGX 4-way adjustable shocks; Flying Miata sway bars, set at the stiffest setting front and rear; Kosei K1-TS wheels, 15×7 inches (the older, 11 pound model). I also have a racing seat (a rebadge of a Cobra Monaco), and a 6-point, 2 inch Willans Harness. The racing seat and harness help immensely with feeling connected with the car, and really make the subtle nuances of each tire stand out. My car has no ABS, so threshold braking feel is also important.

My alignment settings have also shifted somewhat over the last few years. When my Goodyears were on the car, I aimed to run 1.2 degrees front camber, 2.2 degrees rear camber, 1/16 inch toe in, and the maximum caster allowed with those specs (it usually worked out to around 5-6 degrees). The place I went before wasn’t that competent, and couldn’t always meet those specs, but they were usually close (and I never really noticed much of a difference anyways). Currently, I’m running 1.5 degrees camber in the front, 2.2 degrees rear camber, 1/16 inch toe in, and 9 degrees of caster.

It should also be noted that different sized tires on the same width wheel will experience different amounts of side-wall flex. A wider tire on the same sized wheel will always have more sidewall flex, which has a very large affect on turn-in and ride comfort. A 7-inch rim is perfect for a 195mm tire (which is what the Goodyears are), but at the upper limit for a 205mm tire (Azenis). (I would be hesitant to put a 215mm tire on a 7 inch rim.) So, I cannot directly compare all aspects of each tires’ performance, but this review will give a good comparison of the overall setups.

Turn-In
Goodyear Eagle F1 GS-D3
Turn-in with the Goodyears is nothing short of incredible. The front of the car changes direction effortlessly and immediately, with absolutely no slop, delay, or feelings of resistance of uncooperativeness. The sidewalls feel like they are made of steel, and there is no discernable sidewall flex to note. To use the common cliché, it literally feels like the car is “riding on rails.”

Falken Azenis RT-615
Turn-in with the Azenis’ is much sloppier overall than with the Goodyears. They have a weird feel to them, where you can feel the contact patch grabbing and darting around quickly and precisely, like the Goodyears, but where there is a definite disconnect between the contact patch and the car. The car always felt one step behind the contact patch, so quick inputs and evasive maneuvers had to be “timed” more than just initiated. Don’t get me wrong, turn-in was still very good and acceptable, just not nearly as good as with the Goodyears.

I have a feeling that this phenomenon is probably a result of the tires’ size as much as anything else. The wider Azenis may be experiencing more sidewall flex because it is on a comparatively smaller width rim, as noted above. Also note that I am running more caster with the Azenis, and am noticing a worse turn-in. Usually (in most cars), increasing caster will aid turn-in “bite.” It is hard to say whether or not the Goodyears’ advantage would be even greater if I had also been running 9 degrees of caster when they were on the car.

Preference
I prefer the Goodyears significantly for Turn-in.

Grip
Goodyear Eagle F1 GS-D3
The Goodyears exhibited amazing grip, particularly for only a 195mm tire. For comparison, I was able to directly trail a brand new, Porsche 911 Turbo through the Bowl at NHIS using these tires. Grip was high enough on the street to make it downright reckless to flirt with the limits of lateral grip.

Most importantly, grip was extremely consistent. It didn’t matter if it was very cold or very hot - grip always felt at the same level. In the dead of winter in New England, with temperatures well below freezing, grip trailed off noticeably, but that is the case with any tire. Only once, when it was in the high 80s at NHIS, did I notice the Goodyears get a little greasy. And this was only in one spot on the track: Turn 3, the hairpin. The tires felt fine elsewhere, so it is conceivable that there could have been some nastiness deposited on that part of the track.

Falken Azenis RT-615
When I put the Azenis on at the end of April, I was completely blown away by their level of grip. There was tons more grip available for braking and turning than I had ever experienced with the Goodyears, so much more that I was unable to push them to the limit on the street out of fear for my own safety. That level of grip on the street is beyond reckless, it is dangerous.

At Watkins Glen, I was extremely impressed with the level of grip. Maximum grip was much higher than the Goodyears everywhere. In Turn 7, the right hand sweeper right after the bus stop, I was actually able to gain on some of the fully race-prepped BMWs in my run group - and they were outfitted with R-compounds.

My first time with them at NHIS, however, I was extremely unimpressed with the level of grip. Not only did the Azenis have less grip and feel more greasy than they did one month earlier at Watkins Glen, but they actually felt less grippy than I had remembered the Goodyears to be at that same track. I ended up spinning but recovering going out of Turn 2 because I was expecting a much higher level of grip than the Azenis afforded (granted this was my own fault for overdriving my car, but, in my defense, I was not expecting the Azenis to underperform as they did).

