I have a Birkin S3, 1350lbs with half a tank of gas. Currently sitting on probably dried out Yoko A048s, in probably too wide 225/45-15 fitment. In aggressive street driving, they don't even come close to temping up, granted I've been driving at around 50* ambients. Maybe they're just too old. So for fast street mountain pass driving, and maybe 3-4 track days a year, would I be better served with a good 300tw tire like the ECS or PS4? A couple cars I drive with are impressively quick on our local "closed course" using those tires. Granted they are heavier (Nismo 370Z and C6 GS). I used to have issues getting heat into Direzza Z3s on the front on my Elise when it got below 55*. On the flip side, would a soft tire like a Federal FZ201 or Nanakang AR1 work better because of lower durometer, or will they still be quite unhappy until they get warm. Regardless, I'm probably going to step down to 205/50, especially since they're on 7" rims.
nocones
UltraDork
11/25/20 12:49 p.m.
I would run a 205 or 195 of something like the R888R or Yokohama A052 if you are looking for immediate grip during short sessions of work. They work well (Apparently) on the STS cars (~2000lb Autox cars). 225 is probably just to wide to get any real temperature without track work. I can get heat into 225 Rivals and 245 Hoosier A7's during 20 minute track sessions on a 1700 lbs (With Driver) MG midget with 170 HP but I cannot overheat them. It takes 1-2 laps to get them to feel like they are at temperature and I can't imagine driving that hard on the street at all.
With a mixed use without 2 sets of wheels I would aim toward the 205 size for your competing goals. It's possible a 195 will get to hot for track use.
My suggestion is to get the softest, grippiest 200tw tire you can. My Exocet was 1550lbs with 225/45-15s. In four years of tracking the car with some street use I just made a dent in the RE71s and the Hoosier A7s did three light years of track and autocross and still weren't dead. Was never able to overheat them, even in July. If you don't put a lot of miles on the car they will probably age out before they wear out.
Not sure about the best answer in low temps - the extreme street tires just aren't very good when they are that cold.
My Seven wouldn't wake up the chassis until it had some grip. The flip side is that they don't really wear tires, so you can run 100TW without a downside. I used to run 205 RA1s on it. Note that the Brits (who have more Sevens than anyone) don't run a lot of tyre width on theirs.
Old, heat-cycled tires basically have a higher TW rating.
fanfoy
SuperDork
11/25/20 1:08 p.m.
What pressures are you running? On such a light car, people tend to over-inflate which won't help your tires warm up.
Should I be the guy that doesn't recommend aggressive mountain pass driving in a really light weight open cockpit car?
Define aggressive? That has a very different meaning from car to car and driver to driver.
As for tires I would go with a more narrow tire in the softer compound. The 205 in 100tw would be my pick.
dps214
HalfDork
11/25/20 2:39 p.m.
I was going to suggest something in the 300TW range until I got to the "3-4 track days a year" part. If you're at all pushing hard on track 200TWs (or better) are the only thing that's going to last long term. The 300TWs are great on the street and very good in wet track conditions, but just don't have the heat tolerance for extended dry track use.
