desmophile

Looking for opinion of Pirelli vs Hoosier slicks at the track. thanks, paul
Thinking about 315/18 for front and 325-345/18 rear
11" front rims, 13" rear rims
There are some good deals out there on Pirelli scrubs on e-bay.
I bought some Pirelli front 315/rear 325s.
The 315s are just slightly taller than the stock front 285 Cup 2s I have been running, and a little wider.
325s have yet to arrive but will likely be about as wide as the 335 Cup 2s, and a little taller.

Poor-sha

I'm assuming by your profile picture and mention of Cup 2 sizes you have a C7 GS or Z06. It would be helpful to post what profile size you are actually looking at. I have a C7 Z06 and like the 305/660-18 front and 315/680-18 rear which are very close to stock diameters.

I tried the 305/645-18 front and 325/660-18 rear and I do not like that rear tire. It was designed as a front tire for the Viper and as best I can tell it's just too stiff to work well on the rear. My car was prone to snap oversteer mid corner to corner exit.

I have found that the Pirelli slicks last longer than Hoosiers, wear more evenly, and are as more more grippy.

desmophile

2017 Z06/7, about 5500 miles, half at the track


Greatly appreciate the input from experience. I was thinking 305 front/315 rear, or 305 front 325 rear, or 315 front/325 rear, or even 315 front/315 rear. I don't have any experience with these tires so any input I can get is good!!!! Since these tires are relatively inexpensive, I can buy some of these two sizes and try different combos. I can buy 4 slicks used like these for the price of one Hoosier or one Cup 2 practically.

But-- last longer or more grip, either of these is encouraging. Seems reasonable to give it a try, fiddle with tire pressures and sizes, and go from there.

I appreciate your input greatly. Who knows what will work for me on my main track, Utah Motorsports Campus/AKA Miller Motorsports Park, but I can give it a try. This seems like a more cost effective solution than Cup 2's, with more performance.

I won't make my living driving fast, this is just for fun. I am as much a gear head as a speed freak.

Poor-sha

re: tire pressures. 24-25 cold, 30-31 hot.

X25

I got very similar performance from 305/660/18, 315/680/18 Pirelli DH scrubs vs. Hoosier R7 (not A7) 295/30/18, 315/30/19. Note: R7s were on wider wheels. I actually made almost identical best times with these tires during the same day (I swapped back and forth):

Both Hoosiers and Pirellis are available as scrubs, and I have a feeling that one can get even better times with Hoosiers, since larger sizes like 315/30/18, 345/35/18 are also available as scrubs.

By the way, we've had pretty bad experience with 19" scrubs, and I'd highly recommend sticking with 18" for scrubs, or buy new. The explanation from the tire seller was that noone uses 19" tires for races, and they usually come from amateurs, which means they're usually heat cycled more.

Regarding A7s: They'd likely prove to be the best performers, but they'd also degrade within a day, or two.

desmophile

Thanks for you guy's great info

desmophile

And great driving too!!!!

desmophile

OK guys, after reading what you have to say and a bunch of other info on the internet, this is what I think I will try at track days this next season.

1 keep a set of wheels with OEM Cup 2s that I have been using as a reference, and maybe early season/morning when it is cold at the track

2 I bought some Pirelli P Zero scrubs in 305/315/325-18 (4 of them for not much more than one Cup 2 costs Likely get some 18" Forgeline wheels that can clear the Brembo CCBs, thinking 11" front, 12" rear, with close to stock offset. The rear 12s would still accept a Hoosier 345 if I decided to go that route. Or should I go 13" on the rear?? Also thought if I did 11/12, I could potentially run 315F/315R. Any advice about sizing front/rear? Any advice about offset, since I could choose?

I would drive to the track on the Cup 2s and then change to slicks when it is warm enough to reasonably do so, ??70+ degrees??

Anyway, this is all for fun. I do not plan on racing or TTing. I do have a friend with a Lotus dedicated racer I would like to beat though (the Z06 can already handle the Lotus on the straights, but I need better rubber/skill if I am going to match his (on slicks) braking/cornering. And Spec Z cars on race slicks (same story) I would like to be able to corner with them so I can learn from them

X25

I think you can easily do 18x11, 18x12.5 for wide-body. Some use 18x13, but it rubs at full droop as well as at times at the track, so I don't think it'd be worth it. I don't know the exact offsets for wide-body, but I'm guessing you'd be around 40s for front, and around 55 for rear. All the vendors/manufacturers know the right offsets for C7, so they could help (just say no to 18x13 : P)

I think you could stretch a bit and even put 315s on 12.5", but I'd not want to do it on 13", since it would be 1"+ more than the recommended range.

Using scrubs is very economical. You can also use Costco for mounting (they charge $60 for 4 tires), and keep the costs very low. In my area, one Costco doesn't care what I bring them, while another one only lets new tires to be mounted, and the third one only mounts its own tires, so YMMV. After a while, I ended up moving on to a race shop I know, whose owner puts them on for $80/set.

