[USMUCL]

Finished up my second set of Pzero scrubs. I used 305/680-18 up front and 325/680-18 in the rear. -3.6 up front, -2.6 rear with neutral toe.

As with the first set, they were good for two days, then fell to crap on day 3. The difference this time, I continued to push them hard on the third day. By the end of the third 20 minute session on that third day, I had started to rip them up (pictures attached). When this setup gives way, it's the fronts that suffer most, and the car was pushing badly.

With the first set, I backed off of them on the third day, so none of the carnage you see here.

I started on 24lbs of pressure. Tested them hot after the first run and dropped them to 29-30. Went with that the rest of the day.

Overall, given the price I'm paying, I have no complaints. Two good days and a third suspect day. Going to 660 for the fronts next time, but only out of caution; the 680s up front had no obvious rubbing and no "ice mode" issues.

[NG329]

I ran that setup for a while.... exact camber and everything. I actually went back to -2.7 front and -2.1 camber in the rear. -3.7 in the front was overkill and it shortened the life of the front tires.

I run the same pressures. I used to come in at 29psi hot, but I realized that I can come in 30 or 31psi hot with no drop-off in lap times. So I stay at the higher hot pressure to get a little more life out of them.

I've since switched to the 660 aspect ratio as I find that it works a little bit better. I currently run 305/660/18 in the front and 325/660/18 in the rear and it seems that every time I go out as of late, I set new PBs. The 680 height destroyed my fender liners and it caused water to damage the headlight when it rained. A very expensive lesson.

Other than that, my experience mimics yours. I get two full days out of a set and then I'm either cording a front, or simply losing grip in the rear. I once flipped them after the first day and managed 3 full days... but that's just too much work. ....the tires are cheap enough that 2 days out of a set of scrubs is still cost effective for me.

[mikedahammer]

Where is everyone buying scrubs and how much do they cost? SC3rs run 1500 or so mount, balance, install if you go through USAA.


I am thinking about going to slicks this year but two days or 8 sessions, if that is the case, doesn't seem economical.


I should clarify I am running OEM sizes for a ZLE.

[Dabjbr]

Thanks for sharing your feedback!

I've thought about running scrubs but I also question the value proposition. So....can you share how it compares to sticky DOT tires?

For example, I run square 305/30/19 SC3R at about $1600 (before tax). With rotations, I get about 5 days (average 4 sessions per day) Let's just say $1600/20 = $80 per session.

The 3R's deliver great pace in all but wet conditions. I'm generally very happy with them. However, I do not know how they compare (pace or cost per session) when compared to scrubs.

Are you able to speak to that?

Thanks in advance!

[mikedahammer]

Originally Posted by Dabjbr

Thanks for sharing your feedback!

I've thought about running scrubs but I also question the value proposition. So....can you share how it compares to sticky DOT tires?

For example, I run square 305/30/19 SC3R at about $1600 (before tax). With rotations, I get about 5 days (average 4 sessions per day) Let's just say $1600/20 = $80 per session.

The 3R's deliver great pace in all but wet conditions. I'm generally very happy with them. However, I do not know how they compare (pace or cost per session) when compared to scrubs.

Are you able to speak to that?

Thanks in advance!

I also get about 4-5 track days depending on the track/my skill level at that track or 12-20 sessions. My fronts will generally cord before the rears are done. I did get my money's worth out of the last set of rears though.

[USMUCL]

Thanks for piping in guys; I love these discussions with folks using their cars the way I do.

NG329 -- I *think* the camber is working for me. So far, I have gotten no abnormal inside wear, including none of the inside cording I read so much about. What you see in the pics is actually the outside edges. Interesting take on using 660s in the rear; I will consider that one next.

Mike/Dab . . . I'm getting my scrubs off a guy I found on eBay. Roughly, I can get 3 full sets delivered for $1500. I have a mobile tire guy who comes to my house and does the install for $100ish each time. So, roughly $600 a set buys me two good track days and a 3rd suspect day. For me, while the rear certainly loses grip on Day 3, I feel the fronts fall off far more.

My only comparison is against new SC3s . . . the first two days, the scrubs are SIGNIFICANTLY faster than new SC3s. That third day, the spent scrubs are roughly the same speed as the SC3. Of course, the SC3s can be made to last much, much longer.

I don't have experience with the SC3Rs, but the reviews seem to be mixed. Also, I generally don't run in the rain. I'm in instructor, so when it rains, I just do the instructor part and forgo my runs. I just don't enjoy running in the rain all that much, frankly. And since I'm not getting a contract with Hendrick, the enjoyment becomes the primary goal.

[carguy55]

Ran 305/660/18 square scrubs for the 1st time at COTA. I've run other fast tires at COTA including G3R and Z214. Beat my best time by 2 seconds and there was more in it. Was able to run the full 25 min sessions without over heating them, although best lap times were or lap 2 or 3, then caught traffic. Was planning to run NASA TT2 with scrubs, which seem to have a higher chance of having pickup damage the wheel liner. Sticker tires = more pick up (OPR). Starting cold pressures were 25.

