Azenis RT 660 missing strips of tread

[Gearhead1]

After a lapping day, the front Falken Azenis RT660’s on my 2013 BRZ have circumferential strips of tread missing. The rear tires are fine.
The LF tire has a nasty groove right down the middle. At the worst spots the groove is 2/32" deep. The LF also has a very faint groove near the inside edge of the tread.
The RF only has a groove (3 of them, actually) near the inside edge of the tread, but it is a bit nastier than the inside edge groove on the LF. See pictures.
I reached out to technical@falkentire.com and received this email response from Christopher Guth, QA Supervisor with Sumitomo Rubber North America Inc.:
“…there is some lateral scrub happening on the tire shoulder, also evidenced by the greater wear on the shoulder compared to the middle of the tread. I agree that this does not look like a cut, but it is from lateral side forces “pushing” the shoulder tread inward. I can’t say that it is a defect since the tread construction is the same across the whole tread face (i.e. there are no construction joints that run circumferentially in that area with the 3 lines). Typically, we have seen in racing environments that this is due to camber and/or inflation pressure settings.”
I responded and asked if lateral scrub at the shoulder of the tire could account for a missing strip of rubber in the center of the tread and if the wear indicated pressures too low and too much negative camber. Guth’s email response:
“Any type of shoulder wear could indicate inadequate air pressure and/or incorrect camber. If both shoulders are wearing faster than the center then that would indicate too low of pressure. With too low of pressure (especially in a race setting) you would also have a “fold over” effect leading to the lines on the tread, including the line at the center of the tread. While I can look at the tire and read what is happening to it, unfortunately, we do not have data to provide on the optimum vehicle settings to avoid this type of wear. That would have to be more of a trial and error experiment for your particular vehicle. For that type of information I would direct you to forums and such other resources.
As for the wear itself, I would add that as long as you are maintaining proper inflation pressures this is not a safety concern, but more of a cosmetic issue.”
I’m not a tire expert and I may not fully understand Guth’s explanation. Has anyone else seen this kind of wear (I call them missing strips of rubber, Guth called them “lines on the tread”)? If so, what was the cause and what was the fix? Any suggestions for me?

[NoHaveMSG]

I have seen other tires look like that but not the RT660. What tire pressure where you running?

[Gearhead1]

Originally Posted by NoHaveMSG

I have seen other tires look like that but not the RT660. What tire pressure where you running?

My car is an automatic (=slow!) and to get every advantage in acceleration and speed, I tried size 205/40R16. With that tiny size, the load rating is significantly reduced, so 32 psi (cold) is the minimum pressure I use, and that on the drive to the track. Starting pressure for first session at the track is 34 front, 32 rear. Hot pressures coming off the track are 38-40 front and 36-38 rear.

[NoHaveMSG]

Originally Posted by Gearhead1

My car is an automatic (=slow!) and to get every advantage in acceleration and speed, I tried size 205/40R16. With that tiny size, the load rating is significantly reduced, so 32 psi (cold) is the minimum pressure I use, and that on the drive to the track. Starting pressure for first session at the track is 34 front, 32 rear. Hot pressures coming off the track are 38-40 front and 36-38 rear.

That is strange you are getting that wear on the inside like that. What is your front camber?

On 245/40/17 I was usually running around 35psi hot with that tire though your different specs may change things a bit. I’d say temp probe them next time and see if you are getting abnormally hot in those area’s. I just don’t know what’s causing it and their explication doesn’t match what I see. To me, your pressures seem too high and usually unless you are running well over -3 degrees of front camber these cars tend to tear up the outsides off the fronts.

Here’s a pic of my RT’s after 4 track days. Wear is on outside edge even with -3.5 front camber.

[Gearhead1]

Thanks for posting a pic of your tires and your camber specs.
I run a lot of camber: -4 1/8 LF and -3 3/4 RF and zero toe. I've been willing to tolerate wear on the inside edge (much of which probably occurs on the 200 miles round trip street driving to and from the track) in order to lessen the wear on the outside edge. From what Guth with Sumitomo Rubber said, I wondered if high negative camber was causing the problem, but I still don't see how that caused the groove down the center of the LF tread. And Guth's statement that "Any type of shoulder wear could indicate inadequate air pressure and/or incorrect camber" caught my attention. I'm pretty sure shoulder wear is a fact of life with street cars like ours.

[strat61caster]

Yes I’ve seen this before on other rt660s, stories all over autocross forums and Facebook and Reddit. Glad you got the feedback from their QA that the solution is to just power through it and try not to overdrive em. They do like higher pressures is something I’ve heard pretty consistently.

