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07-27-2014, 04:04 PM | #1 |
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Direzza ZII Chunking?
I've looked around online about the ZIIs, but I didn't find anything similar. It just happened during my last event at NJMP-Thunderbolt a few days ago on a cloudy day 80 degF. This is my left front that got f'd on the first day in pretty much 2 sessions. No issues before the event.
I swapped left & right for the second day, and I took it a little bit easier on the tires, but the new left front started to do the same thing. At first the edges start to "wave" inwards, then the splices happen. Stock E46 M3 base suspension with -1.5 camber in the front, 17x9.5 ET35 with 255/40/17, no spacers, no rubbing. Anyone know why this is happening? |
07-27-2014, 06:03 PM | #2 |
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What pressures were you running them at? If you're chunking that fast, you might have them too high.
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07-27-2014, 06:35 PM | #3 |
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Or too low?
I Have them on my Evo for DEs & no issues & I'm driving the pi$$ outta of them.
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07-27-2014, 07:48 PM | #4 |
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I've been keeping them around 38-39 when I return to the paddock. A couple PSI higher makes them get slick early. It had been good for the past 3-4 DEs, but this time I guess I was pushing a little more.
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07-27-2014, 08:21 PM | #5 |
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Simple, not enough camber and not stiff enough suspension (well stock suspension) so your car is rolling on the outside edges of the tire too much BUT the main reason is that you're probably overdriving your car/tires and I am sure you are probably understeering but forcing gas to try and make the car rotate while turning in more causing the tires to scrub rather than rotate. I did this to two sets of tires on two different cars when I first started tracking but later found that it was actually slower and causing me more money lol.
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07-27-2014, 08:21 PM | #6 |
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That seems high to me. By the time you get back in the paddock you already did a cool down lap. Try 36-37 hot. Even 35-36.
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07-27-2014, 08:31 PM | #7 |
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Thunderbolt is known as a tire killer, but you still shouldnt do so much damage to these tires, as side walls are very stiff. You probably overdrive your car a little bit and you may need more negative camber up front.
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07-27-2014, 09:18 PM | #9 |
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Actually, on stock camber you want higher pressures which will help reduce how much the tire rolls over onto the sidewall. Then its a double edged sword because your pressures will be higher and the front end will be very twitchy and skatey. Then you'll understeer constantly.
As I said on M3Forum...you need camber and roll stiffness on the front axle or less roll stiffness on the rear axle. The cheapest thing you can do is disconnect the rear sway bar...not sure if that will help a whole lot. I would buy front camber plates which will pay for itself over a couple of events as your tires will last a lot longer. E46s like a relatively high front spring rates, -3.5 camber or more, and a big front sway bar.
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07-28-2014, 09:36 AM | #10 | |
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Not enough negative camber and over driving the car. (Lots of understeer) The Z2's are really sticky tires, -2.5 would really help if the op likes to plow into turns. |
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07-28-2014, 01:04 PM | #11 |
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Just curious, are those tires directional?
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07-28-2014, 04:14 PM | #14 | |||||
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PM me the details whenever please. I found a local set of coilovers, but I’m trying to find out if it even comes with camber plates. Thanks! |
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07-28-2014, 04:18 PM | #15 |
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Have you done an alignment recently? What are your toe specs?
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07-29-2014, 02:23 PM | #17 |
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Bingo. If it's 1/8" toe in each side, that's 1/4" total, which is significant. Excessive toe-in coupled with not enough neg camber can be a tire killer, especially on the track if your driving the snot out of it.
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07-29-2014, 02:27 PM | #18 |
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07-29-2014, 02:47 PM | #19 |
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So too much toe in or out can kill the outside of a tire? I thought it pertained more to the inside because of neg camber.
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07-29-2014, 02:55 PM | #20 |
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07-29-2014, 02:59 PM | #21 | |
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In his case, it probably isn't his alignment, more likely the tire rolling over, driving technique can reduce most of it, but that would mean backing off a little bit and knowing the limits of the tire. I'm not sure what his skill level is so i dont want to offend him, but my 'guess' would be that the car had to have been 'pushing' (understeering) quiet a bit to do this damage, but without being in the car it's hard to say for sure. Maybe it would be good to have an instructor observe him and provide suggestions.
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07-29-2014, 03:16 PM | #22 |
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I just got a few videos uploaded. Sorry for the crappy audio quality, but I'd appreciate any input if there are things I can do to manage the tires. I don't think I felt a lot of pushing... rather I was trying to trail brake quite a bit, and spent more time on catching the rear end wanting to come out (maybe b/c of square setup), but anyways... any criticism is welcome.
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