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The new Zee comes with 12" wide rim, so putting a 335/30/19 on the rim will be no problem. Right now no one makes a 335/30/19 tire . There are 345/30/19 and 355/25/19 tires available which will also fit on a 12" wide rim. Whether they will fit without tubbing only time will tell. IMO other manufactures will setup with tires in the 325/30/19 sizes.
 

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For the track I recommend:

Hoosier A/R3S05 305/30x18 on 10.5x18" with +0.25" offset Front

Hoosier A/R3S05 335/30x18 on 12x18" with +0.25" offset Rear
 

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A couple of questions:
  1. Wouldn't that lower it in the rear much more than the front? I noticed Hoosier marks both those tires as a 25.6" OD.
  2. How do those offsets compare to stock? Wouldn't you need more postive offset to keep the tires under the fender
  3. Presumably those sizes are for DEs. However, would they require a second car to carry them since the C6 can't tow a trailer? Is there a tire you could drive to the track like a Corsa or Pilot Sport Cup?
David
 

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David,

1. Yes, slightly, if you didn't do an alignment, corner weight, lowering and ride height adjustment. But I am going to be doing all that for the track anyways. I will be setting the car up and keeping a 1/2" rake with the race wheels & tires ON which only increases when I put the street tires back on. ( The added benefit is that the smaller OD rear tire helps the final gear ratio and increases acceleration)

2. The offsets compare with stock as stated, "+0.25" " ie. the offset IS positive (+) 1/4" (wider at each wheel). This offset is the maximum allowed in SCCA stock classes. It is built into the wheels, so is readily available in CCW, Kodiak & Circle Wheels. It allows more inside clearance. It also so happens to correct the scrub radius back to ZERO on a lowered car.

A more positive offset as you suggest would push the wheel out. You may be confusing "offset" with "backset". These wheels have the same backset as stock.

3. As I said in my post "for the track" so yes, it implies DE's as well as other non-stock competition such as Solo II, Pro Solo, Solo I Time Trials. I do NOT recommend using the same tires on the street as you do for the track. I recommend getting a seperate set of race wheels and tires.

You CAN trailer a small tire or track trailer with the C5/C6. John Ames, one of the top national drivers travels to races in Fla, Mich, Ind, Kan, Ca, Utah & Texas with his Z06 towing a small tire trailer with 2 sets of tires, his "slicks" and his "rains".

I have also seen the hitch used to support a converted Aluminum "game carrier".

You also have the choice of trailering with a nice Aluminum open or enclosed car hauler & tow vehicle
 

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Nice answer. Some followups:
  1. I believe SCCA stock rules require stock OD and width wheels (I believe you are allowed 1/4" on the width). Wouldn't 18" OD rears move you to a Street Prepared or modified class? Is there a stock class solution?
  2. The C5s, with their side mount mufflers, have trailer hitches available. After looking, I haven't seen one for any C6 with its center mount mufflers. Have you found one?
I definitely agree, you shouldn't run your race tires on the street. And the Hoosier or V710s aren't streetable anyway. You could even have a separate set of shocks for the track, and if using coil overs, with separate springs, different ride height, and different cross weight.

David
 

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DJ,

You obviously have much more knowledge than most of us.

Question, please: If I am not planning to run my 06 Z on the track, in regards to your comment about scrub radius being altered on lowered cars, would lowering my it 1/2" front and rear (for appearance) cause wear, handling or other problems?

I am going to have it re-aligned immediately afterwards.

Thanks much!
 

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toyo ra-1's great tire. can be driven on the street grip like glue, wear like stone.
335/30ZR18
305/35R18
 

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1.) There currently is NOT a stock class solution for the C6 Z06 wheels & tires for a number of reasons:
- mainly, tire manufacturers have not produced any 19" DOT racing tires or R tires to date. (it's too early)
- The C6 Z06 isn't legal for SCCA competition events until after January 1, 2006.
- tire manufacturers have until April 30, 2006 to submit tires for approval & inclusion in the 2006 racing season
- tire manufacturers are producing tires now for the season end 2005 Championships in SCCA Pro Solo, National Tour, Solo I Time Trials (if there is one), T1, GT1, WC, ALMS which take place in September and October. They will worry about next year and the C6 Z06 fitment after that (maybe).

