josh > wrote:

>Leon van Dommelen wrote:
>
>> Do a new alignment and post the old and new numbers to satisfy
>> our curiosity.
>>
>
>I will soon when I get new tires.
>
>However, I do recall that they could not achieve all of the alignment specs
>I wanted (as I posted) because the car was at the limit of adjustability. I
>think mostly they got as much neg. camber as they could which was less than
>what I wanted on at least one corner.
>
>>
>>>So this third set of tires (which I hate... Falken Ziex 512 185/60-14's at
>>>34psi rear, 35psi front),
>>
>>
>> What were the wear characteristics on the previous two sets?
>>
>
>Orig. tires were whatever 2K cars came with Yoko's... wore relatively
>evenly but rear wore faster than front obviously. Second set wore dead even
>(Pirelli P7000's I loved!!), rear faster than front.

Seem to me your alignment was fine. If your latest tires float
all over the place, I would just ignore what their wear pattern is.

>>
>>>and after about 10K they wear as follows:
>>>
>>>front left, severely worn outside edge, very little wear elsewhere
>>>front right, worn outside edge, not as bad as left
>>
>>
>> Increase negative camber to take wear off the outside edge?
>
>I think with prev. alignment it was at the limit. But the alignment could
>have drifted.

Based on the other tires, personally I would guess the problem is with
the junk tires yielding so much their edge is exposed. In short, if it
were me, I would replace tires, not alignment.

>>
>>
>>>rear both sides, inside edge very worn, and rest of tire about 2x as worn as
>>>front
>>
>>
>> Decrease toe. Increase camber if evidence of wear on outside edges.
>>
>>
>>>also, the car of late (last couple of months) has gotten extremely
>>>tail-happy. just regular corners, like in and out of parking lots, etc.,
>>>send it into throttle oversteer very easily.
>>
>>
>> Seems easy. You just told us that the thread areas you drive on
>> are severely worn. If you no longer have good rubber on the road,
>> you do not have good traction.
>
>yep.
>
>>
>>
>>>and did I mention, I hate these tires? ultra flexy and other than having
>>>good rain/straight-line grip,
>>
>>
>> Interesting in view of the high pressure.
>
>High pressure does not help too much with the flexy/slow/vague feeling.

Actually, I was talking about good straight line grip. All things
being equal (they usually are not), rubber works better the lower the
pressure. But on thinking it over, the junk tires probably help on
the straight line since they are flexible enough to completely ignore
the camber of the wheels and meet the surface flat. So I am no
longer surprised.

> The
>tires will take up to 44psi and I've pumped them that high and it just loses
>traction beyond my chosen pressure. Below ~33 they are very flexy and
>basically feels like I'm driving a mini-van.
>
>>
>>
>>>bad grip in general.
>>
>>
>> Well, that is already noted in the product reviews on miata.net.
>
>Yeah, well the reviews on miata.net were not very uniform when I got these
>tires.

Be careful with the numbers. Apparently, Ziex tires with slightly
different numbers are very different, believing the reviews.

> Choices are slim for really terrific 14" tires that will last much
>more than 10K miles, or cost much less than $100 each, nevermind both, and
>really nevermind rain performance. Next time around I guess I'll give on
>one or the other parameter. For the $36/ea I paid for these tires I didn't
>expect much.
>
>
>>
>> Not clear to me why you need the toe then. Though I believe toe
>> in at the rear does help stability. Lannny's alignment may be a
>> better choice.
>
>That's the main thing I'm tryin to get out of this discussion, what
>alignment specs SHOULD I go with? At $60/ea it's not something I want to
>have to go experimenting with all the time. Basically I'm looking for
>go-cart feel from the car as much as possible. I could care less about
>whether it's twitchy on the freeway. And I need the tires to wear evenly if
>I am going to put sticky rubber on there that wears fast.

Frankly, I think you are not going to get a satisfactory answer on
the question as posed above. At least I cannot imagine anyone
being able to analyze the issue and produce the optimal (versus an)
answer.

For what it is worth, my non expert take on it is:

1) You are not going to get any real life time out of performance
tires. To go for a "Save the Tires!" alignment with performance
tires you get the worst of *both* worlds: lousy handling and
only marginally improved short life span.

2) Getting a *good* performance tire, (not the ones you have now,
but don't ask me for a recommendation), you need to make a
decision whether you want handling or performance.

a If you want handling, look at Lanny's page. I just looked at
it myself once more, and I am a believer. They are technically
sound and agree with my own impressions. Note that I am *not*
a precision driver by any means; I am not going to argue about
a few tenths of a degree.

b If you want long tire life, set camber and toe to zero and drive
like you grew up in Tallahassee.

You might get a meaningful answer in this group from someone for the
question "What is the best tire and alignment to get the best street
performance, blast the cost?", or "Can you tell me a tire that lasts
many miles gently commuting, and good rain and straight line grip when
needed in an emergency?" but not on "Can you give me alignments and
performance tires that produce incredible grip while lasting a
long time?" Any good answer to the last question is *equally*
bad, since what you gain on one part, you give up on the other part.

Leon

--
Leon van Dommelen Bozo, the White 96 Sebring Miata .)
http://www.dommelen.net/miata
EXIT THE INTERSTATES (Jamie Jensen)