pkh

I'm looking for suggestions for a tire to try besides RE71R on my GT4 running 19x9 and 19x10.5. Currently I run 245/40-19 and 285/35-19 sizes.

I have tried Cup2 and the 4S tire, as well as Continental Extreme Contact Sports.

On my S2000 I ran a RS4 which I loved for performance and especially durability. It was not as fast as RE71R but it was great how long it lasted and was very consistent performance.

The two things that drive me nuts about RE71R is how it falls off after 4-5 laps and how it only lasts me 4 days.

There are other tires I would like to try but don't come in the right size: RS4, NT01s, R888s

Perhaps with some creative sizing choices I could make one work?

MarcD147

The re71 doesn't fall of like you say...

What pressures do you run?

pkh

I typically aim for 33/35 F/R hot. I have done 40 days in the last year, 5-6 sessions per day, unless something unusual happens during a session my fastest lap is lap 4. Laps 3-5 feel pretty good then I lose 1-2 seconds.

Scooby921

I concur on the RE71R. They are great when cool, but being designed as a top-choice autocross tire doesn't make them a top-choice track day tire. Even starting at 26psi cold and working up to ~32psi hot they start to fall off and get greasy after 15 minutes of running. Once they start to slide they fall off a cliff and the additional sliding and heat runs the pressures up to 35psi.

I expect you'll see more consistency from an NT01 or R888, but I don't know if they provide any more ultimate grip than the RE71R. The only way any of us is going to find consistency with a street tire is to slow down so they don't warm up. Otherwise we're all in need of proper race rubber that is designed for extended runs at warmer temps.

pkh

MarcD147

ok that is the issue

you should aim for 31-32 hot all around. over 33 they start feeling greasy (there is your 1-2 seconds) and you get increased wear. 35 is killing your tires (and laptimes)

I start around 26 in session 1; come in to hot pits once they get up to 33 bleed to 30.
than after session 1 I bleed to 31 in hot pits and subsequently I will bleed them to 31 after each session.

if the outside temps increase a lot you might need an extra visit to the hotpits mid session.

marc

pkh

I have tried going out with less pressure, but then it seems like I waste first few laps letting pressures build, by the time I hit the sweet spot the tires are overheating. Once they get hot there is no getting them back. Tire pressure being low doesn't mean tires aren't overheating. The other tires I mention are much better are recovering after being overheated, this is pretty well covered in countless posts and articles out there. I am not saying RE71R isn't the best tire at setting ultimate lap times.

Anyway I didn't mean this to be talk about how to make RE71R work, I was curious if anyone has alternative tire ideas in my size setup.

MarcD147

My guidance makes them work really well especially after session 1

Scooby921

Have you considered the Pilot Sport Cup 2 or PZero Corsa? Both appear to be available if you move up to a 255/35 in the front. Should be similar to the NT01, R888, and RE71R, but being designed as a track tire first and street tire second I would think they are more consistent at warm temps compared to the RE71R. If I decide to autocross with my car I will probably stick with the RE71R and deal with less than ideal track performance. If not, then I might try the Pirelli when the RE71R wears out.

If you're looking for DOT / streetable and simply wanting more consistency than an RE71R I tentatively recommend the Pirelli PZero. Everyone seems to hate them as an OEM tire, but I find them to be quite good. I can't make a perfect apples to apples comparison being that my PZero is on the OEM 20" BBS Carrera S wheel and my RE71R is on a 19" HRE FF01, but the tires are the same 235/265 OEM width. I haven't found the RE71R to be immensely faster. Comparing lap times from the same car, track, driver, and similar weather (1 year apart) my absolute best lap on each tire is only 0.2 seconds different, with the RE71R being faster. Looking at open track, consistent and consecutive laps the RE71R is around 0.7 seconds a lap faster. That said, I feel the PZero has a wider operating range for pressure / temperature. With the RE71R I start at 26 psi and spend 5 laps babying the tires as they come up to temp / pressure. Then I get 4 laps between 30 and 32 psi where I can hammer them and run my best lap times. Then they fall off the cliff and I'm nursing them for the last 3 laps of a session. With the PZero I can start them at 28 psi cold, hammer them from lap 2, and then deal with greasy tires for the last 3 laps once they get up to 35 psi. The laps are a bit slower, but I am able to get more "fast" laps out of the PZero than I can with the RE71R.

pkh

Thank you! That is exactly the kind of advice I was looking for. I too generally hear people bag on the Pzero's but they come in the right sizes (255 up front would be nice) and seem to fit the bill on paper.

At this point I feel like I have gone through so many sets of RE71Rs I am willing to give something else a try. I don't expect to necessarily set new personal best times but if I get 99% there for more laps that will be worth it. Its so hard to get consistent with driving when the tires aren't consistent throughout a session.

Is there a flavor of PZero I should be looking at? also are they directional or can I run backwards? I always run RE71R either way unless its raining.

pkh

You may be right - but generally I don't feel like wasting 5 minutes of my session bleeding tires off in the hot pits. I am also somewhat skeptical as I have tried running lower pressures and the result is the same when the tires get too hot they need to take a break to recover, a simple cool down lap won't cut it, and pressures aren't everything. Its likely your way would get me at most a couple more laps.

Scooby921

The basic version of PZero (no additional naming) is what Porsche uses for the OEM variant. The one big difference here is that the 255/285 combo won't be in a Porsche specific (N-spec) compound. I don't know how much the Porsche compound used for the 235/265 sizes varies from the basic / standard compound. I suspect the Porsche compound is a bit softer and more grippy as I've heard from a Ford vehicle dynamics engineer that they couldn't use the Porsche spec compound on the Mustang Performance Pack because the rubber didn't play well with cold and wet. You might give up more than the half to one second I've seen because the base compound is a little harder. Here are links if you want to check them out.

https://www.tirerack.com/tires/tires...XLV7&tab=Sizes
https://www.tirerack.com/tires/tires...P0XL&tab=Sizes

I think a Michelin Pilot Sport Cup 2 is going to be a better option, but I don't have any time on them to offer any opinion or data. They are certainly a softer, stickier tire. They are track-oriented so they should be more consistent. They aren't going to last as long and they are 60% more expensive than the Pirelli.

MarcD147

Just like I can't make you believe 2+2=4 I can't make you believe my advice

Check out the gt4 forum and ask why everyone is running re71 (or hoosiers)