The new Falken Azenis RT660+ vs. the RT660 | 200tw tire test

Things move quickly in the high-performance tire world courtesy of constant innovations in materials, design and manufacturing techniques. Getting an optimal combination that hits all of the possible design goals takes a huge investment of both time and money. And if the tread pattern is also new, you’ll need a bevy of shiny new molds–another large expense.

Given that the …

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It would be interesting to see consistency calculated in the lap time tables to see if that's changed any, or just if the driver seems to be getting more dialed in over the day.

Lap times are not the issue with the Falken, its the center rub falling off after 3 laps. If that didn't happen, they are an improvement over the old. They burned me twice with poor quality, it will take more data to convince me to try them again. 

theruleslawyer said:

It would be interesting to see consistency calculated in the lap time tables to see if that's changed any, or just if the driver seems to be getting more dialed in over the day.

That's the whole point of bracketing the test.  Same tires are run at the beginning and end.  Gives a read on any changes related to driver or surface change. 

For this test, the final set of runs on the RE71RS are about .15 quicker on both single lap best and average (not shown, but I've done the math).  So a case could be made that a small portion of the 4 tenths gain from RT660 to RT660+ was due to that.   But single tenths are also easily within the noise of this type of testing.

Further, we are privvy to some other unpublished real world 3rd party comparison testing of these two tires from a reliable source.  And those results are similar to ours, both the objective and subjective portions.  So our confidence is high on this one.

pinchvalve (Forum Supporter) said:

Lap times are not the issue with the Falken, its the center rub falling off after 3 laps. If that didn't happen, they are an improvement over the old. They burned me twice with poor quality, it will take more data to convince me to try them again. 

Did you do a mild initial heat cycle (or pay to have it done) before hammering on them?

I've seen this happen with RT660's that were bolted on as stickers and pushed hard.

Either way, one of the results of the change was more even pressure distribution across the face, so that should help the cause.

Andy: Did the 660+ develop a tread splice failure? Looks like something in the photo.

Also, funny typo "Flaken" in the photo caption!

jwasilko said:

Andy: Did the 660+ develop a tread splice failure? Looks like something in the photo.

Also, funny typo "Flaken" in the photo caption!

Good eye!

Actually, I must have those labeled backwards -- it was the outgoing tire that did that.  Pretty ironic.

I'll have the guys get the piece fixed up.  This one got rammed through quickly.

....

Ninja edit now complete.

PS: Failure is too strong a word.  It's cosmetic only and typically wears away in short order.

If memory serves me well, the RT660s got faster after losing 2/32nds of treadwear. Would be interested to see a test of these versus RE71Rs at a similar tread depth - I recall the RE71RS being a bit squirmy at full tread.

Andy Hollis said:

theruleslawyer said:

It would be interesting to see consistency calculated in the lap time tables to see if that's changed any, or just if the driver seems to be getting more dialed in over the day.

That's the whole point of bracketing the test.  Same tires are run at the beginning and end.  Gives a read on any changes related to driver or surface change. 

For this test, the final set of runs on the RE71RS are about .15 quicker on both single lap best and average (not shown, but I've done the math).  So a case could be made that a small portion of the 4 tenths gain from RT660 to RT660+ was due to that.   But single tenths are also easily within the noise of this type of testing.

Further, we are privvy to some other unpublished real world 3rd party comparison testing of these two tires from a reliable source.  And those results are similar to ours, both the objective and subjective portions.  So our confidence is high on this one.

Yah, I understand the bracketing. However my catalyst pumps out a consistency stat. It would show how stable the lap times are. Sometimes you talk about tires falling off, or maybe that one tire is easier to drive than another. That sort of data could probably be quantified by looking at how variable lap times are. I was just looking at all the lap times and trying to figure it out in my head.

In reply to sibanez :

RT660 long-term study right here ==> https://grassrootsmotorsports.com/articles/how-optimize-tires-quicker-laps-and-longer-life/

As for the RE71RS, here's a test with both a full tread and 5/32 version -- big difference ==> https://grassrootsmotorsports.com/articles/hoosier-trackattack-pro-tire-test/

And finally, we have another long-term test result we'll be sharing soon, along with lots of other 200tw tips & tricks.

