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So my new Sumitomo HTRZII 215/45-17's showed up (Tirerack $94) and I've got an appointment tomorrow to have them installed, so that means that the SO2 PP's have a very limited life now.
I inspected the S02's last week. Each tire had at least 1 screw/nail in it, and all were down on tread. LF and LR were just about to the wear bars, but the RF and RR were past the wear bars. The RF actually had some cord showing on the inside edge. Probably a result of my experiment w/ neg. camber and toe-out alignment, heh. I swapped each side front-to-rear, but that still left me with a tread inequity left-to-right.
Fortunately I live near two separate full-clover-leaf highway interchanges. (I-5 to Florin Blvd and 99 to Florin Blvd). That means you can drive all 4 sections of the clover without stopping, just go right 270 degrees/straight/right 270/straight...you get the idea. Yee-haw! Just the thing to beat the left side tires to death with.
First session: unknown pressures (baseline)
This was mainly to get the driver (me) into the rhythm. I found that it was easy to scare myself at first, but not easy to upset the car. The front tires always turned in w/ slight understeer and continued to have understeer while applying throttle mid-way through the turn. There was no lift-off oversteer, much to my dismay. So I tried hitting the brakes hard in mid-corner to bring the rear out - that just triggered the ABS, which killed the fun in a hurry. Blah.
Second session: Front 32.5 Rear 40.0 psi
This was a better setting. With a fatter front contact patch and a smaller rear c.p. this tuned the car closer to neutral. Going into the corners under balanced throttle, the car still had a slight understeer, but reduced compared to #1. Going into the corner with trail braking produced the best result: a lot of car rotation right at turn-in (slight oversteer) and then a steady attitude transitioning to slight understeer as I added more and more power. At the end of this session I measured pressures again:
FL 36.0 (+3.5) FR 34.0 (+1.5)
RL 42.0 (+2.0) RR 40.0 (+0.0)
As you might expect, continuous braking and right turns works the FL tire the most, followed by the RL tire.
Second session: Front 36.0 Rear 36.0 psi
Blah Blah Blah. This session just didn't feel right. The rear of the car wouldn't drift at all, so I became more aggressive with the turn-in and trail braking. A few times I think both front and rear outside tires rolled over on the sidewall, indicated by changing sounds from high-pitched intermittent squeals to continuous groaning/dragging, while the car drifted completely off-line.
These S02's have tenacious grip, and I'll be sad to see them go, especially since I'm moving down market with the HTRZII's. Oh well. I still have one more night to work them out.
My SPG remains the handling king with less body roll, better steering feedback, and it is easier to provoke oversteer when car rotation is needed.
'98 SET 5-door
o Abbott Springs & front suspension Bushings
o SAS rear sway bar
o 9-5 Aero wheels 17x7
posted by 63.207.93...
, Thu, 11 Apr 2002 00:43:49
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