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Scootin159
11-12-2013, 02:03 PM
When I swapped onto my snow tires yesterday I noticed that my OE P Zero's were completely corded on the inside shoulder. The outside edge was thin, but maybe 1-2/32nds above the wear bars. The rear tires look nearly brand new, not sure what full tread depth was, but I would believe that they're still at it.

That set has maybe 5000 miles (+ about 50 autocross runs, but almost exclusively in low-grip wet or cold conditions), which is pretty low IMHO for a 220 TW tire - I used to get about 10,000 miles/set with 140 TW tires and similar usage from my STI. I suspect this is just a symptom of FWD demanding so much of the front tires, and in the future I'll know better that I need to rotate them a couple times during the summer if I want them to last a full season.

My main question though is - if I get the front end aligned to have zero toe, will I screw up the handling? I'll admit all my experience with alignments comes from a RWD perspective, but in that world I would typically dial in a lot of front camber (~-3.5 degrees) and zero toe - which would give great handling and great treadwear. Do FWD cars need toe-out in the front to get any decent turn-in?

Scootin159
11-12-2013, 02:05 PM
Also - would it be best to go with another set of P Zero's for the front for next year to keep things balanced, or would I be ok to put something grippier on the front end (Rivals, DZ2's, etc) while keeping P Zeros on the rear? Keep in mind sizing likely won't match if I mix & match - will having different OD tires on the front & rear screw up all the electrical gadgetry?

trevc
11-12-2013, 03:02 PM
I love this site for alignment tips among many others.
http://farnorthracing.com/autocross_secrets22.html

abarth&911
11-12-2013, 05:48 PM
With the stock Pirelli I did about 6000 miles and somewhere around 60 AX runs in warm weather. I did tire rotation and all 4 where a the wear bar with maybe slightly more wear on the inside edge.
I now have the D ZII and the grip is much much better, putting D ZII in front and the stock Pirelli in the back will make the car tail happy for sure. If you want rotation will get it for sure. The spec say the overall diameter is almost the same so the electronic should not be confuse.

Scootin159
11-12-2013, 06:11 PM
Hmm... not so sure *that* much rotation would be a good thing. I almost exclusively autocross the Fiat in the cold & wet, since all my dry events I bring the Formula 500 out instead - and a little less rotation in the wet isn't necessarily a bad thing. Debate will be if I want to give up the possible grip of the DZ2's or if I want the better balance of the all P Zero setup. Then again, the mixed setup would probably give the best lap times - just underdrive it a little at turn-in (pretending you have less grip in the front to keep the rear in check) and then use the added grip at corner exit where you need all the front end bite you can get.

I assume you're running the 215/40-17 DZ2's? How's the responsiveness of running the wider tire on the stock wheels up front?

jguerdat
11-13-2013, 08:30 AM
I noted relatively fast inside edge wear on my Pirellis, too. The ZIIs don't seem to be wearing the same way but then I have more autocross runs on them. The issue of responsiveness is rather an apples and oranges comparison since the ZIIs have a stiffer sidewall. Besides, the increase in width is only 10mm so I don't see much issue.

The extra rotation could be interesting. I'd think it depends on your driving style more than lot conditions since driving in the wet is just like in the dry, except slower. If you're into left-foot/trail braking, the extra rotation might bite you in the ass. For me, I'm still dealing with charging the turns too hard, leading to understeer, and not knowingly trail braking except by accident. I can't make the rear rotate even with the Neu-F rear bar unless I happen to carry braking into the turn.

BTW, my alignment was dead-nuts on spec when I checked it.

abarth&911
11-13-2013, 11:13 AM
Yes 215/40/17, To me the turn in is better and they don’t seem to loose grip suddenly when pass the edge.
I did only 2 AX with them so far and both where high speed one, high 2nd and some 3rd gear. Last Saturday
we had a long slalom 8-9 cones and also a very fast lane change in 3rd gear and the car transition very well.
From those 2 AX the car felt to me like it can used a bigger front sway bar.
I might do another AX this coming Saturday, this one will most likely be slower in speed, the lot doesn’t seem that huge, we will see.
For reference, a set of Eibach Pro-kit spring and the Neu-f rear sway bar is on the car.