trebien

Mooty, and others...

I understand the R7 isn't available in a smaller front than 265... but is the data supporting that running a larger front tire is helping much with handling, balance, and the understeer concerns?

Or are most people able to work that out via alignment and suspension setup?

In a perfect world, is it looking like it would be preferable to run a larger front than OEM for better handling?

Inquiring minds want to know...

usctrojanGT3

My car has about 6k miles and 10 track days. I was crewing through tires after 2-3 track days (front outside of the tires were getting worn out fast despite -3.0+ camber). The problem was the front springs being too soft which caused the fronts to roll over in turns. Not that the problem is fixed I got 18 HCs out of my Cup2s (need to go more camber as my front outside tire corded).

usctrojanGT3

R7s will be about 2 seconds faster on a 2 minute lap track.

EGOKLR

Looking forward to your review of the RE-71Rs. Would you happen to have the spring part numbers?

bhk1004

Is upgrading springs lower the car? I really don't want the car to be any lower haha.

morefun

I've looked at the Nt01s referenced but noted that delta in the rolling diameter between the two is greater than 5% and am curious as to whether it will be an issue with the ABS as on 987s.

At this juncture given what's available in inexpensive track rubber, the RE71r looks to be a good option as I don't want go on the hoohoo crack pipe. R888s would work and have a smaller (matching) diameter to shorten the gearing but, it's hard to find anything complementary out there about R888s.

morefun

Springs can be purchased in various hts./lengths plus the GT4 has adjustable spring perches giving ride ht. adjustment +\-

Shockwave

Love RE71R! I use to religiously use Hankook RS3's but since trying the Bridgestone's i haven't looked back.

mooty

]
car pushes
i also have guards LSD, which pushes more
265/295 shoudl be good. if i can and they make them (they dont) i put even larger fronts.

alingment wont dial out all the push



bbs +50 all around iirc
9 and 11. i woudl have taken 10.5 konwing what i know now. but close enough. i am no pro.

usctrojan runs the same size. no rubbing

usctrojanGT3

Yup, no rubbing at all but I do have to run a 5mm spacer in the rear.

brel

RE-71R is a fantastic tire. It's the tire of choice for SCCA SOLO Street and Street Touring classes. I had them on my 986 Boxster and liked them much more than BFG Rivals and Hankook RS3's. Will definitely get them for my GT4, when it will finally get here.
Curious to hear how well they will work on the GT4 on a track.

ShakeNBake

I've always operated under the assumption that bigger is better. There is virtually no data out there on the subject because I'm aware of just a handful of people even tracking these cars at this point with 19" tires. An alignment and 265s have fixed the balance issue for me. On 20" OEM Cup2s, there is more understeer than with 265 hoosiers on the same alignment. At the ultimate limit, there is still a little understeer with 265 hoosiers, but it's more that I need to learn how to drive a mid engine car properly.


Possible tire options for 20/19 with some fringe sizes - see Tires tab, scroll down to GT4 section:
https://docs.google.com/spreadsheets...it?usp=sharing

trebien

Thanks, great info. I was about halfway down the rabbit hole on a similar spreadsheet.

I had also come across:

RE-71R in 245/40-19 and 285/35-19 as discussed.

Advan AD-08R available in a lot of sizes, but I have no experience with:

245/35-19
245/40-19
255/30-19
255/35-19
265/30-19
265/35-19
295/30-19
305/30-19

https://www.yokohamatire.com/tires/d...n_neova_ad08_r


I am not sure how the AD-08R perform, but there is a lot of sizing availability to create combos with 255 or even 265 fronts. They are also reasonable in price, and with the lower profile give a slight advantage in virtual gearing ratio.

Of note, the 255/30-19 and 295 and 305 sizes are XL rated. But the 30 ratio of the 255 might give rotational/TC issues.

Anybody have thoughts/experience with the AD-08R?

fishing

Thanks for sharing!

O5C4R

tough long lasting tyre, not really a proper semi slick, the tread wear is impressive I have gotten around 8 days out of mine on a c2s.