[Breezio]

Originally Posted by strat61caster

Yes I’ve seen this before on other rt660s, stories all over autocross forums and Facebook and Reddit. Glad you got the feedback from their QA that the solution is to just power through it and try not to overdrive em. They do like higher pressures is something I’ve heard pretty consistently.

All the stories I've previously seen about the 660s is about a slice across the tire where the seam between tread sections has come apart slightly. Happened with my own set. To which they tell you it'll be fine and keep driving.

This is the first I've seen with a grove with the thread.

[NoHaveMSG]

Originally Posted by Gearhead1

Thanks for posting a pic of your tires and your camber specs.

I run a lot of camber: -4 1/8 LF and -3 3/4 RF and zero toe. I've been willing to tolerate wear on the inside edge (much of which probably occurs on the 200 miles round trip street driving to and from the track) in order to lessen the wear on the outside edge. From what Guth with Sumitomo Rubber said, I wondered if high negative camber was causing the problem, but I still don't see how that caused the groove down the center of the LF tread. And Guth's statement that "Any type of shoulder wear could indicate inadequate air pressure and/or incorrect camber" caught my attention. I'm pretty sure shoulder wear is a fact of life with street cars like ours.

So I have noticed some heavier inside wear on tracks that have several long loaded corners at higher negative camber settings. I was digging through some tire pictures and I do have one where my left front was as worn on the inside as it was on the outside. I just attributed it to high static camber putting it up on the inside edge under load. Never had the wear you show though. Though I settled on 35psi hot, I had run anywhere from 33-37psi with the 660's.

[strat61caster]

Originally Posted by Breezio

All the stories I've previously seen about the 660s is about a slice across the tire where the seam between tread sections has come apart slightly. Happened with my own set. To which they tell you it'll be fine and keep driving.

This is the first I've seen with a grove with the thread.

Tread, no threads in tires, it's not a blanket.

I only spent about 5 minutes searching, here's some similar issues, plus the two or three sets I've seen do this in person that didn't get posted online.

https://grassrootsmotorsports.com/fo.../175273/page1/

https://www.reddit.com/r/Autocross/c...es_camber_and/

https://www.reddit.com/r/Autocross/c...rt660_tearing/

[Gearhead1]

Originally Posted by NoHaveMSG

So I have noticed some heavier inside wear on tracks that have several long loaded corners at higher negative camber settings. I was digging through some tire pictures and I do have one where my left front was as worn on the inside as it was on the outside. I just attributed it to high static camber putting it up on the inside edge under load. Never had the wear you show though. Though I settled on 35psi hot, I had run anywhere from 33-37psi with the 660's.

I may try less camber and keep pressure at 40 on my next track day (could be a while) and I'll update with the results. When I do go out, the rears will be rotated to the front and vice versa, so it will be easy to see if the grooving, if any.
Interestingly, this problem occurred on my second track day with these tires. The first time out, I put about 80 track miles on and the tires were fine. On that first outing, I had a stiffer front sway bar and a touch of front toe out--other settings were the same as the second outing. Ambient temps were low 90's for both outings. Second track day was about 85 track miles.

NoHaveMSG, the pic of your tire tread after 4 track days looks remarkably uniform and good to me. I am curious if you know about how many track miles that was.

Thanks to everyone for your comments.

[NoHaveMSG]

Originally Posted by Gearhead1

NoHaveMSG, the pic of your tire tread after 4 track days looks remarkably uniform and good to me. I am curious if you know about how many track miles that was.

Around 400, +/-25.

[Gearhead1]

Originally Posted by NoHaveMSG

Around 400, +/-25.

Thanks!

[Breezio]

Originally Posted by strat61caster

Tread, no threads in tires, it's not a blanket.

I only spent about 5 minutes searching, here's some similar issues, plus the two or three sets I've seen do this in person that didn't get posted online.

https://grassrootsmotorsports.com/fo.../175273/page1/

https://www.reddit.com/r/Autocross/c...es_camber_and/

https://www.reddit.com/r/Autocross/c...rt660_tearing/

You really didn't read or understand my post did you?
I wrote tread, not thread.
And I said this is the first I've seen, not that this issue doesn't happen. Just so happens I have seen dozens of reports (my own included) about the tread splice issue.

[Ultramaroon]

Originally Posted by Breezio

You really didn't read or understand my post did you?
I wrote tread, not thread.
And I said this is the first I've seen, not that this issue doesn't happen. Just so happens I have seen dozens of reports (my own included) about the tread splice issue.

Originally Posted by Breezio

All the stories I've previously seen about the 660s is about a slice across the tire where the seam between tread sections has come apart slightly. Happened with my own set. To which they tell you it'll be fine and keep driving.

This is the first I've seen with a grove with the thread.

Spelchek is ur frendd

I suggest proofreading before posting snarky reply.