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Running 18/19's with standard C6 tire and wheel sizes (I figured GM actually might actually know what they are doing) and moderate lowering to center up the wheels in the openings. Got them as a package from Tire Rack - jack up car, change wheels, "learn" TPMS sensors and you are done. Especially good if you get a deal - my rear wheels were only $119 on sale, and the fronts only $164 - drastically different to what some people are paying for so-called "brand name" wheels that don't look any better.
Pros: looks so much better. It really does, no excess "air" over the wheels.
Cons: none, in the real world. The unsprung weight is higher, but I am not in F1 so it's irrelevant.
Tires are Michelin Pilot A/S. Great tires. Even got me home in major snow a couple of times. Much, much better grip than my previous summer tires.
One thing you should realize is that nearly everything on production cars is a compromise between the engineers and the marketing people. The best performing wheel is always the lightest and smallest wheel that can fit over your brakes while being the correct width for your tire choice. I read that the engineers wanted 17" wheels in the rear for the C5, and the marketing people pushed for 18" because "it looks better."
Originally Posted by jjc508520
Just wondering why more people aren't using square setups - so tires can be swapped "front-to-rear?"
Traction control kicks in earlier than it normally would when driving near the limit. Some cars are very sensitive to square setups and traction control wouldn't behave well at all. There also seems to be no pattern to which cars are more sensitive than others.
Originally Posted by grampi50
There are A LOT more tires available in the 18/19 sizes vs the 17/18s...
Most performance tires worth getting are available in the 17 and 18 sizes anyways.
Food for thought - If you put wheel design/color aesthetics aside, the main reason the 18/19 combo seems more attractive IMO is b/c the C5 fender wells appear more full & that translates into a lower/sportier appearance. I have a C5Z - so I KNOW my 17/18" factory combo is going to be lighter than any 18/19 combo unless I wanna spend big big $$$, also Z06 suspension is already stiffer than a regular C5 + I have added bilstein sport shocks, stiffer sway bars/links, poly bushings etc. - AND I also have it lower between 3/4-1" on factory bolts. Reason I mention all that is, while 1" larger wheel/smaller sidewall doesn't sound like much of a diff, when you're already starting w/ a car w/ tighter suspension like the Z06 OR if you do plan on adding suspension mods or especially if you plan on lowering, all the negatives that go along w/ lowering/tightening the suspension will be exaggerated w/ the thinner sidewall/larger wheel setup.
That being said....my car lowered 3/4"-1" on the 17/18" stock wheels yields a similar look to a non-lowered C5 on 18/19" setup. Now - take both cars & add poly bushings, larger adjustable sways, & stiffer shocks.....well, take a guess which one will give a harsher ride & perform worse??
I would think VERY hard before spending the $$$$ on an 18/19 wheel/tire combo if you have longer term/bigger picture plans for the performance-mod wise. #1 - as others mentioned can add unsprung weight & hurt performance depending on setup (can also help too apparently - doubtful for any Z cars tho) & will ride rougher, but #2) its alot of coin to spend on what's mostly a purely aesthetic upgrade & results in higher long term costs too w/ replacement tires.
I opted to keep my stock Z06 wheels & powdercoat black b/c of what I stated above. I think if I were to switch up the wheel setup I would go w/ 18" all around and/or could potentially see swapping to different wheel setup if I added a brake kit that required more clearance - other than that, if you're more performance oriented than appearance I think $$$$ is much better spent elsewhere. That being said - if you're already satisfied where your car is from a power/performance standpoint & looking to freshen it up, there's not much else that'll make as big a difference as a wheel swap.
Yeah, 7 year old thread but might as show a picture of my 18" and 19" Ronal setup.
That looks perfect KBK. I am sure you have done it in some thread some where but can you walk us through your set up or point to a thread that does..........thanks.
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16'-'17-‘18-'19-'20-'21-'22-
'23-'24
Originally Posted by kzoo-z
That looks perfect KBK. I am sure you have done it in some thread some where but can you walk us through your set up or point to a thread that does..........thanks.
Big Thanks.
