[glamcem]

Originally Posted by cdb95z28

Alright, with the discussion moving onto a non-square setup, lets add a 325 on the rear with a 305 up front, just like the 2018 ZL1 1LE.
Using a Gen 5 Z/28 rear wheel, 19x11.5 ET32. You could fit a 325 on an 11" wheel also. Running the #s show that on the Z/28 rear wheel the entire assembly moves out 21mm and maintains darn near the same inside clearance, within 1mm.

Attachment 857505

That is correct, in my case it would be about 28mm farther out compared to OEM. No suspension clearance issue (in fact 8mm more clearance on the inside). It might be still possible with some fender flares.

[V1LE8R]

Originally Posted by cdb95z28

Alright, with the discussion moving onto a non-square setup, lets add a 325 on the rear with a 305 up front, just like the 2018 ZL1 1LE.
Using a Gen 5 Z/28 rear wheel, 19x11.5 ET32. You could fit a 325 on an 11" wheel also. Running the #s show that on the Z/28 rear wheel the entire assembly moves out 21mm and maintains darn near the same inside clearance, within 1mm.

Attachment 857505

Steamroller status. I'll get a part time job driving over new asphalt with those tires.

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[glamcem]

Originally Posted by V1LE8R

Steamroller status. I'll get a part time job driving over new asphalt with those tires.

Sent from my SAMSUNG-SM-G935A using Tapatalk

How did you jack up the car if you don't mind me asking?
mag pucks?

[cdb95z28]

Originally Posted by glamcem

That is correct, in my case it would be about 28mm farther out compared to OEM. No suspension clearance issue (in fact 8mm more clearance on the inside). It might be still possible with some fender flares.

[Dirtdog]

Originally Posted by BradfordCamaro

Stick the 10's on the back. Done.
There is your square setup

And think of the weight savings!

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[1LE caSSper]

As obsessed as you all seem with adding rubber/ rotation mass to a car that already is "over gripped" keep in mind our exact wheel & tires oem are from the 150 lb heavier 200mph ZL1... where is the idea that OUR 200 short horsepower & lighter car needs more grip/traction ?????

Why even add 20mm of Tire to a car that already can't out due & over use its oem 305 rubber. I've yet to hear a hint of complaint from ANY online review wanting more grip, there's not even complaints from the ZL1.... until you touch 700hp you need not be worried about negligible differences in Tire width when that's this cars STRONGEST feature not weakest. Specifically speaking track time that SQ 315-325 just isn't practical yet. Adding 10 20 or 30 mm of Tire to each wheel [2 or 3 lb of Tire- rotational mass] to a car that already can not out drive what it already comes with sounds like a waste. And enjoy sourcing & paying for some 325s & 315... the tire selection is unbelievably limited just to start. I'll never pay 500$ for a 100 or 80 treadwear Tire lol good joke.

The more Tire always better stigma isn't 100% across the board, most of the time yes but in this case no. You all seem to want to go faster... faster how? Lap times or drag times..?

Tire width shouldn't be on ego and bragging rights. Faster lap times would best come dropping rotational mass,
Want a SQUARE track setup to go faster & more grip.? Nobody has thought about a 19x9.5 wheel @ 20lbs front & rear with r-compound / slicks 285s @ 28lbs each? VS oem that hypothetical setup drops ~ 40lbs off wheels & tires alone...........

***More grip, cheaper Tire prices , more track days faster lap times better acceleration less stress on suspension better braking......

Me personally going to test fit my 19x10.5 tsw interlagos 27 offset in front,
Everyone here wants square then that's the way to go at least for me 10.5 wide will fit most 305 tires if the manufacturer gives the thumbs up for it.
- saving weight, adding grip. Adding driver confidence, that's how you drop lap times

[1LE caSSper]

And don't forget please the understeer oversteer argument is missing 1 point.

It'snot about being smarter or more clever than engineers tuning & designing cars . They need to COMPROMISE

Why do most high end "Sport cars" in our class come with staggered oem setups? No understeer does not equal balance.. it's not the cheapest route nor most practical, hence why economy cars always use square setups.

We forget here understeer is SAFER. Think to ourselves now would you trust you're wife [not being sexist] learning to drive stick or 19 year old son in a car prone to kick out & spin <square setup> vs more likely to plow thru a corner at the limit very predictably?

All Porsche, m3, m4, corvette, other track oriented cars come staggered always have.. remember manufacturers are much more informed and better R&D than us all here COMBINED lol......

Why would Chevy leave a 30lbs AC unit in the car why would they elect to leave 30lb in rear seats in car, some people think it's a pure TRACK car it's not, we're as close as it gets nowadays but far off still. Cars need to appease 99% of people <somehow> not the 1 percent performance junkies like us
A staggered wheel setup is much easier to tame on any car & platform, it forces drivers to find the perfect apex for the best Lap time and drive THROUGH the understeer my instructors have called it. Best for most people, average drivers & predictability at the limit.

Most [every] pro race team I know someone associated with or around seems to run square setups. before I was more experienced I always wondered why? If oem has cars "perfectly tuned" for oem staggered setups like my e46 & e92 M3 days. When it comes to pure and lowest lap time consistency & advanced driver levels square is best. When you can power OUT of a corner with the rear tires at the limit before the fonts vs. powering THROUGH a corner held back by your front staggered setup at the limit - lap times are quicker with square if the driver can manage

Manufactures do EVERYTHING for a reason

[glamcem]

Not true at all see below for my responses

Originally Posted by 1LE caSSper

As obsessed as you all seem with adding rubber/ rotation mass to a car that already is "over gripped" keep in mind our exact wheel & tires oem are from the 150 lb heavier 200mph ZL1... where is the idea that OUR 200 short horsepower & lighter car needs more grip/traction ?????

