dencos

I have a new Z51 black/black being shipped next week.
I have been reading through all the wheel/tire threads and can't seem to find a solid answer to a couple of questions

I want a set of track wheels and tires in 18/19 (for tire choice)

1) will an 18x9 TSW Nurburgring on the front clear the z51 caliper?

2) will a 19x10.5 TSW Nurburgring on the rear with the +65 offset
take a 305/35/19 with out rubbing on the fender well? At +65 the
wheels stick out over 3/4" more than stock.

I see some TSW Nurburgring's with 285 stock tires & they look very close to the fender. I would like to lower the car a little bit and it looks like the 285's would rub if lowered.

I called a couple of vendors one told me they would work and another said they would not.

If any body has this combo installed please let me know and post some close up pictures of the tire clearance please.

Thanks for any help

Higgs Boson

mine rubbed with 285s

Elite275

My car is a base and not Z51, but I have these wheels on it with the 285's in back and haven't had any rubbing lowered all the way on stock bolts. After some power upgrades and the need to replace the tires, I'm also interested in what others have been able to put on the back with no rubbing.

leadville1

I have Interlagos TSW's 18/19 for the track and they clear the calipers no problem. I run slicks on the back that are 295/30/19 no rubbing at all.

Zajac

I guess I am a little confused, as one guy says TSWs rub with 285 tires and another says the do not rub with 305 tires. Both posters are knowledgeable guys. What are the facts, depending on tire choice of course?

I note that the rear C7 fender "lip" is .56" wide and the front fender lip is .16" wide so the rear has more potential fender rubbing problems. And as noted, the TSWs 19x10.5" width with a 65mm offset = about 3/4" (6.3mm+14mm) further out from stock so more potential for tire rubbing depending on tire selection. HRE FF01 wheels are 20x11 73mm offset and are close to the same problem (12.7mm+6mm).

I must be easily confused as I also don't get why aftermarket wheel mfgs do not simply use the exact front offset of 56mm and rear offset of 79mm for their wider wheels. A 1/2" wider wheel for a more aggressive 1/4" further out from stock and a 1" wider wheel for a more aggressive 1/2" further out from stock. Obviously, the aftermarket wheel mfgs of cast wheels have to choose an offset and width that pleases "most of the people most of the time".

Higher cost forged wheels usually allow a buyer to choose a desired offset and finish but that is usually $5,500+ a set.

I apologize for sort of hijacking this thread for a tire choice on TSWs.

Higgs Boson

Let me elaborate. TSW with 285s rubbed my passenger side rear lip with a passenger in the car and I hit almost any kind of dip or bump (didnt take much).

It is not like it just won't fit, it does, but visually, to me, it looks like it sticks out too much, I didn't like it.

I've been through about 5 sets of wheels now, plus waiting on my third set of Forgelines (305 on 11" +83mm) which should be about perfect.

It is my observation that going wider than stock and lower than +77mm offset can induce rubbing, your results may vary. I am comfortable pushing about 10mm outward with the rear tire/wheel and using offset to pull the rest of the width increase inwards. Up front there is more room to come out, I'd be comfortable with 12-15mm.

More than that either rubs or looks dumb.

leadville1

My wheels are not Nurburing's they are Interlagos so that may be a difference. I have done three track events with them and they work fantastic. Save money buy them vs. custom wheels. They are also really light compared to stock.

dencos

Just double checking, you have a z51 correct?
How much clearance on the front caliper do you have?

How much clearance rear tire to fender do you have?
Could you post a picture?
Do you think a 305 will fit with out rubbing?
I want to run Hankook rs3's there tire size goes from 275 to 305
thanks for the input

leadville1

Caliper clearance is better than stock that is not a problem at all with Interlago's can't comment on Nurburing different spoke design. I can't comment on the 305's I use 295 take off slicks from Pirelli from Ferrari Challenge.

dencos

No need apologize its all part of the equation.
There seems to be conflicting views on these wheels. I agree I don't know why they don't make these wheels with stock offsets, seems like they could sell these like hotcakes if they did. The clearances on the fender wells is so close (I guess, I haven't received my car yet to actually see) I wonder if it is manufacturing tolerance in the body panels?

Zajac

Higgs Boson, I had come up with an optimum +81mm for an 11"wide rear wheel so we are close in our thinking.

The tire selection for size and brand can make a big difference too.

Note the pic of the Michelin 275 Pilot SS (non ZP) on a 9.5 wheel width compared to the 305 Michelin Pilot SS (non ZP) on a 11" wide wheel. The 275 Michelin sidewall looks "normal". The sidewall rim protector on the Michelin 305 non ZP sticks way out from the rim and also from the sidewall which seems strange/unusual to me.

Higgs Boson

Yep, I will have Michelin PSS (nonRF) 305s on them so I'll get some good pics to compare with.

