Split between AR-1 and Z232 RS-4..

[kyrix1st]

I will be tracking my car at Okayama international next month, for one session only to grab a general understanding of the car and move forward from on track impression.

Current settings
-stock EDC suspension
-stock brakes with Endless/Project Mu street~track pads (MX72 or HC+ respectively, haven't decided yet)
-catless x pipe+stock rear
-MS stage 1 intake
-Enkei GTC01RR wheels 10.5j all around.

Track Condition
Track's around 1:40~1:50 long per lap, with abundance of mid to high speed hairpins after long straights. Last corner pulls huge lateral Gs such that you will experience fuel starvation unless the tank is more than 3/4 full.

Question
Q1. I need some verdicts on each tyre or comparison of lateral grip.

I understand AR-1 is nearly a slick tyre while RS-4 is semislick. However,

AR-1 only comes in 265/35/18 (around $100 per corner)
RS-4 comes in 265/35/18 and 275/40/18 (around $180 per corner)

Q2. Fitment on least neg. camber (max -2.0 per side I reckon?) without camber plates?

Since I intend to run without camber plates for this run, AR-1 seems like a more logical choice, but I do know that Nankang tyres are generally wider than indicated. If anyone has experience with either of the tyres please share!

[ricardofors68]

If the track surface is as rough as others near Tokyo I would use the RS-4, you would have more of a street oriented compound, my logic being that it should last you longer with no big difference in the grip available to you specially if you are just learning he car at this stage.
Good luck and please post pics if you can.

[macdude357]

If you have 10.5 inch rims, I'd even take a look at the RS-4 in 285/35/18. According to Tire Rack, they have a 10.6" tread width and a 11.7" section width which is only a couple of tenths wider than a 275/35/18 NT01.

[kyrix1st]

Originally Posted by ricardofors68

If the track surface is as rough as others near Tokyo I would use the RS-4, you would have more of a street oriented compound, my logic being that it should last you longer with no big difference in the grip available to you specially if you are just learning he car at this stage.
Good luck and please post pics if you can.

Might as well use RS-4 for my street wheels (19 inch LA220) and see how it handles first then make a decision on 10.5j. Will keep it updated.

[ricardofors68]

I'll let you know what I go with and first impression as well. Good Luck.

[kyrix1st]

Went with 265-40-18 RS-4. Bigger ones are not available (not in my country) & I wasn't sure if stock EDC suspension with lowering springs could handle the camber to put 275 in the front. I'll upload the fitted wheels soon... after an alignment.

[kyrix1st]

These are some big ass tyres. Around 275 mm (10.83") in width from rough measurement although the brand marks it as 265mm. Waiting for my Enkei wheels to arrive..

[kyrix1st]

My head hurt like hell on the day, so I couldn't take any pictures + wind was blowing so hard it would rip your clothes off. Stock pads show its limits on Ventus RS-4s it seems, as it locks too easily on threshold braking.

Tyre Impression
Rear spins a lot because autocross/gymkhana doesn't get enough heat into the tyre. I actually preferred it this way because tight turns in gymkhanas usually require certain slipperiness in the rear, and the tyre characteristic matched that well. OEM handbrakes are no good for 180 turns, so I clutch kicked to gain momentum out of the corners. DCT guys must be hopping their tyres like hell in these corners

Tyre condition
I went with 36 psi cold all around. It was broken in for 100km under 80km/h. this autocross day saw around 6 laps total, since I got there in the afternoon.

Car Impression
Some say they should get F82 for more power.. I say get more tyre sets for skills. I can feel its weight on last two corners, but that's about it. Power is very linear, which provides smooth lateral acceleration out of tight corners. M-diff felt a bit lazy to lock at times, but that's the price you pay for overall balance.

EDC suspension was surprisingly well organized for this application, but I felt the spring rates were too soft in the rear.

With moderate weight reduction (~100kg), harder springs and semi metallic brake pads, I reckon the car could go 2-3 seconds faster.

[kyrix1st]

Got the camber done this week, only removed alignment pin. Slight rubbing with 265/40/18s on the wheel wall at near full lock; I suspect this will go away with 265 35 18. Not bad for the first try!