There's one last thing to consider: tires slipping on wheels. The Pirelli scrubs are very tight, even required 95 PSI or so just to mount them, and they did not slip on the wheel, in my experience. Hoosiers, however, slipped pretty bad, and introduced quite a bit of vibration. Hoosier tires with their kevlar(?) belts are not the most balanced tires to begin with, so when you add the tire slip, it becomes grossly unbalanced. This is a big issue since it may cause premature wear on your bearings, and upsets the balance of the car, too. To avoid this, I ordered a new set of wheels (from BC Forged due to good balance of quality and price) this time, with knurled bead option. If you'll get new wheels, I'd highly recommend that you get it with this option, so your tires don't slip on your wheels.

desmophile

Super information!!
I greatly appreciate those on this forum sharing their experience and expertise.
thanks, paul

Poor-sha

Get 18x11 front and 18x12 rear. I just bought a set of Forgelines from Gerry at CW4L and he knew just what to order for offset. Those are the same wheels I just ran the 1:57.5 at VIR on.

FWIW I have no idea what tires you ordered based on what you wrote above. Diameter matters and I still recommend staying away from the 325/660-18 as a rear tire.

"I bought some Pirelli P Zero scrubs in 305/315/325-18"

desmophile

Hey thanks!!!!!
Great time at VIR

I could/should have been a little more specific, but was lazy.

got the 305s and 315 in 680 and the 325s in 705. I couldn't find any adverse comments about the 325/705 so I thought I would give them a try. I appreciate your input into this issue!!

I also appreciate your comments about the wheels, I will go with the Forgeline 18/11/12.

We will see what happens. I live in SLC and won't be back to the track until April. And may be running Michelin Pilot Super Sports even then until it gets warmer.

I appreciate your willingness to share your experience

Poor-sha

Let us know how you like those sizes and whether they rub. They are a fair but taller than stock. Stock diameters are 655/675.

desmophile

Thanks Poor-sha for all you help

Since it will be a few months before I get the P Zeros out on the track I thought I would share this info.

Currently the tires are the car are Michelin Pilot Super Sports, non run-flat, that I got to drive around town and to Pahrump as I might encounter a thunderstorm out in the desert and didn't want to just sit and wait-I don't have much faith the Cups would do well with any standing water. I like the ride and handling, and actually did a track day with them when AM temps were in the 40s and afternoon 60s. They did well on the track, but don't have the grip the Cups do, of course. Didn't rub on the track, may rub a time or two on a big bump on the freeway in Tour mode-soft shocks-but I couldn't tell which tire. Wheels are stock Z06.

Sizes for the MPSS: measured on the car
front 285-35-19 which are 680mm x 290mm
rear 335-30-20 which are 710mm x 340mm

Sizes for the Pirelli P Zero slicks I chose as they seemed close to MPSSs:
front 315-18-680, and they measure 680 x 310 unmounted
rear 325-18-705, and they measure 690 x 330 unmounted

I think the rears will clear without a problem. Hopefully the slightly taller profile will give a little more squirm/feedback before the limit. They also seem to be a rear tire for the Porsche GT3 in the Pirelli cup series, on 18x12 wheels, so they seem suited. Some good info: yeah I know it seems Porsche specific, but was the best I could find......

http://www.competentmotorsport.com/w...ta-Booklet.pdf

The front fender well look big enough to clear the slightly larger slick but we will see. (as an "experiement" I once put the rear Cups, 680 x 335 measured, on the front and fronts on the back tight turns coming out of my driveway seemed fine, went about 2 blocks and got all sorts of crazy messages about traction control problems.......yeah I know, pretty stupid)

The Hoosier 315-30-18 R7 is 650 x 320 per online specks and seem to fit per online reports.

Have you every put P Zero 315-18-xxx on the front?

If my memory doesn't fail me I will update this thread when I give this a go next season.

Nabush

Guys, If he has the CCB on his car will 18 inch wheels work ?

I'm considering buying some wheels for the track also, and even not all 18inch wheels would work with the 375mm Steel brakes...And CCB have even a bigger diameter..

Just my 2cents

X25

CCW guarantees fitment with CCBs on my 18" set, and so does a few other brands. If you have CCBs, your should always make sure you mention it though, since it might put constraints on available designs and offset range.

Lasco001

I also tested the hoosier slick a long time ago.
I threw the tire into the barrel after half a day.
For me, this is a wood mature, which does not meet my expectations

I drive Michelin and Pirelli Slick
The Pirelli is very good in price and performance.
I drive 305/645x18DM und 315/680x18DH on my car
My rims are all 10.5x18 and 12.5x18



Cölestin

mcoomer

Not to hijack your thread, but I'm considering this same tire setup once the SC2's are used up. Figure a little extra sidewall will help fill up the wheel wells without having to lower the car. Have you had any trouble with these sizes while driving the car?

Thanks,
Mike

desmophile

Hey Mike,
I have had good service from these tires/sizes. They don't rub on the street or the track. The car seems to like them, no funny traction control or other messages on the dash. They are good on the track with reasonable feedback when they are approaching limits. They don't have the ultimate corner grip of the Cup 2s, but that is what you would expect. On the street they are good as well, noticeably more comfortable than the cups. Drove them to Spring Mountain from SLC with comfort, low noise and stability. I have had my car set to track settings per manual and just drive it on the street like that, which other than the trip to Pahrump, I don't do a lot of. I am pleased with this set up. I carry a tire patch kit and inflator since they are non run-flat. Out here in the mountain west, the likelihood of getting a flat and limping 50 miles to a town with a replacement tire in stock and ability to mount it is sketchy at best.

They do fill up the wheel wells more than cups.


paul

desmophile

Here are some pictures of those tires on the car. Not great pictures but it was raining outside, sorry