JPS

Been running the stock 17 7 & 9 with 235/45 and 275/40 Toyo RA1s for Red level DE. They fit and work, but are obviously a little tall and fat, and subject to some rollover, esp. when new. Oh, and I don't trailer the car, so need a DOT and non-slick.

Switching to prob 18 8 or 8.5 and 10. So couple Qs:

1) For DE, not racing, any real difference in the performance of 8 vs. 8.5 in front?
2) What would be the ideal size tires for these?
3) I like the price point and wear point on the RA1s. I know I'm giving up some time over MSPC or Hoosiers or a myriad others that have a much higher cost per track mile. What would be brands that would have the size from #2 above?
4) Am I better off staying with 17 and getting wider 17s?

I was thinking maybe Toyo RA1 in 245/40/18 and 275/35/18, which is 25.6 matched diameter.

Thoughts?

David in VA

1. Don't really know, I run 8's and 10's which work fine.
2. Running 235/40/18 and 275/35/18 which I like a lot, no rubbing and well balanced. I tried 245/40/18 and they rubbed, I would think 245/35/18 would be perfect but not widely available.
3. You may want to consider Nitto NT-01's, I like them as much as RA-1's but less expensive and better front tire size for me.

Hope that helps

utkinpol

RA1 are very good but you`ll have tough time finding them now. 18" sizes are pretty much gone, may be 17" are still lurking somewhere. Nitto NT01 uses same compound. R888 are said to have same compound too but they have different rubber used to mold so when wear goes close to tread bars you loose pretty much all traction and new they have too high tread so they feel greecy. you have essentially 2/32th of good grip (means R888 in reality are very expensive compared to RA1s which you can cord down from full tread not loosing much grip) when you shave them to 4/32th or 3/32th and drive them a bit.
but R888 are everywhere and can be found decently cheap.

if you never tried V710 kumhos you may be surprised also - they grip quite well in dry and slightly wet conditions, better than RA1s, and survive i would say 50% longer than hoosiers.

Core question is - do you need to drive to track on those tires and do you want them for dry only or dry/wet mix drive?
For track/street mixed driving and dry/wet mix full tread RA1 tires after they lost first 1-2/32th of tread are awesome. not sure if there is better all-around 'compromise' tire. R888 is OK too when new in wet. NT01 is much worse than RA1 in wet but a bit better in dry imho. some run NT01 in front and RA1 in rear.
for me - any r-comp tire that costs less than $200 is good, and $150 tire is an awesome tire.

JPS

Thx. Yes, must drive to/from the track (live in Manhattan and parking for a car is enough of a bitch let alone a truck & trailer). I don't drive much in the wet...not racing and therefore just not very fun to me.

utkinpol

'streetable' good DOT r-comps are quite limited in selection, I think listed them all.
kinda surprising tire which is not pure r-comp is hankook r-s3. if you do it for fun - it may be on par for street/track use, it takes in heat well and holds well in dry and not deadly in wet, some scca people had quite good feel about it, kinda liked it better than R888.

RA1 is still the tire to use imho if you`ll find any. good luck with your search.

certz

I just put the Yokohama ADVAN Neova AD08's on my C2S - 235/40 and 295/30 18's. They are fantastic, but you would probably need the 225/40 and 285/30's to maintain a good diameter ratio. I have also run the Dunlop Direzza Sport Z1 Star Spec's on my C2 and they were very good and predictable on the track - these also come in the sizes you mentioned above.

utkinpol

a guy next to me tried ad08 in rain after his half-worn R888 and did put back r888 cursing at AD08. i was surprised but, well, for what it`s worth.

I drive z1 start specs in 235/275 as my street tires too and use them in bad rain, but they are worse than r-s3 in dry and neither z1 nor ad08 take heat in well on track imho. what Z1 is great for is wet cold 50-60 degrees spring/fall days as it starts to grip realy fast and does not need to be heated up much.

r-s3 needs to be warmed up a bit, but still bit less than 'normal' r-comp need. at least that is what I heard of them so far as I did not have a chance to try them myself yet.

certz

Interesting - I have had different results, though I have not driven either tire on the track in the rain. I did not have (over)heat issues with either tire - what pressures did you run your Z1/AD08's. I run 36-38 hot. I have heard of problems if you start running low 30's for your hot pressure.

utkinpol

z1 i drive 33f 36r hot, which is pretty standard imho. above 38psi z1 start acting weirdly. i did not run on ad08 ever, as i have heard mixed reviews from people i know. some say it`s good, some say not so good, as there is no consistency in reviews i kinda just skip it...

DanR

what benefit is there to this?

DAVISRILEY

I had great luck with Dunlop Direzza Star specs on the 964, I just don't know if there is a good size for you.

rlm328

Dino 20w 50

MUSSBERGER

I have a set of those that I bought for "rains" I just put them on my 930 with fake fuchs. 235/265. Obviously just street driving but they do seem like a nice tire.

J richard

I put the star specs on my track prepped RSA as street tires and ran a drive to track event with them;very impressed. In order of preference NT01, RA1, R888, I used to run khumo 710 but had a bad batch a while back and never went back. (all on a 964) but the weight is similar. It's getting harder to find r rubber in the <17" anymore I moved to 235/35-18 and 285/35-18 and loved it. Wheel weight starts to become an issue, you want a light one.

Bill Verburg

I just switched from 8 & 10 to 8.5 & 10 x18 same tires 225/40 7 265/35 MPSC
the new setup goes a long way to eliminating the understeer that I have been plagued w/. The car just turns sooo much better.

I also had the car aligned but need to get the specs, it shouldn't be different from last year though

one other change was a rebuilt l/f shock which could be contributing to the better turn in. but the improvement was on both lefts and rights so I discount that.

the 18" sizes that you would use if you stay w/ Toyo RA1 are actually a tad shorter than the 17s you have been using, at least at the drive wheels

17
235/45 > 25.4"OD
275/40 > 25.7"OD

18
245/40 > 25.6"OD
275/35 > 25.6"OD

to me the ideal sizes for a n/b 993 are,
8.5 w/ 245/35 x18 @ ~24.7"OD
10 w/ 285/30 x18 @ ~24.9"OD