[Dabjbr]

This is great stuff! Really appreciate the conversation as well.

@Mike, that's great wear. Wish I could get down that far! I never get down that low. With rotations, I always wear the outside shoulder first and then retire the whole set. I figure, they're cycled out by then anyway.

@USMUCL, I too am an instructor with HOD. I just visited COTA for the first time last month. Did a 2:29.5 with 3R's. Randy Pobst drove my car and did a 2:28.3. It was a treat to sit passenger while he did it. I gotta post a video sometime soon! Anyway, just saying I totally get the not mindset of not tracking in the rain.

It sounds like we're spending the same amount of money per session, scrubs vs 3R's. I might have to give them a try. However, if I do, that means I need 18" wheels which then means I need coilovers too. And if I'm taking scrubs, I need to load them in the car whereas I can drive the 3R's on the street. Ugh, this shit is a slippery slope!

Finally, with some discounts, I can buy a set of 295/30/19 Toyo R's (the replacement of the RR) for roughly $6-800. They would be stretched on my 19x11 wheels but that's probably a good thing. If they perform similar to 3R's, that might be my go to tire. Just another thing for me to consider!

@Carguy55, 2 seconds faster than all the others?! That's crazy. In some ways, that makes me not want to try them for fear I'll never want to go back!

[NG329]

Originally Posted by USMUCL

NG329 -- I *think* the camber is working for me. So far, I have gotten no abnormal inside wear, including none of the inside cording I read so much about. What you see in the pics is actually the outside edges. Interesting take on using 660s in the rear; I will consider that one next.

Yeah man, I totally get it. I spent all of last year experimenting with camber changes etc.

Ultimately, what I ended up doing was run 660 front and rear, and I actually raised the front 3mm (approximately 2 turns on the front strut spanner). Now the car feels more balanced overall, it raised the roll center, and gave me the oversteer that I was seeking for the majority of corners. I'm nearly two seconds faster this season after those changes.

[wakespeak]

Originally Posted by Dabjbr

This is great stuff! Really appreciate the conversation as well.

@Mike, that's great wear. Wish I could get down that far! I never get down that low. With rotations, I always wear the outside shoulder first and then retire the whole set. I figure, they're cycled out by then anyway.

@USMUCL, I too am an instructor with HOD. I just visited COTA for the first time last month. Did a 2:29.5 with 3R's. Randy Pobst drove my car and did a 2:28.3. It was a treat to sit passenger while he did it. I gotta post a video sometime soon! Anyway, just saying I totally get the not mindset of not tracking in the rain.

It sounds like we're spending the same amount of money per session, scrubs vs 3R's. I might have to give them a try. However, if I do, that means I need 18" wheels which then means I need coilovers too. And if I'm taking scrubs, I need to load them in the car whereas I can drive the 3R's on the street. Ugh, this shit is a slippery slope!

Finally, with some discounts, I can buy a set of 295/30/19 Toyo R's (the replacement of the RR) for roughly $6-800. They would be stretched on my 19x11 wheels but that's probably a good thing. If they perform similar to 3R's, that might be my go to tire. Just another thing for me to consider!

@Carguy55, 2 seconds faster than all the others?! That's crazy. In some ways, that makes me not want to try them for fear I'll never want to go back!

First time with HOD, I was also there and had a brief discussion with Randy. Should have asked if he would drive my car also. Somehow in C group I got a clean lap and a 2:27.46 on SC3Rs. I really like how the SC3Rs handle the heat in TX but thinking about scrubs. Have been in the 2:26s but the ZL1 seems to rarely make full power in TX. 2:27s-2:28s are repeatable with these tires for me. Garmin says I should be in the 2:25s if the stars align.

[USMUCL]

The third set of P-zeros were stupid loose for reasons unknown. The only change I made was going from 680 to 660 on the FRONT; intuitively, that should have had the opposite effect. I concluded this set was just used differently when new.

That said, at the beginning of the second session, I spun the car and tapped a tire wall. I should have respected the looseness more, and I should have warmed them up more. Cosmetic damage only, and I was able to run the car, but it will be an expensive lesson.

The rear/left was cut in the mishap. After changeout, the looseness of the car went away. I'm not convinced it wasn't developing a problem before I spun (and perhaps causing the car to snap the way it did) . . . a chicken or the egg question I'll never know for sure.

[USMUCL]

I didn't give myself enough credit, it would appear. The going opinion is the damage you see in this tire was a tire failure unrelated to me slapping the wall.

That would explain why the car was so loose, and then why it finally snapped around on me during a relatively low speed turn.

I'm still not 100% sure I just didn't lose a loose car, and this damage wasn't from the wall. But, note that the separation you see here is two separate spots on the tire, and the tire wall is fully intact. Further, replacing only that tire allow me to finish the weekend, and the loose condition was gone.

$4k worth of cosmetic damage, plus the tire.