So the Ecsta SPTs on my Toyota are about 5 years old now. They have about 15-20% tread left but have been totally hard and crusty for nearly the last year. So heat cycling and age did them in before tread wear did, and I was never gentle on them.
They were great as street tires but as track tires they could be better. Since I haven't worn them bald even after doing so many events on top of a solid 2+ years of DD'ing, I know I can afford to use tires that will wear faster.
I'm planning to go with either Bridgestone RE11s or Dunlop Z1 Star Specs as replacements, whichever I can find.
Now I've been thinking of getting some 13" rims and putting SPTs or something similar on them to use as street wheels. The roads are bad around here and the new coilovers don't make the ride any softer so another 2" of meat on the wheels would be helpful.
I don't drive the car that much these days (maybe a total of 20 days of DD'ing out of the year plus 4-6 events - mostly autocross / gymkhana, maybe a few laps on top of that) so they won't get heat cycled or worn so much, and there's nothing you can do about age...if I get street wheels I'm worried I might just end up with both sets of tires hitting 5 years old in good condition. But, if I stick to a single set of wheels I'm worried they'll go crusty prematurely. I want to get at least 4 years out of these.
What do you think?
Score a set of junk yard or CL wheels like I did.
Resurrecting old thread up because I just ran across a cheap set of rims & tires that could work as street wheels. I've got a set of Star Specs ready to go on the current rims before the next event.
So back to the original question, with my usage case will saving the Star Specs for track use only help them last long enough to justify the cost and hassle of a second set of wheels, or will they just have more rubber on them when old age or heat cycling does them in?
Star Specs aren't ideal for dedicated track tires. I doubt their heat tolerance is any better than the SPTs, in fact it may be worse. Star Specs seem to like cooler temperatures. I'd keep the Star Specs as daily drivers and get something more heat tolerant like RS-3s or XSes for track use.
Well I got the Star Specs primarily for autocross (with a good chance of rain in mind), I don't really do any track days anymore so I don't need tires that will stand up to repeated hard laps. I hope they'll work well for autocross because I just spent a metric E36 M3-ton to have them specially imported 
I couldn't find any decent tires in the right size locally, if I could have got another set of SPTs from a local retailer I might have just picked those up for much less.
I know the heat tolerance is in the same ballpark as the SPTs or possibly lower but I never had a problem with those getting "melty" in an autocross. At the last event we hadn't had any sun for a few days (thick cloud cover), the track was relatively cold and everyone running summer tires was struggling for grip. That's the kind of condition that I'm equally likely to face (likely a wet track too) vs. a hot and dry track.
I see--they are expensive Star Specs. I think they will be just as happy being driven on the street with the occasional autocross. If the car is going to sit for a long time, remove the wheels, bag, and store them inside.
I am also considering another set of SPTs as daily drivers. Mine are still sticky, but they are probably about to show cords.
Outside of R-compounds there is nothing remotely performance oriented in 13" wheel size. With 14" wheels you have the Star Specs or RT-615Ks. I am driving the Saturn around on 14x6 BMW Bottlecaps with 185/65R14 X-Ices. They don't grip much, but they ride nice. I am tempted to get the cheaper 195/55R15 Star Specs for it.
If they still look like that I can tell you they're not too close to being corded. I've done 2 more events on the SPTs since I originally started this thread, and one pair has probably less than 1mm of tread left before they're fully bald (I can already feel more grip on that pair vs. the deeper-treaded ones) and no cords are showing.
The inside shoulders (on the bottom in the picture) are bald. One has a bulge on the inner sidewall from an accident, but they keep working fine--set FTD at an autocross in October with them. These are just 205/50R16s--the 325i could use a bigger size.