Answer is easy mechanical grip you never get enough of it.
First of all, there is no such a thing like "over gripped" or "over cooled brakes" at track environment these are just common misconceptions that's been proven to be false many times. Just imagine how the ZL1 could improve its lap times by going with wider tires ..oh wait, GM already did that with introducing ZL1 1LE

Why even add 20mm of Tire to a car that already can't out due & over use its oem 305 rubber. I've yet to hear a hint of complaint from ANY online review wanting more grip, there's not even complaints from the ZL1.... until you touch 700hp you need not be worried about negligible differences in Tire width when that's this cars STRONGEST feature not weakest. Specifically speaking track time that SQ 315-325 just isn't practical yet. Adding 10 20 or 30 mm of Tire to each wheel [2 or 3 lb of Tire- rotational mass] to a car that already can not out drive what it already comes with sounds like a waste. And enjoy sourcing & paying for some 325s & 315... the tire selection is unbelievably limited just to start. I'll never pay 500$ for a 100 or 80 treadwear Tire lol good joke.

not true also, 305/30/20 and 325/30/19 tires weigh the same but going with 19" wheels has its benefits such as dropping the wheel weight about 7 lbs on each corner.. again 7lbs ..that's YUUUGE

The more Tire always better stigma isn't 100% across the board, most of the time yes but in this case no. You all seem to want to go faster... faster how? Lap times or drag times..?

Tire width shouldn't be on ego and bragging rights. Faster lap times would best come dropping rotational mass,
Want a SQUARE track setup to go faster & more grip.? Nobody has thought about a 19x9.5 wheel @ 20lbs front & rear with r-compound / slicks 285s @ 28lbs each? VS oem that hypothetical setup drops ~ 40lbs off wheels & tires alone...........

Not true also. It's apples to bananas, of course if you go with a different compound tires you may get better results than the slightly wider tires in different category. For the sake of an accurate comparison, you should consider all else being equal; meaning, same driver, same compound, same conditions ..etc . and guess what my friends and I did that already and all the track junkies that I had a chat with told me the same thing. It would not be a case for a 160 hp Miata since it may be hard to reach the ideal tire temps easily but not a case for a 3700 lbs with 450hp for sure where you can easily overheat which would also increase the amount of the consumables. It would defeat the purpose of saving money also.

Going with only 7% wider tires wouldn't change much.

Of course, 285 Hoosiers will more than likely be faster than 305 street tires no surprise there, now just imagine how the lap times delta would be between 305 street tires and lighter 325 R comps

***More grip, cheaper Tire prices , more track days faster lap times better acceleration less stress on suspension better braking......

I am totally with you on that and that;s the reason why I will be getting 325/30/19 NT01s since they only cost about $380

Me personally going to test fit my 19x10.5 tsw interlagos 27 offset in front,
Everyone here wants square then that's the way to go at least for me 10.5 wide will fit most 305 tires if the manufacturer gives the thumbs up for it.
- saving weight, adding grip. Adding driver confidence, that's how you drop lap times

Good luck fitting those wheels up front on stock suspension :/ have you read the entire thread and seen the pictures of the clearances? It's been discussed in this thread. You are trying to put the wheels almost 20 mm closer to the suspension when there is only about 10-12mm clearance on the OEM wheels. Without putting some big spacers it shouldn't work. Would you be happy running them with 15mm spacers on lapping day? I know I wouldn't

[glamcem]

Originally Posted by 1LE caSSper

Most [every] pro race team I know someone associated with or around seems to run square setups. before I was more experienced I always wondered why? If oem has cars "perfectly tuned" for oem staggered setups like my e46 & e92 M3 days. When it comes to pure and lowest lap time consistency & advanced driver levels square is best. When you can power OUT of a corner with the rear tires at the limit before the fonts vs. powering THROUGH a corner held back by your front staggered setup at the limit - lap times are quicker with square if the driver can manage

Manufactures do EVERYTHING for a reason

So there you go the reason why I wanted to go with 19" wheels as track set (for the street OEMs will be just fine). Like I said earlier, I will try to fit 325s on my second set (after Trofeo Rs) I had a chat with some Z28 owners at my local track/club events and they were running 325 or 315s square setup on their cars and they were happy with the outcome

[cdb95z28]

I looked around but could not find this: the front and rear "tread widths" of the '17 1LE. Tread width being an on car measurement from the outer side wall of the left tire over to the outer side wall of the right tire. Could any of you guys measure this? Looking for an untouched OE 1LE alignment. If you lay, say a 4 foot level or straight edge about 2.5" to 2.75" off the ground, so the level/straightedge can rest evenly against the tire. You'll need another straightedge for the other tire, and a buddy, wife or child to help. Run the tape measure from one side to the other, measuring from the inside edge of the straightedge to the other inside edge. Toe plays into it, so take a measurement from the leading edge and the trailing edge of the tire, add them together then divide by 2. Can someone do this at the front and the rear? Thanks

Something like this:

[cdb95z28]

It appears GM may have taken into account the use of 19" wheels with the 1LE or making more room for additional camber

2016 SS


2017 1LE

[MatthewAMEL]

Originally Posted by cdb95z28

It appears GM may have taken into account the use of 19" wheels with the 1LE or making more room for additional camber

YHGTBSM if you think that is enough room for suspension travel.

[cdb95z28]

Explain to me your comment. Every single part in that picture moves up and down as one unit.

[cdb95z28]

The only interference would be when the camber is adjusted inward, creating a tire/wheel to strut contact. You are acting as though this would escape some of us. The post clearly shows a difference from one component to the other.