Diyman25

Test this new set up atTrack day,
255/40/17 on 17x9, From my experience on Caterham I know AR-1 is pretty decent tire for the price~

With large thread block , I was able to brake later then, full thread Tire last times I use
Due tire side wall on soft side, and the slip angle of tire is pretty big, car will go to a bit over steer with weight transfer to front on mid speed+ corner, but is very control at limit~
in 90F weather tire do get grease up around 3 lap in 3.5km course, which is not bad


With 50lap on it tire, the wear pattern pretty acceptable ~

TeamRX8

iTrader: (25)

They have an oppressive look about them ...

Diyman25

Look how much lean I get from factory sway bar and mazdaspeed shock/spring (???)
I am going to install Aftermarket front sway bar and offset knuckle bushing next time

Loki

iTrader: (1)

I would just go with proper coilovers. The sway bar will help some, but its not a complete solution and will induce understeer. Definitely recommended for the caliber of tires you're running.

Slight oversteer on weight transfer to front is what you want. Not sure you can even tune that out, or that any tire would prevent it. Again, coilovers will give you tuning control over that, which a sway bar won't. These cars excel at throttle-steering. I have certainly found speed by trail braking and throttle steering Is that what's causing the steering jitter you're doing past thr first apex in the S portion of the track? Are you trail braking into there? Maybe brake a bit earlier through there so you can be stable and on the gas sooner.

Diyman25

I am talking two separate situations
Sway bar need it is on last 4 corner is all chicane
I am loose too much time from Roll understeer
So without update to Race coilover(I might next year) with sway bar I can get some decent imporment from it

As weight transfer over steer, I think that is from lock of rebound damping on rear !!!, if I have proper track damper this issue might be not that of deal

TeamRX8

iTrader: (25)

I meant like China vs Taiwan or Hong Kong oppressive. I know my jokes suck, but come on man ...

Diyman25

Ha~
Never see this joke coming (???)

Loki

iTrader: (1)

Yeah that's what I was getting at. I suppose if you increase front tire pressure you can mitigate it until you have suspension-level adjustments, but ultimately you need suspension adjustability to dial it in. I personally love how it pivots even in stock form. It's free rotation that you don't have to burn energy and front tire scrub on -- if you can keep it under control.

hufflepuff

Thank you for sharing.

Has the tire shown evidence of heat cycling, resulting in slower warm up time?

Are you able to compare speed to any other tires, such as bridgestone re71r?

How wide does the 255 run?

Diyman25

My experience On AR-1 are all limit to 13inch on
Caterham

As for Re71R I had not use that tire, but compare to R888r I like AR-1 better on limit much easier to predict

As for heat cycle , I usually clocking my best lap time on sec heat cycle (I had use like 10 set)
And tire will be 1.5sec slower average on 4th heat cycle
This time thread almost to flat , I usually will finish one set of tire in less 1.5mo time (track only )

hufflepuff

Sounds like the AR1 fall-off from heat cycles is pretty severe.

How is the grip, especially cold grip, of the toyo R888R, compared to the AR1? I'm looking for a tire for autocross, circuit sprints, and hillclimbs, where i get little to no tire warm-up time.

Diyman25

Well
Depend on
Mabe i am over driving this poor tire
My friend just went to 12hr fun endurance race
He was guest driving RWB Porsche and use AR-1 last full race too

hufflepuff

I finally got to watch your video. Nice driving! That looks like a fun circuit.

I assume in the pictures you shared those 255/40/17 are mounted on a 17x9" wheel? Do you think that they might work better on a 17x9.5" or even 17x10" wheel?

hufflepuff

I finally got to watch your video. Nice driving! That looks like a fun circuit.

Given that the pictures you shared those 255/40/17 are mounted on a 17x9" wheel, Do you think that they might work better on a 17x9.5" or even 17x10" wheel?

Diyman25

Thanks ~ build my Rx8 for track day !! Is best handling car for the money

I think due to nature of AR-1 soft sidewall
Wider rim Will improve tire handeling character