Not much to say for the exterior picture shown. It's just 18" 19" made in Germany Ronal rims (no longer made) on Michelin Super Sport tires. Car is lowered on stock bolts. I have a ton of mods to it though that can't be seen from this picture.
In the garage is/was my 98. I miss that car (905 HP) It was replaced by a black on black 99 (620 HP).
I ran with 18’s all the way around. Saved weight on the Toyo Proxes when I ditched the run flats. Then I paired it with Forgestar F14’s, comparable weight here from the polished OEM wheels. It looks 100x better once I had the LG coil overs installed and lowered. No ridiculous wheel gap and no tire poke. Exactly what I requested. My only gripe is the perfect fitment made for a odd rear tire size which is apparently only stocked on the west coast. Rides and looks awesome IMHO.
To start, some really smart people determined, with the complete redesign when the C5 came out, that a staggered setup would be best. I believe in the stagger. I’ve seen many who’ve gone to c6 wheels but still respect the stagger, and I think they look great. IMO a 19/20 setup is a bit too big. (Please remember I stated in MY opinion).
What I perceive as the problem of a square setup by both wheel and tire size is does one end up with too much tire in the front, or not enough tire in the rear? The car was designed for larger tires in the rear, and for looks alone I like it. I also don’t know of many other high performance cars that have total square setups.
Appearance wise I see lots of discussion about filling the wheel well. That’s fine, and I must admit that the c6 sizes do a better job of that.
However, because the rear is usually one size lower in profile than the front (40/35 for example) I have seen examples where the same size rim all around results in a lower profile tire in the rear, giving the appearance of a smaller tire back there, which is not proportionally pleasing to me.
Since ride quality is important to me, I chose to have 17/18 rims in Z06 sizes. Going to lower profiles with larger wheels usually reduces ride quality and increases harshness.
what offsets did you get on those rims? Looking at the exact same setup but unsure what offset I need to make sure they don’t stick out? Thanks
I went with the figment guide from TSW, compared the offset shown with stock(which I can’t recall now) on tiresize.com, and then discussed it with the wheel salesman from AutoAnything where I got them. The difference is minimal and there are NO issues at all. I think offsets would have to be extremely different from stock to cause problems.
So if you keep the overall height the same as OEM and use larger wheels the side wall is decreased and the ride comfort will suffer. Increase the overall height and your speedometer will be wacked inaccurate. Messing with different sizes will likely affect the traction control. Looks great in the driveway, garage or car show. When I was 17 years old that's the first thing I did to my car right before I made the exhaust loud. I wanted to be seen and heard appearing "special and different". Good luck! $$$$$
So if you keep the overall height the same as OEM and use larger wheels the side wall is decreased and the ride comfort will suffer. Increase the overall height and your speedometer will be wacked inaccurate. Messing with different sizes will likely affect the traction control. Looks great in the driveway, garage or car show. When I was 17 years old that's the first thing I did to my car right before I made the exhaust loud. I wanted to be seen and heard appearing "special and different". Good luck! $$$$$
Going to 18's & 19's with C6 tires sizes gives you a diameter increase of approx 1/2". If you recall freshman trig, that is approx 1.5" larger circumference..... which equates to roughly a 2% change .... so maybe 1.5 mph change in speedo reading at 75mph. No big deal. And it does not mess up traction control. Most speedos are a little 'fast' anyway. My speedo is now spot-on. As for ride, I couldn't tell any difference when going up +1 with Michelin on both. Sure it costs $ ... but I love the look. Well worth it for me.
I have Z06 sizes, so I have a 40/35 profile, base is 45/40. Thats the same front/rear profile for a base c6, so I don’t see much of a problem with ride harshness. However, going to a 30/25 profile would seem to be asking for a harder ride. I’ve seen too many c5’s with C6 wheels to find them objectionable, but aesthetically I find the very low profile tires to be unattractive, I would not go any bigger.
I originally had the stock diameters on the Goodyear OEM tires. When I went to 18" f&r ride got better because of having better tires. Now I am on 19" f&r with Michelins and the car rides the best. Probably because of even better tires. I am still running the original overall diameters, just have shorter sidewalls.
11-28-2018, 02:52 AM
