Z/28: Let's Talk Tires!

[JusticePete]

Originally Posted by johnr265

OK, after getting a more aggressive alignment, I realize I was trying to compensate for tire rollover (caused by not enough negative camber) by increasing the tire pressure too high. Now, with more camber, I am finding that I am closer to your range. I plan to try 33 front, 31 rear next time and run -3.2F, -2.1R

Can you post your caster and toe settings?

[johnr265]

Front:
Camber -2.9
Castor 5.8
Toe -.05 (toe out per side)

Rear:
Camber -1.8
Toe .10 (toe in per side)

Indeed, did use moreno camber plates. Plates are at about 45 degrees and in max position. For the front, this was the max castor for the given camber. As you increase camber, you lose castor so if I go up a bit on camber, I will lose a bit of castor. This setup was REALLY good. The small tweaks I am thinking of are based on tire wear and probably not critical. I did need to use lower control arms and toe arms in the rear (BMR) in order to get more negative camber in the rear. I only did one day on this setup and won't get a chance to do more for a couple months but I am dying to get back out.

I did notice a very slight rub on one turn at Summit Point, last turn onto straight which is high speed and high compression. Couldn't find culprit but suspect might go away with a touch less castor.

[BaylorCamaro]

Originally Posted by brt3

Yokohama AD08R -- I really like these and have even used them at COTA in cold/wet weather...

I too run these tires (305 all four corners) on my ZL1. I really like them, I feel they have similar grip levels of the Pilot Super Sports but they seem to manage heat better IMO.

[JUSTIFIED]

Having the newly released Continental Extreme Contact Sport tires installed today. Did some research and they appear to be great tires (Conti used the Michelin PSS as the bench mark and partnered w/ several professional drivers during development). They do run a bit narrow (tread width = 10.9"), but only weigh 27 lbs. I will only be using them on the street.

If interested here is an in depth article about them http://www.motoiq.com/MagazineArticl...act-Sport.aspx

[Raven87]

Originally Posted by JUSTIFIED

Having the newly released Continental Extreme Contact Sport tires installed today. Did some research and they appear to be great tires (Conti used the Michelin PSS as the bench mark and partnered w/ several professional drivers during development). They do run a bit narrow (tread width = 10.9"), but only weigh 27 lbs. I will only be using them on the street.

If interested here is an in depth article about them http://www.motoiq.com/MagazineArticl...act-Sport.aspx

Stock size? Or bigger? I look forward to hearing what you think once you get them on the car.

Thanks.

[JUSTIFIED]

Originally Posted by Raven87

Stock size? Or bigger? I look forward to hearing what you think once you get them on the car.

Thanks.

Sorry...should've include size info. I went w/ stock size at each corner. They are significantly narrower than the Bridgestone RE-11As, but I'll take it with weight reduction of 8 lbs/tire. W/ rotational force applied that's equal to ~ 24 lbs/tire (note: Tire Track reports a weight of 27 lbs. The article I posted seem to contradict that. Seat of pants test....they feel substantially lighter than the Bridgestones (35 lbs) ).

The car feels/handles much like it did w/ the Trofeos (street use only... I know the track is a different story), except not nearly as much tramming. They did get loose under hard acceleration while coming out of a u turn, but that may be due to new rubber. I was in PTM5 and easily brought it under control. Steering is much lighter and overall feels a lot more responsive. I'll never put heavier tires on her again.

Here are a few pics....

1) Comparison w/ Bridgestones, 2) Front, 3) Rear 4) Driver side view

[D2M]

Mann, those RE-11s look in great shape. I wish I was closer, I could use 2.

[JUSTIFIED]

Originally Posted by D2M

Mann, those RE-11s look in great shape. I wish I was closer, I could use 2.

Should seriously consider the new Contis....

[JUSTIFIED]

Couple of pics from a different angle. Front and rear Pics above make the tire look smaller than it appears in person.

Edit: If someone can fix (i.e. rotate) the images it'd be much appreciated. I tried, but could not do so. Thanks!

[D2M]

Originally Posted by JUSTIFIED

Should seriously consider the new Contis....

For a strictly street tire the Coni is a great choice. I try to keep the treadwear around or under 200 so its a no go for me.

[Raven87]

Those Contis look really good on there - thanks for the feedback!

And, here are your pics rotated.

[JUSTIFIED]

Originally Posted by Raven87

Those Contis look really good on there - thanks for the feedback!

And, here are your pics rotated.

Thanks for fixing my pics! Also, the tires look better in person.

[kramard]

I'm tire shopping!

Can't decide between the following...

• 295 R888R all four corners. It's stretching by .5" in the rear but I've spoken to two shops and they say it'll be a-ok. $1,185 for four... other option is to do 295 upfront and 305 in rear at ~$1,368
• 305 98Y Sport Cup 2 $1,472 - not sure what the difference is between the 102Y but has the same treadwear rating. Very intrigued by this option
• 305 RE-71R $1438 - after reading this review (http://www.prima-racing.com/bridgest...king-part-two/) it seems like the RE-71R compares closely with the NT01. I believe the R888 and R888R are related to the NT01 - if I can get similar lap times with a little more street friendly manners I'd seriously consider the RE-71R
• 305 RE-11 $1306 - D2M has me sold on these as well.
• Others that I've looked at, though not as seriously... V720 (probably a bad choice since its auto x specific but gosh the price is right), RS-4?

My goals are:

• Acceptable daily driver manners e.g., noise is ok but car does travel to from track under its own power and I can drive as far as 300 miles one way occasionally. Not worried about a stiffer ride quality. Prefer less tramming then the Trofeos
• Needs to be ok in rain; Trofeo ok... that is. Id prefer if the tire handle highway speeds in rain acceptably given I'm not driving dumb (I had no problems with worn Trofeos in moderate rain at 65mph but I was attentive)
• Ideally 6 - 8 track days + 7kish street miles would be amazing but based on my experience with my Conti DWs and Trofeos I feel like I'm dreaming. Longevity is important meaning I'd pay a little more for a tire that lasted longer and provided the same lap time. I presume all the tires above will provide a similar lap time though.
• As much as I tell myself lap time isn't important... it is. I was sad when I couldn't keep up with a C63 AMG on Trofeo Rs when I was on my Contis.

Anyone have some thoughts? Appreciate any advice in advance! The 295 R888R are cheaper then the remaining options while the others will provide better street manners. I would not be shaving the R888Rs down and let them progressively wear (is that a bad idea?)


Thanks all.

[D2M]

For the goals you have stated above I would rate the tires listed in this order.

1. RE-71. I think this tire will have a bit more grip then the RE-11 but at the cost of some street manners.
2. RE-11. Great all around tire, Jack of all trades, master at none.
3. Sport Cup 2. Proven great tire, should be able to get ~7k out of these, rain performance will be bad however.
4. R888R. Best grip level but probably hell in the rain and longevity.

Check out the Yokohama AD08R, this is also a great proven tire. Kumho V720? Hankook RS-4?

These are just my opinions, everything is a compromise, I don't think you will be disappointed with any of these options, however they will all turn to slime under heavy track use under the Z/28 heft. I personally am dying to try the R888R myself.