B Stead

The TSW wheels sit inward on a C5 and outward on a C6/C7. Most of the tuners that use the TSW on a C7 are using OEM tire size.

I don't normally recommend the Forgestar because they don't have the wheel correct rear wheel offset in 19 x 11 but here are wheels at about $500 each:

CF5
Front, 19 x 10, 56mm, Deep, 265/35-19 or 275/35-19
Rear, 20 x 11, 79mm, Semi, 305/30-20

F14
Front, 19 x 11, 55mm, Deep, 295/30-19 Pilot Sport Cup 2
Rear, 20 x 11, 79mm, Semi, 305/30-20 Pilot Sport Cup 2

The "Howey Industries" website has Forgestar ordering.


If the wheel offsets are more inward than 56mm front and 79mm rear that decreases vehicle track width. And a 5mm change in wheel offset can be felt, for instance, on an autocross course.


9.5" wide front wheels and 11" wide rear wheels can be found in the correct wheel offsets in the Cray 2014 line at about $400 each and in the Oz Superleggera III at about $900 each. The Superleggera front wheels are listed under the C5 and require a 3mm spacer to be 56mm while the rear wheels are listed under the C6. The Superleggera are sometimes in stock at TR
.

leadville1

Word of caution Cray's don't fit the Z51 Caliper in the 18" size the barrel is too small. You need to use TSW, the Interlagos is a great looking wheel by the way.

B Stead

Cray 2014 for the Z51:

Front, 19 x 9.5, 56mm, 275/30-19
Rear, 19 x 11, 73mm, 305/30-19

Front, 19 x 9.5, 56mm, 265/35-19 or 275/35-19
Rear, 20 x 11, 73mm, 305/30-20
.

B Stead

A 275 tire is spec on a 9.5" wide wheel and a 305 tire is spec on an 11" wide wheel.

The photos couldn't possibly be correct as labled. The 275 tire looks like it is stretched on a wider wheel
.

dencos

I like the idea of F&R 19" wheels but the difference F to R is 1.5%, stock is 5% would that mess with the computer?

Zajac

1. The few Cray wheels I have seen with provided offsets appear to be exactly the same widths and offsets as the TSW wheels.

2. A lot of C7 people seem to be very happy with the TSW widths and offsets so I may be in the minority along with a few others.

3. The track guys on the Corvette Roadrace forum think that 19" square setup is an odd duck setup with limited tire selection.

4. B. Stead: the angles of the photos may be a bit misleading. However, the 275/30/19 is NOT stretched on my 9.5" HRE wheel and the sidewall/rim protector is almost in line with the outer wheel lip. The 305/30/20 on my HRE 11" wide wheel looks odd mostly due to the very wide rim protector which sticks out 3/16" from the wheel lip. And yes, I have triple checked the tire sizes and HRE wheel sizes.

If the 305/30/20 tire and rim protector on the 11 wide wheel looked similar in profile to the 275/30/19 tire and rim protector on the 9.5 wheel, I would much more happy.

I do wonder if a Michelin 295/30/20 tire/rim protector would have a tire profile more similar to the 275/30/19 tire rather than the 305/30/20 tire/rim protector. Only way to know is to see the tires in person I guess.

B Stead

The OEM tires are four sizes difference between front and rear. There's no precisely required tire diameter because the runflats and non-runflats are a little different.

So a four tire size difference with these wider setups would be 265 front with 305 rear. I just avoided a 265/30-19 because of the short sidewall and began at 275/30-19. But it's still a very short front tire sidewall. The 19/20 setups of wide tires have a better front tire sidewall but less selection of tire in the rear tire.

In general, the 19/19 tire setups of wide tires are about 1/2" less tire diameter than OEM non-runflat while the 19/20 tire setups of wide tires are about 1/2" more tire diameter than OEM non-runflat. And then 1/2" in tire diameter is only 1/4" in tire radius.


Tire sidewall height is not included in the tire specs:

Sidewall height = (section-width times aspect-ratio) / 25.4


Also, look at the tire sizes and tire specs very carefully because I didn't pick out 1.5% tire diameter staggers
.

B Stead

Cray has a new 2014 line that includes 9.5" wide front wheels and 11" wide rear wheels. These front wheel offsets are 56mm and the rear wheel offsets are 73mm.

They also have wheels with the same widths and offsets as TSW.


This Oz wheel is often in stock at Tire Rack at about $900 each:

http://www.ozracing.com/car_wheels_v...GED/25480.aspx

The 18 x 9.5 and 19 x 9.5 59mm fronts are listed under the C5 while the 19 x 11 and 20 x 11 75mm rears are listed under the C6. Then a 59mm front wheel with a 3mm spacer is like 56mm.

What's the catch ? It's a little heavy and it's a real three-piece wheel that requires sealing
.