When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Took a closer look at the dunlops today. The center tread is totally washed away. These tires are done. After only 2 days. Bummer. They were good while they lasted. Gonna have my used front cup2s that have some life left in them mounted up front and keep the rear dunlops which are still good on
Bizarre - it looks like huge overinflation. I know you did not do that, so probably their cords are optimised for more barrel-shaped profile of the tire, which makes no sense for these cars.
Fits what I've been saying all along about the Dunlops. Good on the road, good on track up to 8/10ths, will disintegrate fairly quickly when pushed beyond that. I had all kinds of chunking when I tried them in the Cayman and 997. Not an option for serious track guys.
I wonder if Dunlop designed this tire with different rubber as Michelin? Maybe the center tread blocks have stickier rubber, and the inner/outer blocks are different?
My buddy has 991 gt3 that came from the factory with dunlops. Unfortunately, center tread wore out the same exact way and he was on bone stock alignment and ran lower pressures than I did.
Joe -
I will be running the GT3 for the first time at Laguna on Monday with PCA. The car came stock with the Dunlops so my only basis of comparison for a stock setup will be the Spyder with the Eagle F1's. I will be using a pyrometer to checks temps and adjust pressures accordingly. Will target the 34-36 pressures you suggested. Can't wait to get on the track after a summer absence.
Bizarre - it looks like huge overinflation. I know you did not do that, so probably their cords are optimised for more barrel-shaped profile of the tire, which makes no sense for these cars.
Yup. Fernando's gt3 came with these tires and the same thing happened to him, except he was on bone stock alignment and ran much lower pressures than I did (30/32).
Remember this test in Germany had the same outcome in term of center wear as well: https://rennlist.com/forums/991-gt3-...-michelin.html
Originally Posted by Manifold
Fits what I've been saying all along about the Dunlops. Good on the road, good on track up to 8/10ths, will disintegrate fairly quickly when pushed beyond that. I had all kinds of chunking when I tried them in the Cayman and 997. Not an option for serious track guys.
Yeah, I loved the tires until I saw what happened to the front center tread. They were great while they lasted, which wasn't long at all. :-(
Originally Posted by MileHigh911
I wonder if Dunlop designed this tire with different rubber as Michelin? Maybe the center tread blocks have stickier rubber, and the inner/outer blocks are different?
My understanding is that the Dunlop rubber is uniform all of the way across, which could be the problem. The Michelin center rubber may be stiffer.
Originally Posted by MileHigh911
Joe,
Have you asked any of your Geo guys if they have any thoughts?
My shop thought it was over inflation as well, but based on what other have seen and also the magazine review, I think that this is just what the tires do. I did love the tires before they wore out though....
Am I the only one that feels like the car oversteers a bit? Maybe it's a Trofeo R thing? I'm switching to MPSC2, but I am going to soften the rear sway bar to see if that helps. I am getting a lot of oversteer on corner entry and putting down power on exit. Much moreso than with the C2S I had.
Just want to provide one more data point with regard to the Dunlops. I'm on my second set and my wear pattern on the fronts look exactly like Orthojoes. My fronts were half worn after only one of Joe's private track day marathons. I've been trying to run 29 front 31 rear hot.
Am I the only one that feels like the car oversteers a bit? Maybe it's a Trofeo R thing? I'm switching to MPSC2, but I am going to soften the rear sway bar to see if that helps. I am getting a lot of oversteer on corner entry and putting down power on exit. Much moreso than with the C2S I had.
Nope, not just you. I was fighting oversteer with trofeoR as well. Californians in general haven't had success with trofeoR. Lol. I think you'll have success once you are back to cup2 again, Mike.
Originally Posted by ggt3guy
Just want to provide one more data point with regard to the Dunlops. I'm on my second set and my wear pattern on the fronts look exactly like Orthojoes. My fronts were half worn after only one of Joe's private track day marathons. I've been trying to run 29 front 31 rear hot.
