I8ABMR

I recently got a set of Michelin Pilot Super Sports in the oem sizes ( 225/255 ). This weekend on the way home from dinner I ran into an ISF. I asked the owner if he was upsized and he was running the 245/285 combo that I initially wanted. The car looked great !! I called discount tire and told them to oder me a set of the 245/285 S04 Pole Position . I am doing a track day soon and was wondering how the 285 rear tire feels at 10/10ths. As well know the 9" wheel should only have max 275 mounted. My concern is how the tire wall feels when cornering really hard. If there sidewall flex? Does the car still feel sharp and responsive. My concern is going with the wider sizes and then the car feel sloppy . I know we are talking 10 mm so its probably negligible but just wanted to see if we have track day member who are running the 285 rear on the stock wheels rather than the more common 275

Thanks for your help guys

lobuxracer

iTrader: (2)

Are you primarily concerned about how it feels or about how it performs? It will probably feel OK. It will also probably be disappointing if you put a watch on it and measure the performance.

When you spend money, you surely have to be concerned about placebo effect. It is massive in the aftermarket.

I8ABMR

In the end what I am primarily after is more corner exit grip and more stability in the extremely hard transitions and S curves. I have solved the understeer issue with the rear sway bar. WIth worn old RE050As the car would oversteer on corner exit and the exit speed would be lower, and my speed down the main straight would suffer. Allso at wild horse pass there is a very long high speed right hand curve thats taken at probably close to 70 mph followed by a 60 foot straight followed by a hard left ( 90 deg). During this transition the suspension would be really loaded up then as the car straightens out I apply the brakes. I as am braking and setting up for the hard right the car is usually fighting for grip in the transition. The only other option is to come in at lower speed but.... nobody wants to do that. My concern is the sidewall flexing and inducing some oversteer with the 285 ( probably splitting hairs) . I am pretty sure the increase in the size of the contact patch will give me the corner exit speed I want , but was looking for some feedback or personal experience.

suprasupra

It sounds like you will have two setups a track set and a street set , why don't you just forget the street tires and move to R compounds for your track set along with upgraded race pads and motul.
why do you want two sets of street tires ?
If you are looking to go fast R compounds are the way to go at the track.

Bigcloud

I agree with the above poster, for me it's Rcomps, slicks or bust. Then again I bought a dedicated race car. No need to beat up on a DD.

I run Hoosier R6's
Nitto NT01's
Toyo R888's

I8ABMR

Not 2 sets of tires guys. I was planning on dropping the Michelin PSS for the wider S04s. My car has to do it all so I am looking for a great compromise. My issue is a 285/30/19 safe on the track with a 19x9 wheel.

The ISF is the kind of car that can be driven to the track, kick ***, drive home, and then take the wife to dinner .

jt321

Were you looking to sell the PSS tires? Im thinking about getting the 245/275 PSS this weekend, but if your looking to sell your current setup let me know!

lobuxracer

iTrader: (2)

I have PSS 245s on the front now. 275s are showing up at the door tomorrow. They're all going on a set of 2014 wheels. I doubt I'll have any issues with that.

I did consider going wider, but really the only wider I want needs more wheel. 295 rear and 255 front would be better. 295 on all four corners would be spectacular compared to stock, but I doubt it will fit the front.

The only way you'll know if you like it is to try it. Sorry no one can really say, but on the track everyone feels comfortable in different ways.

I8ABMR

Just spoke to my HPDE instructor and he said GO FOR IT !!! He said that the 1/2 " will make an inconsequential difference in sidewall flex but will add some grip. He said not to go over that.

I guess I will be the pioneer on this. First ISF ( I can find) with 285 SO4s rears on the track. I am loving these Michelin PSS, but the discount tire next to me will take them back and replace them with what I want to make me happy. After seeing that ISF this weekend with the wider set up I GOTTA HAVE IT !! The car looked meaner and a little more special/sporty with the wider tires. Add the exhaust and I dont think anyone around you will ever confuse us for an IS250 or 350. LOL

I even called to get pricing on an exhaust.

I8ABMR

Will be returning them. The discount tire policy is that " if you're ever unhappy with one of our tires, feel free to bring it back". What so cool about them is that you can try a tire with little to no risk. As long as you let then know in a month or so after you get them they will actually credit you the full amount and order the new ones. What so great is that the PSS were more expensive than the S04 by $260 , even at the larger size of the S04

Blzn335

Hopefully I can check out your setup soon. I'm due for some rubber soon too and was thinking about up sizing also.

jt321

Thats awesome that they are doing that for you! Im getting my tires at Discount also, good to know that they will do that.

I8ABMR

honestly I wouldnt do business with anyone other than them. I have gone to wheel and tire specialists in Tempe ( place that does RR, Ferrari, Lambo, Benz, etc) and got sold , not 1, but 2 defective sets of tires. When I would return all they would do is rebalance. Discount tire will move heaven , hell, and earth to make a customer happy.

I wish I could see that F again with that set up. I want to take a closer look at what the front will look like with the slightly smaller diameter. I glanced down at his tires and wheel at a light quickly and it seemed ok. The rears looked INSANE. Made the car look like something more special. Kind of like seeing an exotic. You look at those wide tires and even if you dont what it is....you know its fast.

I will be honest and say that as much as I have tried , I can not get the 255 Michelin PSS to break traction. Ive tried onramps, hard rights floored, and nothing. I am wondering if the oem sizes may be adequate after all with upgraded rubber ( street not track) . I will probably have them mount the 245/285 combo then call me to come look at it. If I like what I see I will proceed. If the front looks goofy I will stick with the oem PSS. I have to admit that I like the oem size with the PSS because it looks meatier and almost makes the car looked dropped relative to what it looked like the Bridgestones

I8ABMR

update: I just sent an email to my friend from high school who is a Lexus test driver to see what he thinks of the 245/285 with the narrow rear wheel. Ill update when he gets back to me.

My concern dynamically is that if the F sport sway bar dropped the undertsteer and the PSS added more grip and a more neutral feel, will the added 10mm to the rears ( pushing the difference in widths from the front to the rear from 30mm to 40mm) induce more understeer. In theory and in every suspension and chassis tuning book I have ever read it will, but it will be at a higher speed. This car is a very special car that was truly engineered for performance. I just want to make sure that we dont upset the balance . Many auto engineering articles and forum posts say to upgrade the quality of the rubber before you go wider..........but wider just looks so much better

flowrider

iTrader: (9)

Wow, you're really overthinking this thing. As you know I have the oversized S04s. I also have the F-Sport rear bar. My F has far more neutral handling now than when it was stock. I tend to drive aggressively, and I can take on and off ramp sweepers at a much higher speed than I could when it was stock.

I guess I've been telling you for months now, (since February) that this is the right thing to do. IMO, the car is undertired and benefits greatly from this change. Trust me, you won't be disappointed.

I sent you a long PM on the subject back in August giving you a little insight about my background..

Lou