In subsequent track days, the Azenis performed MUCH better. I suspect that low tire pressure was to blame for my initial upset at NHIS. Tires’ grip also tends to drop off after the initial few uses, so I may well have experienced this initial high traction at Watkins Glen. Once tire pressure issues were sorted out, grip was VERY high with Azenis. Not quite as high as I remembered at Watkins Glen in the Spring, but very close.

Preference
Neutral. Interestly, after my initial events at Watkins Glen, both tires seem to have pretty comparable levels of grip. My entrance and exit speeds with both sets were similar enough that I can’t put one tire as being clearly superior to the other. I give a toss-up on grip.

Tire Communication
Goodyear Eagle F1 GS-D3
The Goodyears communicated every bump and imperfection in the road right back through the steering wheel and chassis. Smaller imperfections were fine, but larger bumps should definitely be described as harsh. I prefer this to a softer ride, though, as I want to know exactly what is going on between my tire and the pavement.

Breakaway was easy to predict, identify, and control. I never had any issues recovering from oversteer. To be fair, my driving style does not involve much oversteer, on or off the track, so my experience for either tire on this front is admittedly limited.

Falken Azenis RT-615
Tire communication with the Azenis compares to the Goodyears much like turn-in. I could sense every bump and imperfection in the road, but they felt dampened by the time they reached me. It was not a bad dampening, as I still received all of the information that I needed. It was just less raw.

Breakaway was also easy to predict, identify, and control, though I would rate the Goodyears higher in this respect. The goodyears just felt easier to control and manage breakaway and oversteer.

Preference
Neutral. I don’t dislike the dampened, comfort feel of the Azenis, but I prefer the raw feeling of the Goodyears. Ultimately, communication was acceptable enough in both tires that other areas of performance far more critical.

Ride Quality
Goodyear Eagle F1 GS-D3
The rock-solid sidewall of the Goodyears comes at price: ride quality. The stiff sidewall that instantly transfers steering inputs to the contact patch also transfers every bump and imperfection in the road. As I mentioned above, I don’t dislike this harshness, as it can be fun and satisfying to have such a raw, pure ride. Others may disagree with me.

I did not notice how noisy the tires are, as Miatas tend to be fairly noisy to begin with. There is not a lot of sound dampening, on the chassis, virtually none on the soft top, and you are so low and close to the ground that you hear and feel everything. Comparatively, the Goodyears did not seem and louder or quieter than the Azenis.

Falken Azenis RT-615
The opposite of the Goodyears. The softer sidewall damped bumps and imperfections significantly, and made things more plush on the road. Don’t expect the plushness of your grandmother’s Cadillac, but you won’t feel like someone welded the shocks in place.

Preference
Neutral. I like the raw feeling of the Goodyears, but don’t dislike the more comfortable, plush feeling of the Azenis. Most importantly, the Azenis did not give up any responsiveness/communication for the softer ride.

Hot and Cold Performance
Goodyear Eagle F1 GS-D3
The Goodyears are amazing. Hot and cold performance is IDENTICAL, over the course of any reasonable temperatures to which you would normally subject a maximum performance summer tire. I noticed a little bit of greasiness as noted above one day at NHIS when it was almost 90 degrees, but even then it was only in one specific area of the course. With this one exception, performance in the first lap of a 20-30 minute session with the SCDA was identical to performance in the last lap. I did notice grip fall significantly in the cold New England winters we are cursed with, but that is normal more the fault of physics than the Goodyears.

Falken Azenis RT-615
I had initially attributed the Azenis poor performance at NHIS to a higher ambient temperature, but I think that has since been ruled out. I’ve driven in other events during hot days, and have not experienced the same low level of performance.

I did not notice any difference in the performance of the Azenis over the course of a track session. The Azenis performed consistently when cold or when warmed up. This is not to be scoffed at.

The Azenis RT-215, which was replaced by the RT-615, was notoriously bad at dealing with heat. They would reportedly become very greasy after a few aggressive laps at the track. The RT-615 has reportedly addressed this issue significantly, and I would agree with these reports. It should be noted that my experience with this tire has been in a lighter weight car. There have been reports of heat difficulties with the RT-615s in heavier cars, though I do not have any personal experience or knowledge myself.

Preference
Neutral. Initially, I thought that the Goodyears won in terms of hot and cold performance, but I now think that was due to tire pressure. Both tires were consistent and did not exhibit fade when pushed hard for a long track session.

Optimum Tire Pressure
Goodyear Eagle F1 GS-D3
Optimum performance with the Goodyears was found with a cold tire pressure of 31 psi, which would rise to around 36 psi hot. I found this setting to give good grip, sidewall pressure, and responsiveness, both on and off the track, and in any condition I encountered.

