AX racing on street tires - loud is good?, pushin the limits and lookin for more |
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AX racing on street tires - loud is good?, pushin the limits and lookin for more |
Chris Pincetich |
Jul 18 2007, 06:44 PM
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#1
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B-) Group: Members Posts: 2,082 Joined: 3-October 05 From: Point Reyes Station, CA Member No.: 4,907 Region Association: Northern California |
I gotta stick to the tires I have now for 2007 due to AX class points and my budget.
I have 195/50 Dunlop 2000 Sport (I think) on 15x6" alloy rims. I got these because I was worried about fitment of 205s and never guessed I'd becaome an AX addict. (IMG:style_emoticons/default/happy11.gif) These tires seem to get more slippery as they warm up. As a result, I end up fish taling a bit. I tend to 180 slide about once a day, and can keep the back end from swingin around 90% of the time. Some times I mash the brakes, turn in fast, get about 10-20 deg fish tail, and hook up heading right for the next apex. YEAH it feels great and I hear the tires squeel. Other times I have a smoother approach and lots of squeel all through the arc of the turn. Sometimes I'm smooth and don't hear the sqeel. With so many turns adding up to my time, it is tough to tell which approach is fastest. I don't feel like I kill any speed on my little slip slide and hook up and when I watch others it looks fast as long as the tail isn't swingin out wide. My AX book (with the 911 on the cover) talks about the friction circle, and I think I need more info here. It says that pushing the limit up to the grip release is fastest, and then hints that sometimes going a little outside the cirlce is fastest. Losts of allusions to pushing the limits but no "one size fits all" explanation. Is this loud sqeelin approach as good and fast as it feels, or am I just enjoying the ride and going slower than I could? At what point in the friction circle are my street tires making the squeel noise? Is the soft compounds in DOT-R and slicks too soft to resonante and make the squeel noise? (IMG:style_emoticons/default/idea.gif) I started dropping PSI this year - from 32-34 down to 24-26 PSI at the last race. Still well on the tread, not rollin over to the tread wear line. Is this extra side wall flex good? I think so!! (IMG:style_emoticons/default/w00t.gif) I know most of youz guyz had humble beginnins like me and my rustored 1.7 914 so enlighten me on the finer points of maxing out my street tires! (IMG:style_emoticons/default/beerchug.gif) |
Joe Ricard |
Jul 19 2007, 11:51 AM
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#2
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CUMONIWANNARACEU Group: Members Posts: 6,811 Joined: 5-January 03 From: Gautier, MS Member No.: 92 |
Ok I will only tell you this one more time. You need more than 30 PSi for a street tire for your car to handle well in Autocross. !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I was running 30 PSI hot on a 225/45-15 A3S05 Hoosier on 8" rims. Can you argue with 1.4 sustained lateral G's ????? |
grantsfo |
Jul 19 2007, 12:44 PM
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#3
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Arrrrhhhh! Group: Members Posts: 4,327 Joined: 16-March 03 Member No.: 433 Region Association: None |
Ok I will only tell you this one more time. You need more than 30 PSi for a street tire for your car to handle well in Autocross. !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I was running 30 PSI hot on a 225/45-15 A3S05 Hoosier on 8" rims. Can you argue with 1.4 sustained lateral G's ????? I run my 225/50-15 Kumho's on 8" rims at 24 PSI hot and have sustained 1.5 lateral g's. Tire pressures are tire and car dependent. But I agree I'd say Chris needs to go with higher pressures than he currently runs - probably 35 would be a good number. I run 45 PSI in my Falkens on my 3700 lb Mazda tank! |
Joe Ricard |
Jul 19 2007, 02:54 PM
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#4
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CUMONIWANNARACEU Group: Members Posts: 6,811 Joined: 5-January 03 From: Gautier, MS Member No.: 92 |
I run my 225/50-15 Kumho's on 8" rims at 24 PSI hot and have sustained 1.5 lateral g's. Yea I need more power. 1.4 was at an autocross. Road racing /lapping days I have no idea (IMG:style_emoticons/default/blink.gif) But the passengers (IMG:style_emoticons/default/barf.gif) (IMG:style_emoticons/default/laugh.gif) |
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