In reply to Andy Hollis :

Serious ninja editing!

pinchvalve (Forum Supporter) said:

Lap times are not the issue with the Falken, its the center rub falling off after 3 laps. If that didn't happen, they are an improvement over the old. They burned me twice with poor quality, it will take more data to convince me to try them again. 

My RT660 experience has been less than stellar as well.  I have a set of 205/50's on an 8" wheel on my turbo miata, they never felt "good" always low grip and slidey.  And during a test and tune last year (several events and road miles into their life) I made the mistake of hot lapping the car and the center rib started coming apart.

Then a month later a TTN I was using the men's room when I overheard a couple of other racers complaining about their tires delaminating.  I said "ah, talking about the RT 660 I bet".  They weren't surprised I'd guessed right, it was a junk tire and had earned it's reputation.

In reply to Andy Hollis :

Thanks, missed that. I liked the way the RT660s drove, especially after wearing a bit. Sounds like the changes fixed some of the unpredictability you'd feel that made consistent times hard. 

FWIW, I have run through two sets of RT660s on my Miata: 19 autocross events and about 4100 miles total on the first set and probably a little less time on the second. (Blame driving the GTI.) Details on the first set here. 

Why did I replace the first set? Grip seemed down.

What’d I find? No center wearing at all with tread measuring 6/32 all around. 

I did rotate this set once or twice. 

I did heat cycle both sets, though. I followed Andy’s advice of running them on the highway plus some cloverleafs. Then the tires were allowed to sit. 

I need to measure the current/second set, but my eye says they’re wearing fine. Probably time to fit fresh tires for 2025 as the second set has been on the car since early 2023.

Looks like the RT-660+ posted more consistent lap times.  Looking at the first run RE-71RS and the outgoing RT-660, they both got slower with slowest lap times higher than the RT-660+ slowest lap time.

I am likely going to get these.  I ran the regular 660s for 4 years and like them for what they are.  Vitour in their short goofy 15" sizes is not going to work for me.

I run a 245/40 on a 9" front and a 205/50 on a 8" in the back on a turbo fwd ax car.  Should I consider a 225/45 on the 9 for the extra slight weight reduction and potentially sharpen the respose a little?

malibuguy said:

I am likely going to get these.  I ran the regular 660s for 4 years and like them for what they are.  Vitour in their short goofy 15" sizes is not going to work for me.

 

I run a 245/40 on a 9" front and a 205/50 on a 8" in the back on a turbo fwd ax car.  Should I consider a 225/45 on the 9 for the extra slight weight reduction and potentially sharpen the respose a little?

Vitour will be coming out with normal height 15" sizes later in the year.  225/45-15 and 245/40-15 are on the slate, as well as 275/35-15

As for 245 vs 225 on 9's in the RT660+, we have not directly compared those sizes on this tire model.  But on other similar tires, we have seen that they deliver similar lap times albeit in slightly different ways.  The bigger tire is a little better in the middle of the corner, while the 225 is better everywhere else.  It isn't so much the weight as the shape of the contact patch.  Neither will be the wrong answer.

Andy, you're doing the Lord's work here, thank you. Also good to hear Vitour will be making some taller 15's. I'd love a set for the Exocet, but shortening that car's gearing is not the way to go.

I just received my 660+ in 265/35/R18 on some new wheels. I ran the 615+ in a 245/40/R18 last year for my first TNIA and full season of autox and was super impressed as a beginner. Took a risk on the new version to save some $$$ as it was a big offseason with upgrades. Hoping to get at least 1 TNIA, 2 Time Trials, and 15 autox events out of them, might be alot but fingers crossed!

any plans for an autocross test? I do SCCA TT but i also autocross and am interested if the rt660+ is quicker or has improved heat characteristics vs rt660 at autox.

derekmcmillen said:

I just received my 660+ in 265/35/R18 on some new wheels. I ran the 615+ in a 245/40/R18 last year for my first TNIA and full season of autox and was super impressed as a beginner. Took a risk on the new version to save some $$$ as it was a big offseason with upgrades. Hoping to get at least 1 TNIA, 2 Time Trials, and 15 autox events out of them, might be alot but fingers crossed!

Be sure to heat cycle them for maximum longevity.