I hit eagle's canyon raceway yesterday for my first track session on the new bridgestone potenza S-04 pole position tires. I looked everywhere for decent tires that would fit the factory boss 302 wheels and we all know there aren't many options. I read a bunch of reviews on the various tires out there looking for track use reviews and there were enough negatives to make me not want many of the tires like the extremecontact DWs.

I ended up going with a bit of an unknown since no one that I could find has run the S-04 PP tires on a mustang. Long and short of it is that these tires are so much better than the factory Pirellis that it's hard to believe. My best time at ECR in the past was a 2:10 recorded via trackmaster and a 2:08 unofficial. I put down a verified gps lap time using trackamster of 2:04.3. I changed nothing on the car other than the tires for this track day, same tune and everything. I was a bit more aggressive and picked up a few tips from the ultimate speed secrets book I've been reading so some improvement is owed to my new tricks.

Early in the morning I was a bit worried about the new tires, they are very quiet. The car felt like it was near the limits of the tires I was used to and the S-04s were dead silent. I thought maybe they weren't going to give as much feedback as the Pirellis. After about half a lap (the course is 2.5 miles) I started to throw the car around and it stuck very well. The temps were in 40-41 range and it was cold. I spun last time I was out in these temperatures on the Pirelli's with two laps of warm up.

What I realized was that it wasn't that the S-04 tires offered no feedback, but that the limits were so much higher than the factory rubber, the s-04s weren't to the point of squealing at the same workload that the Pirellis would howl at. The fourth lap was my 2:04 run. The tires have a very different sound at the limit than the Pirellis. They do squeal and as you near the limit, they take on a different sound altogether. If you watch the videos I will attach later (uploading now) you will hear the squeal and then a sort of scraping sound. That scraping is the sound they make near the limit.

One of the videos I had a passenger in the car with faded brakes (that 2:04 lap and following 2:06 apparently boiled the fluid and the brakes were squishy for the rest of the day). At the end of the video you can hear a bike rider that was standing at the wall come up and tell me the inside tire (I am assuming he meant the driver front) was off the ground several inches when I rounded one of the really hard corners. I don’t know if that is a good thing or not, but I don't know with a passenger in the car the car turned harder than it ever could with me alone in that corner on the old rubber. What I do know is that the factory tires let go well before the sort of grip the s-04s produce. I had to completely relearn my lines and braking points on these tires.

They heat up very quickly and even after 12 or more laps at full speed they still have the same sort of grip and feedback they had early on. They do get a bit more slippery feeling as they heat but they are still controllable. I actually liked them better once heated because the car was much easier to rotate and control with the throttle. The sidewalls are stiff on the track so they don’t roll over at all, they also didn’t chunk in the slightest. the shoulder of the stock tires was all chunked up after my first track day. Turn in is crisp and precise as well. I really love these tires; I highly recommend them to any of you looking for new rubber that is cheaper and better than the factory tires. The set installed was about $1450.


It's also worth noting that a friend of mine with many, many years of road racing under his belt that runs a caddy V on coilovers and slicks rode with me at the end of the day and all he could say is that he could not believe the grip the car made on those tires. He said it was faster than his car on the coilovers and slicks through the course (granted I have more power than his V).

 

Shane,

That is some impressive information regarding the Bridgestones. I guess what is really interesting is the fact that you are tracking in 40 deg. weather. I can't imagine how they would handle in warmer temps. Can't wait for the video!

What were your settings as far as front and rear?

 

one video up, connection is slow tonight. i used 5/5, 5/4, and 4/4. fast laps were 5/5. didnt likr 5/4, 4/4 was ok

 

Cool video and nice driving btw the car sounds awesome!

 

Great news as I plan on ordering these myself in a few weeks.

 

I had looked at a new set of stock P-zeros for the car post winter storage as the tires were toast. Might go for the Bridgestones now. Thanks.

 

My rear tires are getting low? what would be the down side of just getting the rear Bridgestone Potenza S-04 and leaving the front Pirelli's?

 

huge amount of difference between the grip the two tires provide. i suspect you would have some strange handling at the limit, the fronts would give way while the rears were still gripping. IDK for sure.

 

Other than track use I would think that should not be an issue which are my intentions.

 

yes if you don't track i see no issues with that.

 

The S-04s might not be a problem due to the rigid sidewalls. I had the same issue with the rears and replaced them with some Hankooks that had a softer sidewall. The combination of softer sidewalls in the back than the front made for some weird handling. The back of the car would move laterally more than the front so it always felt like the back was breaking loose every time you turned. Then at higher speeds you could feel it with just small movements of the steering wheel. It made for a very nervous ride. I replaced them with the OEM tires after a week.

 

It's never a good idea to mix tires, especially on a high performance car and again, especially on one with a staggered set-up.

 

Yep, it was a lesson learned for me.

 

Shane, how many track days did the stock Pirellis last for you?

 

well my first 2-3 were tepid while i got used to the track and the tires were fine. it depends on how hard you drive and your track, mine is roughly on tires and brakes. I'd say 5-6 hard days on the stock tires at least. keep in mind i DD the car so it had 10k on the clock before they were dead.

 

Thanks for the info. I was wondering about how many track days I have before I need to start thinking about replacing them. It's not my daily driver and I'm not pushing the car really hard yet on the track, but this gives me an idea of how long I have before thinking about getting more tires and/or wheels...