The important point is that all of those reasons and solutions are moot anyways since the SCCA has tenatively addressed this issue with a preliminary 2006 C6 Z06 ban in stock class(es). So it automatically is eliminated in T1 and moves up to ASP In Solo I, Solo II and Pro Solo. This of course could all change by January but probably will not. Tenatively they intend to review stock inclusion in T1 and Solo classes for 2007.

So the direct answer to the question is YES the 18" rear wheels will move the C6 Z06 to ASP class, but it has already been moved there; at least for 2006, wether or not you run stock sized 19" wheels or not, (which you won't be able to find 19" race rubber for). That's why I recommend the 18" wheels & tires as they are readily available and are legal in ASP and above where wheel & tire size is unrestricted.

2.) I won't be and wouldn't be running the C6 Z06 stock mufflers, even in stock class(es) where CAT back mods are allowed. They are too heavy and too restrictive below 3,000 RPM. I would look for a Corsa "Z" Series Titanium Race System type CAT back to replace it. So a hitch will be available. I am also sure that DeLan and Draw Tite will engineer a hitch for the car to be used with the stock mufflers as soon as possible.

Lowering 1/2" will not disturbe the Zero scrub radius. You should have it the alignment checked after lowering and settling.
 

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What are the stock wheel sizes for the new Z06? I think 19 inch bling rims and corresponding bling cross drilled rotors were a stupid decision.
 

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The Toyo's 305/35 IS too tall and has the wrong aspect ratio for the front

The 275/335 F/R combo would NOT balance the car correctly to neutral and too much static, initial and mid corner undesteer would remain. Although enough power is on board to correct the understeer and rotate the car during corner exit it could not be used effectively on corner turn in and mid corner. Trail braking would be "fun" with a great deal of modulation in both steering and braking...your plate would be full and you would be very "busy" with this combination.

Stock sizes are:
275/35ZR18 on 18x9.5" Front
325/30ZR19 on 19x12" Rear
plus
Goodyear F1 Supercar Extended Mobility Tire with wheel/tire pressure sensors.

A great set for the street and highway. But I would get rid of all the bling for the track.

The jury's out on the brake rotors as yet. We'll see soon enouugh if the metallurgy is up to par, if the cross drilled holes are post-cast-drilled or cast-in-place and how soon they warp and crack.

It will also be interesting to see, if any problems exsist, if they are aminable to Cryogenic/Heat treating, Thermal and Vibrational Stress Relief, Extrude Honing and coatings. Will these be street only, disposable race rotors or better than the C5 Z06. What can we expect that with a $65,800 base price ??
 

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DJWorm said:
2.) I won't be and wouldn't be running the C6 Z06 stock mufflers, even in stock class(es) where CAT back mods are allowed. They are too heavy and too restrictive below 3,000 RPM. I would look for a Corsa "Z" Series Titanium Race System type CAT back to replace it. So a hitch will be available. I am also sure that DeLan and Draw Tite will engineer a hitch for the car to be used with the stock mufflers as soon as possible.
The C6 has been out for 1 year, and to the best of my knowledge, no hitch. Needing quite in the neighborhood and not seeking regional or national Solo II titles, I will probably stick with the stock (quiet) setup. However, all of the setups should block a C5-style hitch.
 

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- mainly, tire manufacturers have not produced any 19" DOT racing tires or R tires to date. (it's too early)
DJ... assume you mean 19" racing tires that fit the Z.

As Michelin Pilot Sport Cup and P-Zero Corsa do come in 19".
 
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