Here we go again... l apparently have some very odd ball tire sizes on my 03 Z06. when l purchased this Z a few weeks back, it had brand new wheel/tire package on it consisting of chrome deep dish aftermarket wheels, not sure the brand but this is them right here
https://www.ebay.com/itm/Chrome-C5-D...E/123140190784. And l gues look quite good if you are into chrome,
which l am not. The tire size is 305/30/18 on the rear and 255/40/17 in the front. This set up didnt look too bad (other than the fact the prior owner had this car WAAAAY to low. l was fortunate enough to get the full set of factory Speedlines with this car which l had powder coated black. l transferred the rear 305's to the 18's and l bought some wider tires for the
front as l didnt want that skinny of a tire up front with a 305 in the rear. So l bought a set of Falcon 275/40/17 and had them mounted. And there was my mistake. l had no idea the
height difference between the 255/40/17's the car came with compared to my new Falcons. The car looks so damn stupid now as the front is taller than the rear .. l have found
no good permanent solution to this as the actual tire I need for this 275/35/17 which doesnt exist. l actually found a NOS set of Bridgestone Expedia S01 shipped to my door for $275.
Now this will work for now but then what? l want to run the 10.5 squared. l know this is done all the time. l also know that the 305's l currently have on the rear are also an anomaly and are super hard to find out in the wild. This car will be a daily when finally complete, will only see actual tract time a few times a year but will often be canyon driving as l am lucky
enough to live in an area with a plethora of fast fun canyons to choose from. So l was thinking maybe a 295/35/18 all around? My other dilemma is this, is there any use for the factory
front Speedlines as l will now have a full set of 4 ( l am able to purchase a full set of the factory Speedlines for cheaper than just 2 rear 18's ) l have 2 of the front 17's that are powder coated black with the aforementioned 275/40/17's on them, all brand new. Would these even be worth trying to sell? Does anybody ever run 4 of these? (dumb question l know) l will
include some pics of the chrome wheels with the tires on the front and the before and after pics of the Z. Still looks better on black even though its sitting higher in the front

 

A lot of people run a square wheel setup.

I think it would be a helluva a lot easier and cheaper to just put the 255s on the front which is the size many run when they don't like the look of a 275 on the front.

Another thing people often overlook is that not all tires are created equally for their given size. Different brands and model lines can vary A LOT in physical size even though they carry the same tire size on the sidewall. So you could fine a fatter 255 or a shorter 275. Takes a lot of research though on manufacturer websites.

 

Good point Mr Black and I myself have thought about doing this as well. The reason I didn't is I don't want such a small tire on front (255) vs the massive (305) tire out back. This will surely encourage push when entering a corner hard at speed

 

What brand are those 305/30/18's, R Jay? Tirerack and Discount Tire do not show anyone making that particular size. A 275/40/17 is 25.7" tall and a 305/30/18 (if such a size exists) would be approximately 25" tall or so.
Running a taller tire on the front can cause AH/TC issues.

 

They are some off brand called Atlas and the model is Force. That's what was on the car when I got it. I did a little research and I guess they are pretty popular with the drift crowd. Maybe cuz they are cheap? Not sure but I kept them because they are brand new

 

Hmmm I just saw the Extra Load weight rating. I personally wouldn't want that on a C5. That is generally what is used on SUVs

Not saying this to bust your ***** but worrying about the handling characteristics of having a 255 up front with those weird china tires on that back seems kinda bass ackwards?

 

Yes that is one of my concerns. That small of a tire up front with a 305 out back, regardless of the brand, is not good. I wonder what kinda SUV runs that wide and low profile of a tire . I plan on running I think 295/35/18's all around eventually which will open up my tire options considerably

 

If you think a 255/305 is too wide a gap, guess my 265/325 combo wouldn't work for you, either. lol Strange, it works fine on my street car.

Just curious but what makes you think a 295/35/18 front is the right size?

 

When l had my 04 Z06 about 10 years ago now when l ran the stock size 295/265 set up (l think at the time l had on Michelin) l would always push when going hard into corners. When l put a 285 up front it pushed much less. l fear the same situation would present itself now, if not be exacerbated by having 305's out back with a much narrower tire up front. l honestly dont know
how your car doesnt push with that set up. You mention it is your street car, do you ever track/canyon drive that set up? Or is it just to cruise on? lf thats the case l 100% agree with you and
l would have no issues whatsoever using that setup

 

You should also look at the ability of the tire to grip the pavement. A normal 255/40x17 tire might push like a beast but a 200 TW tire like the Yokohama 052 in that size would hold the pavement much better than an ordinary street tire. The disadvantage is the 220+ per tire price. Also the 25.2" diameter is much closer to the rear tire diameter. Worst case it might cause an older rear tire to slide before the fronts broke loose. How good are the 052 Yok's, about 2 to 3 seconds faster on a 50 second autocross course compared to the Falkens

 

Agreed! l know the quality/compound of the tire has very much 2do with its grip. l am right now looking for a more, budget friendly option. l have actually done some more research on the questionable ' Atlas ' brand, specifically the Force model. l went over to the Mustang Forum where several members have actually tried them and posted their thoughts/results and overall they were very favorable. They pretty much all agreed on a few key things, one being these tires are absolutely horrible in the snow, but good in rain and actually grip fairly well and have been wearing very good as well. And the one thing they all agree on 100% is the price. You just cant beat the price of these tires. The 305/30/18 can be had for as little as $115 each! l think at this price point, and the favorable reviews i have read on them so far, that low entry price is worth the risk. And since l live in SoCal and my car will never see snow and rarely any rain, all the better!

 

If you want to avoid all of this hassle, switch to a squared setup with a wider front wheel. This would accommodate more sizing and allow for proper fitment of a wider tire.

 

Yes, this is actually exactly what l am going to end up doing. l am on the hunt for 2 factory 10.5 rears to go with a square set up in the very near future.

 

295/35/18 is the factory rear size. Unfortunately selection in this size blows. Might consider 285/35 or a 305/35 if it's a thing.

 

This is true so I think I will actually try (even tho I know it's not ideal) going with 305/30/18 square since I already have 2 rears in that size currently.