Some people binge-watch Breaking Bad or Game of Thrones. I just binge-read Orthojoe's Track Build Journal. Holy smokes. Now I can eat, shower, and emerge from the bunker. Just in time for Thanksgiving.
Nice work, Joe. Thanks for sharing such valuable info. Now we need this for the GT4...
Some people binge-watch Breaking Bad or Game of Thrones. I just binge-read Orthojoe's Track Build Journal. Holy smokes. Now I can eat, shower, and emerge from the bunker. Just in time for Thanksgiving.
Nice work, Joe. Thanks for sharing such valuable info. Now we need this for the GT4...
Lol. Thanks! GT4 antics will start in March.
Happy thanksgiving!
Same thing happened on the front Dunlops on my GT4. 3 AutoX events and they are basically done down the middle with a decent amount left on the shoulder.
I ran Laguna on Monday with PCA. Got meatballed once for sound. Really had to coast up the hill to not blow sound. After 4 sessions the front right (Dunlops) center block was completely rounded on the outside edge. In addition, no matter what changes I made between sessions to lower that pressure it always came back higher than the inside and outside. Hot tire pressures were in the 34 front 36 rear range with slight variations above and below. Car has stock alignment and both sway bars are in the middle setting.
To say the least the GT3 on track was amazing. Yeah the Spyder is fun but the GT3 is just incredible. Really sharp turn-in. No under or oversteer but I am only at 7/10's. Rolling on the throttle at turn exit gives you all the HP you miss with the Spyder. Definitely felt good trail braking on Turn 2 which may have been a necessity given how much speed (120+) you can carry down the front straight. Corkscrew was fantastic. A little tire chirp on top and then a little wiggle if early on the throttle at the bottom.
I did not use sport plus or the paddles. Every time you get on it and the exhaust opens up is really a rush but you already that. Just an amazing car.
FWIW, I've tracked the 991 GT3 back to back with the Cayman R (on NT01) on a couple of tracks, and the GT3 simply blows the R away, not just in pace but also handling and overall intensity. The passive suspension of the R feels stiff enough on the road and gives the car an enjoyable go-kart feel, yet it feels too soft on track, resulting in the car rolling much more than the GT3 and not being as planted and precise overall. So, I enjoy the GT3 more on track, and the R more on the road (manual transmission is part of that). The GT3 can be more fun on the road, but that requires unrealistically hyperlegal speeds. Still putting break-in miles on our new GT4, and haven't it tracked it yet, but it may turn out to provide the best balance in terms of both performance and fun on both road and track among all of the cars I've driven.
Another data point for Sport Cup2 outer tread block wear. I'm liking the theory discussed earlier that the outer tread blocks will wear sooner than center and inner just due to the varying tread compounds across the tire's surface. Granted, my car is a 991S and not a GT3, so suspension is different (PDCC, stock camber settings, no RWS), but overall chassis and weight distribution is basically the same.
Never ran the car on the stock PZeros.
First tires were AD08Rs, which wore the rears before the fronts (10 track days).
Second tires were Sport Cup2s, which also wore the rears before fronts (6 track days).
Third tires are current, replacement set of Sport Cup2s, which are actually wearing the L front much more than the R front or rears after two track days at Lime Rock (all right-hand turns except one). Maybe because the first set of Sport Cup 2s saw a mix of tracks (Watkins Glen, VIR and NJMP, in addition to Lime Rock), they wore more evenly?
In any case, wear pattern on outer tread blocks of that L front tire is pretty strange. The tread surface scallops in from outer edge to inner edge of the outer tread blocks, wearing more towards the inner edge and finally ending in a step-up lip or ridge on the innermost edge of the outer tread blocks, running circumferentially around the tire. Also, each outer tread block is "feathered," so that the wear is more toward the rear of each individual outer tread block, and becomes less as you move forward on that tread block. Input from the track section of the forum suggests issues with overinflation, not enough camber, and surface graining from sliding.
Last edited by paradocs98; 11-27-2015 at 05:26 PM.
11-18-2015, 02:33 AM