Falken Azenis RT-615
For initial street driving, I settled on 33 psi cold with the Falkens. I found this helped some of the sidewall flex I was experiencing, without noticeably affecting grip or ride comfort and responsiveness. I used this pressure at Watkins Glen, and the tire performed extremely well as noted above. My first time at NHIS, I started at this pressure, with terrible results. I gradually reduced tire pressure over the remaining sessions, and found a lot more grip and less greasiness at 31 psi hot. I didn’t take a cold psi reading, as the tires were already warm, but that probably puts them in the 27 psi cold range.

I later tried putting in more pressure, and found optimal pressure to be 40 psi hot. Any pressure beyond this and the tires would become greasy.

Rain Performance
Goodyear Eagle F1 GS-D3
Rain performance with the Goodyears is amazing. Some have said that it is the best rain tire on the market. I can at least say that it performs extremely well. Driving it on the street, I noticed no difference between dry and wet conditions, even under more aggressive driving. I have driven these in torrential rainstorms on the track, and grip was reduced significantly, as expected. I haven’t had much experience with other tires under similar conditions, so I can’t give a fair appraisal of their performance. I was able to keep pace with much more powerful cars than my Miata, and tires lose more cornering grip than acceleration grip in the wet. So, either the tires or my driving (or both) were on the ball.

Falken Azenis RT-615
On the street in the rain that I have experienced, the Azenis have performed fine. I did not notice a difference between wet and dry performance, but admittedly have not pushed them very hard on the street. On the track, I ran a day at NHIS with torrential downpours. Grip was very impressive, and I was able to pace Miatas with RA-1 racing tires and some minor drivetrain upgrades.

The older, Azenis RT-215 were notoriously poor wet weather performers. Without having driven the RT-215s, I would say that the RT-615 does not suffer the same wet weather difficulties.

Preference
Both tires performed fine in the rain, though the nod would have to go to the Goodyears.

Breakaway Feel and Controllability
Goodyear Eagle F1 GS-D3
Breakaway responsiveness with the Goodyears was extremely good. It was very easy to predict when breakaway would occur and when the tires were actually slipping. They were also extremely easy to regain and retain control of when slipping. Braking responsiveness was equally good, with good feedback as to when the tires had locked up.

Falken Azenis RT-615
Breakaway responsiveness was good, though not quite as good as with the Goodyears. I found oversteer slightly harder to control, and the car seemed more prone to fishtail upon recovery. These difference are very slight, however, and should definitely not be a deal maker or breaker for either tire. Most of my experience with slippage was at NHIS, where temperatures were warm and the tires seemed to be performing their worst. I do not know if the Azenis would experience the same characteristics in a colder setting, as I was more behaved at Watkins Glen.

Preference
The Goodyear wins, but only slightly. It felt a little more controllable when slipping, but only marginally.

Tire Life
Goodyear Eagle F1 GS-D3
I used the Goodyears hard for 2 solid season, and most of my track experience with them was during the second season. They performed amazing throughout their life, and I did not notice any appreciable deterioration in any of its performance areas. Presumably grip dropped off, as fresh rubber is always grippier. But, the loss was not significant enough that I noticed. Tire wear was completely even on all 4 tires.

Falken Azenis RT-615
These survived 1 season with about 10 track days with room to spare. I am getting noticeably more wear on the inside of these tires at all 4 corners – a phenomenon that I did not experience with the Goodyears. For that reason, I will be replacing them at the start of the next season. This is morely likely due excessive camber for these tires on my car being driven as I drive it, so I don’t fault the Azenis for this wear. Interesting, the camber settings are virtually the same as with the Goodyears, though I don’t push the Azenis quite as hard as I pushed the Goodyears.

Recommendation
If your goal is to have maximum grip on the street for on-ramping, I would recommend the Azenis over the Goodyears. The cold grip of the Azenis is unbelievable, and definitely the tire’s strongest point.

If your goal is ride comfort, the Azenis would win again. But if ride comfort is your primary criteria, you should not be buying maximum performance tires.

For every other criteria, the Goodyears win hands down. The Azenis have a higher peak grip under ideal, colder conditions, but equal or less grip under warmer conditions. The grip of the Goodyears is consistently very high, and consistency is far more important than a maximum peak grip. When going into any corner or braking, on the track or on the street, I want to know, not have to guess, what my grip will be.

Overall responsive and feel is far superior on the Goodyears then on the Azenis. The car felt directly connected to the contact patch and the road with the Goodyears. With the Azenis, it felt like there was some “play” between the chassis and the contact patch. Quick lane changes, and tossability was much higher with the Goodyears. Once again, much of this may be due to the wider width of the Azenis. In any event, my ultimate recommendation goes to the Goodyears.