brian1234

I plan on running NASA TTA this year and 295 is the max tire size allowed (without adding points that would bump to TTS). So the question is whether to run Hoosier R6 295/35/17 or 295/30/18. Basically run fronts all the way around or rears all the way around? I've got 6 rears and 2 fronts right now. Not sure if I should just buy tires for the wheels I have or get more wheels.

Another option is to take my T1 bars off to get some points back and run Hoosier A6 in smaller sizes. 275/17 front and 285/18 rear (or 285/18 all around)

What do you think?

L98Terror

Where you from? What region you going to be running in? There are many threads on this topic both here and on the NASA Forums. It seems that a 275 square set up is what is going to be tried this year, seems like a narrow tire for a C5Z maybe you should run TTS

JRL

Brian,

I ran 295/18 A6's square last year with T1 bars.
I changed to 275-18's square this year. I think the 275's are a little slower but would be faster than 295 R6's.
I would keep the T1 bars and go with 295 R6 or 275 A6. YMMV

John

sperkins

I'm guessing yours is a ZO6?

275/35/18 square fresh A6's or C91's seems to be the hot ticket for TTA in the Southeast this year. Still room for sways and air filter.
You'll get more life out of 295 R6's, but you won't be as fast. I wish Hankook made C91's in a 295.

drivinhard

one other advantage with the 275's, a .4 hp/weight adjustment.

this allows you to run a C5Z at min weight, if you have any semblance of a healthy Z06, it would be hard to run it that light with 295s (no adjustment). Anything past 354 RWHP at min weight will blow 8.7 if you are running 295's. With the 275s, you can run about 20 hp more.

remember if you are down to 3118 you are taking .1 adjustment hit for being below 3200. you get .3 back with the 275s. nada with the 295s

@ 3118 lb essentially it's:
295's - 8.8:1
275's - 8.4:1

this is of course assuming your region is checking.

The C5Z is probably one of the few cars that's right on the line (most of them would be over) in bonestock trim running at min weight.

As the A6's age/wear the 275's make the car pretty loose when you are on the loud pedal, I like it because you really gotta drive it - and hard

SIK02SS

Driving on old/worn A6's really makes you a driver. You can't just put the car where you want anymore and stomp the throttle, you must learn to be smooth all around and take the clean line.

I don't have the experience in various tire sizes, but I do have experience on A/R 6's. Used R's can be as fast as used A's for 1-2 laps (according to my data on R's vs. another drivers times on used As that I was racing against).

With that said, I would go with the smaller A's if it were me, and run away from R6's regardless of who tells you they are good..unless it's an enduro (maybe..)

brian1234

I have an '02 Z06. I didn't think there was room for T1 bars AND A6 tires. This year the A6 are worth 13 points while last year they were worth 10. Here's my math so far:

The car starts with +7. sway bars are +2. A6 are +13, R6 are +10.
265 is -7, 275 is -4, 285 is -1, 295 is allowed, 305 is +1, 315 is +4.

So the winning formula is 295 R6 with sway bars (19 points)?
Or use stock sway bars and A6 tires, 275/17 front and 285/18 rear (or 285/18 all around). This is also 19 points.

That stuff about the .1, .2 hp for min weight stuff, I'm not familiar with that. Isn't that just for TTS, U, and R? I'm trying to stay in TTA.

SIK02SS

This is just my opinion, but THIS.

sperkins

You'll have to run 275 on all four corners to use an A6. That's a 9 point tire - leaves 3 to play with. The .4 adjustment is given back to you in power/weight ratio if you run 275 tires. Like Mark said, 275's = 8.4:1 at minimum weight.

brian1234

So use T1 sway bars and 275 A6? That adds up to 18, woo it works! So if I leave my bars alone (leave the T1 on there) then it's either 275 A6 or 295 R6. cool.

So the weight thing... I ran TTS last year because I had 315 tires to burn through. My car was weighed once and was 3360 with my fat *** sitting in it. Does that mean they'll give me some extra points for being overweight? So I can have more horsepower to keep my ratio at 8.7 to 1 is what you're saying? I think I understand that, but there's no way to increase my horsepower without adding points and getting bumped to TTS is there?

sperkins

Yep. If there were enough points to do it, you could run 500 RWHP, but you'd have to be 4,200lbs. Shave weight instead.

Kubs

Weight is felt everywhere on the track. HP is only for the straights.

96CollectorSport

Less weight will help your brakes, tires and wheel bearings all last longer, plus loosing weight is typically cheaper (to a point) than adding hp. Plus adding to cornering speed.

You're better off running the 275 vs the 285 because you will get a break of .4 on the hp and 4 mod points back.

What region are you running with?

brian1234

Great Lakes Region, Mid-Ohio is my home track. Last year I was on really old 315 R6 with T1 sway bars and my best time on the pro course was 1:36.5. I was in TTS and never came close to free tires. This year I'm going to do TTA and hopefully win the occasional free tire. Gotta love Hoosier for dangling that prize out there!!

So if these are the three options, everybody votes for #3?

#1, use 295 R6 with T1 sway bars (19 points).
#2, use 285 A6 with stock sway bars (19 points).
#3, use 275 A6 with T1 sway bars (18 points).

SIK02SS

I'd play around with #2 and #3...find for yourself which works best for you. I'd also throw #1 off the list all together and don't even consider it

96CollectorSport

Definatly look at #3, you have one point to play with that you could remove the cats or add a cold air intake.

Basically at 3360 you can make 386 rwhp with the 285's, you can make 404 rwhp with the 275's. Although I would get the weight down as much as possible, while still keeping the car streetable. (I'm assuming it's a street/track car.)

You may also play around with bars, you may like the smaller bars with the more narrow tires. This would open points up for shocks (+3).

Best of luck

Kubs

Your gonna have to fight Matt for some tires!

varkwso

Good a volunteer

brian1234

Who's Matt?

What shocks would you get for the +3?

drivinhard

my car is 100% legal at all times, unlike sperkins

some more TTA legal hardware showed up today