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Pirelli Slicks

1,281
3
Tulsa, OK
Anybody have any experience with Pirelli slicks? I picked up a barely used set of 4 305/645/18s for pretty cheap and I'm just curious how they compare to other R-compounds. I'm coming from a set of 275/35/18 Hoosier R6s.
 

ArizonaBOSS

Because racecar.
Moderator
8,545
2,376
Arizona, USA
They're a lot closer to 285 width than "305". You might consider running a spacer up front just to be safe.

I had a set of used ones and IMO they were as good as a sticker set of R6s. If yours are new, they're going to be phenomenal.

Target HOT pressures at 30 PSI, typically you'll be starting "cold" around 24-25 PSI.
 
1,281
3
Tulsa, OK
Thanks for the info. I did figure they would run a little skinnier than advertised. I have some small spacers I can use if necessary. I've been using "used" R6s for my last few events and the grip is so addicting. Looking forward to the possibility of these being even stickier 8)

My next question was going to be about pressure so thanks for touching on that as well.
 
I just mounted up a set of sticker Contis and they say spring rate xx 30 psi @ 800lbs which looks to mean target a 3200 lb car so I was thinking of continuing to target 32-34 hot in our 3600ish lb cars.
 

ArizonaBOSS

Because racecar.
Moderator
8,545
2,376
Arizona, USA
cloud9 said:
I just mounted up a set of sticker Contis and they say spring rate xx 30 psi @ 800lbs which looks to mean target a 3200 lb car so I was thinking of continuing to target 32-34 hot in our 3600ish lb cars.

Sounds good for sticker contis...if they start going away towards the end of the session, drop the cold pressure 1-2 PSI. I was told 39 hot on those but they did not like that at all. But mine were used.
 
1,281
3
Tulsa, OK
cloud9 said:
I just mounted up a set of sticker Contis and they say spring rate xx 30 psi @ 800lbs which looks to mean target a 3200 lb car so I was thinking of continuing to target 32-34 hot in our 3600ish lb cars.

I will most likely shoot for that and adjust accordingly.
 

captdistraction

GrumpyRacer
1,782
1,322
Phoenix, Az
cloud9 said:
I just mounted up a set of sticker Contis and they say spring rate xx 30 psi @ 800lbs which looks to mean target a 3200 lb car so I was thinking of continuing to target 32-34 hot in our 3600ish lb cars.

The conti's I ran seemed to love 35 hot, and I was able to get almost 20 sessions out of a set before starting to show cords.

I'm hoping the 305 pirelli's are narrow. Either have to sell my 18x9.5 wheels or try to stretch them on.
 
Wow, you guys are running the Conti's low :eek: I have been going with 39 in the front and 37-38 in the rear. I get good wear with that pressure but may try a little lower next time out and see how they handle. When I first tried them I corded two sets quickly at 34-35.
 
3,677
3,555
YellowBoss said:
Wow, you guys are running the Conti's low :eek: I have been going with 39 in the front and 37-38 in the rear. I get good wear with that pressure but may try a little lower next time out and see how they handle. When I first tried them I corded two sets quickly at 34-35.

that's hot...correct?

Tell you what, run about 29-31 in the front, 25-27 in the rear (cold) and see what happens on those Contis.
 
blacksheep-1 said:
that's hot...correct?

Yep, it was Rich Martin that told me to run them up higher. He said 40 PSI was good hot. I start with 27-28 rear and 28-29 in the front and a difference of .5 (cold) on one side depending on the track, we have two left and two right turn tracks down here.
 
3,677
3,555
cloud9 said:
What do you recommend for HOT pressures on our heavier 3600 lb cars?

Look at my last post 29-31 in front 25-27 in the rear, opposite of what yellow boss is running. Stay under 42 hot if you can, def 45.
This becomes a whole science that begins with cold pressures at a specific ambient temp, you need to keep specific notes on all of those parameters. Honestly, I'm not at much liberty here, I can push you in the right direction but then you're on your own..sorry.
 
blacksheep-1 said:
Look at my last post 29-31 in front 25-27 in the rear, opposite of what yellow boss is running. Stay under 42 hot if you can, def 45.
This becomes a whole science that begins with cold pressures at a specific ambient temp, you need to keep specific notes on all of those parameters. Honestly, I'm not at much liberty here, I can push you in the right direction but then you're on your own..sorry.
I only gain 1lb more in the fronts hot than rears. Been starting 26 front 27 rear and landing about 33-34 hot. The stickers on my brand new Contis show spring rate at 30 psi hot. I typically run DOT tires like Nittos or R6s at 40-41 hot but was always told to run slicks vonsiderably lower. In fact the Corvette guys run them around 28 hot but they're lighter at around 3100 lbs. I guess I could give higher pressures a shot and see what happens.
 
3,677
3,555
Don't compare different brand tires or street tires to slicks, it really muddys up the situation. Try my suggestion and run a small rear bar and see what happens, that's about all you can do. Remember over 40-42 hot is death, bad things start to happen. Always start with known cold temps and then check them hot, don't go hot first because you can get into trouble and end up too high.
Let me re-touch on that, it appears that you are not using the rear of the car to it's fullest, ,like I said in another post, the Roush guys were lifting the front tires at Mid Ohio and running a ton of squat. Maybe loosen up the rear shocks, lower spring rate or (probably the best route, try loosening up (smaller) rear bar. (or forget everything I said and do just the opposite to the front) it depends on how well the car sticks.
FWIW an old stock car guy told me that the biggest mistake people make is that if the car feels "loose" they tighten up the rear, then the front "pushes" so they tighten up the front, pretty soon the car is so tight that it's eating tires, and doesn't go through the corners. Sometimes it pays dividends to do the opposite. If the rear is loose, then loosen the front and try to get the car neutral. remember slow cars always handle, so it's only going to get so good. It's a complicated game.
Plz let me know.
 
blacksheep-1 said:
Look at my last post 29-31 in front 25-27 in the rear, opposite of what yellow boss is running. Stay under 42 hot if you can, def 45.
This becomes a whole science that begins with cold pressures at a specific ambient temp, you need to keep specific notes on all of those parameters. Honestly, I'm not at much liberty here, I can push you in the right direction but then you're on your own..sorry.

I'm not opposite of this, I run the rears a little softer. I am pretty close to what you are saying but also like you said it depends on many factors. What I like to do is set the cold pressure the day before with the tires inside the garage, then load the car. Next day at the track as soon as I unload I check again before the sun comes out, mainly to check for a tire going soft.

The biggest problem I've been having is getting the fronts too hot around mid-day when it starts to get very hot here. The morning run (advanced is normally out first thing in the morning) and second run they don't get all the way to temp and pressure. By mid-afternoon and later I keep taking pressure out and still set off my alarm which is set at 41. This is when I start to see some center wear, the car still sticks well but the last two times out I wore the center faster.

On second thought the biggest problem is being driver, owner and crew all in one! Sometimes I am just too tired to jump out and adjust pressure after a run.

Good point on the sway bar, I just put in an 18MM bar after installing the coil overs and it digs in hard coming out of the corners. I thought just getting the coil overs was nice until I matched them to the rear bar.
 
3,677
3,555
Check your PM

also http://www.longacreracing.com/catalog/item.asp?id=1319&catid=7


Try to find the optimum tire pressure for your car and then work backwards to find a cold pressure. Notes..notes..notes
 

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