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[Richbot]

For a street tire, who cares if they grip as well as PSS at the limit, so long as they aren't squealy squeaky messes that turn square when they're parked for more than a couple days. The Kumho performance tires I've used have had grip for the money, but you don't get what you don't pay for and for me that has meant a lot of other compromises. Maybe they've turned that around

[617E90M3]

Its too bad they don't do 295's in 18's or I would give them a shot

[redpriest]

I had a pretty positive experience with these tires at the track. After my Maxxis RC-1s corded on the 2nd session of the first day of what was going to be a 2-day track weekend at Auto Club Speedway and Chuckwalla, I had little choice but to switch to my street tires. I had driven 500 miles to get here and I wasn't going to let the weekend go to waste!

I'd driven these tires on the street for a good 8000 miles prior to tracking them, so they had a decent amount of tread left. I run -3.0 deg camber so running cheap replaceable tires is a must for me - I got tired of throwing away full treadway PSS simply because of the shoulder wear.

My Maxxis RC-1s (R-compound) were on end of life and I was struggling to break into the 1:54s - my best time was in the morning with a 1:54.5, and this is with a square 275/18-35 setup.

Enter the PS91s on 245/19-35 and 265/19-35. I wasn't expecting much, but I was really shocked with a 1:54.054 best lap, and consistent low 1:54 laps afterwards. I didn't want to push my luck given that I didn't know how heat resistant the tires were, so I ran hot lap - cold lap alternating.

1:54.054 is only 1.1ish seconds off my best lap ever, a 1:52.9 lap on Nitto NT01s.

Next day at Chuckwalla, I beat my old personal lap of 2:08.14 (set on RE-71R) with a 2:07.05 - all of this is driver mod, I am under no illusions that the RS91 is better than RE-71R.

I found these tires to be very controllable and predictable - very confidence inspiring - I spent some time drifting around the track at ACS and was able to initiate and catch the slides easily.

It's probably a good idea to not punish them with hot lap after hot lap, grip will probably fall off pretty quickly if you do this. After about 6 20-min sessions, these tires are now at the wear bar on the inner half of both my front tires. I did not rotate these tires, and since both ACS and Chuckwalla are CCW, this was punishing on the passenger side tire, but visual inspection shows that they held up pretty well considering.

ACS:

Chuckwalla CCW:

[aus]

Great to see some REAL data on these tires!
What width 19" wheels do you run? I'm running 255/35 and 285/30-19 on theses tires for the street and they've been great. It's nice to know they'll do ok on track too.

[Nugget]

Originally Posted by aus

Great to see some REAL data on these tires!
What width 19" wheels do you run? I'm running 255/35 and 285/30-19 on theses tires for the street and they've been great. It's nice to know they'll do ok on track too.

That's what I'm running as well and very happy with them so far.
Nice to know they will stand up to a couple of laps even though I wasn't planning to track this car.

[Dreamer99]

These Kumho tires sound promising. I'm looking for a street tire with the stiffest sidewalls for the two or three track sessions I do per year. How would you rank them in comparison to the PSS and S04 (and others?)?

[redpriest]

Originally Posted by aus

Great to see some REAL data on these tires!
What width 19" wheels do you run? I'm running 255/35 and 285/30-19 on theses tires for the street and they've been great. It's nice to know they'll do ok on track too.

These were on the standard ZCP style 359 wheel, so:

(2) Front Wheels - 19x9" ET31 (25.4 LBS, 31mm offset) - BMW Part # 36-11-2-284-055
(2) Rear Wheels - 19x10" ET25 (26.6 LBS, 25mm offset) - BMW Pat # 36-11-2-284-060

@Dreamer99 - with regards to PSS/S04 - I haven't run PSS on this car on the track in forever (I did do a pouring rain track day on PSS at Sonoma, but traction that day was so bad, so couldn't really give you an unbiased answer. Haven't run S04 at all.

My biggest memory of PSS was them screaming all over the place in every turn I made; PS91 is quieter but will still let you know when you're at the limit with a squeal. They are very controllable at the limit.

They don't come with a lot of tread, so I would be concerned about pounding them repeatedly at track days. I think brand new, they would be good for 3 track days at most if you were rotating, and if you were doing 4 20-min sessions per day.

[dparm]

Not sure what your camera setup is, but I recommend running a cheap lapel mic out to the rear bumper. No wind noise and sounds way cooler.

[redpriest]

Originally Posted by dparm

Not sure what your camera setup is, but I recommend running a cheap lapel mic out to the rear bumper. No wind noise and sounds way cooler.

Oh, I have an external mic if you look at my other vids. The extension wire was broken this time out though, so no good sound

[Richbot]

Would be interested in a pic of the fronts and rears when you get a chance - for science

[aus]

repriest should consider the 255/35-19 and 285/30-19 on his next set, though I do rub a little on the passenger side rear when the wheel compresses.

[redpriest]

Originally Posted by Richbot

Would be interested in a pic of the fronts and rears when you get a chance - for science

Fronts after 5-6 sessions:

[redpriest]

Originally Posted by Richbot

Would be interested in a pic of the fronts and rears when you get a chance - for science

Rears:

[redpriest]

I drifted on these tires, for what it's worth, on several laps. :

[redpriest]

Originally Posted by aus

repriest should consider the 255/35-19 and 285/30-19 on his next set, though I do rub a little on the passenger side rear when the wheel compresses.

Hmmm. For these tires I'm going for as cheap as possible, so not sure if the incremental cost is worth it.

[aus]

That's pretty impressive wear for track work and the drift work!

[speedracerlo]

I got these for a few of my cars as replacement tires. Pirelli P Zero are the worst ever and so many cars come with it from factory.
Where did everyone get the 7.8/32 tread depth info from? Mine say 9.8/32 tread depth from Tirerack

[M3SWEETNESS]

Originally Posted by speedracerlo

I got these for a few of my cars as replacement tires. Pirelli P Zero are the worst ever and so many cars come with it from factory.
Where did everyone get the 7.8/32 tread depth info from? Mine say 9.8/32 tread depth from Tirerack

Yeah I was thinking the same thing when looking at the specs... I just ordered these to replace my Falken fk453s. Going with 275/35/19 and 295/30/19, same size as my Falkens. I'll make sure to check the tread when they come in and post initial thought.

[M3SWEETNESS]

So got the tire in and installing them as I type this. Measured them and they are right at 10/32 depending on the sizes... I did 275/35/19 and 295/30/19, the tool I had measures at "mm" but going off of every 1.6mm is equal to 2/32 of thread depth we can figure the actual depth. Here are the 275s


The 295s... Measured a little higher but I imagine it's about the same as the 275s.


So given the measurements and the math behind the conversion they are both right at or a bit higher than 10/32 thread depth.

[M3SWEETNESS]

Follow up on these tires... as far as daily driving I've done about 300 miles on them. So far I like the ride and the traction, road noise is non existent. One thing I will say is these run a bit taller than usual. The fronts are rubbing the fender liner where the other 35 series tires would not. So just bought another pair 275/30/19s for the front to remedy this. The 35's series will now be my back up rear set on my stock rims for autox.

[chicog]

@M3SWEETNESS is it cause youre lowered that the 35 in the front rub ? im planning to go 265/35/19 in the front and wanna make sure i wont rub with this tires and the 295 in the back its ok?

[aus]

If you're lowered, you're better off running 255/35 and 285/30. I get rubbing in the back with a 19x10, et 22 wheel but I'm lowered a fair amount.
.