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18” Square Setup Help

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Old May 19, 2025 | 07:03 AM
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Default 18” Square Setup Help

Hello! I just bought a set of Z06 wheels and tires. They’re all 275/35ZR18 wheels. I’d prefer if the sidewall ratio in the back was a little beefier than the fronts just for a cleaner look. Is this something I should’ve bought a staggered setup for? What tire size can I run to not wack out the speedometer? I originally thought (with lack of experience) I could just throw a 295/45/18 in the back and call it good… is this even possible haha? Thanks.
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Old May 19, 2025 | 10:37 AM
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Originally Posted by ls1mc5hane
Hello! I just bought a set of Z06 wheels and tires. They’re all 275/35ZR18 wheels. I’d prefer if the sidewall ratio in the back was a little beefier than the fronts just for a cleaner look. Is this something I should’ve bought a staggered setup for? What tire size can I run to not wack out the speedometer? I originally thought (with lack of experience) I could just throw a 295/45/18 in the back and call it good… is this even possible haha? Thanks.
275/35/18 wheels?? First, was there a reason to buy the wheels you did? You do realize the fronts are going to poke, right? Depending on the car's primary useage, you could go with either 295/35/18's, 295/40/18's, or 305/35/18's on the rear.
275/35/18 = 25.6" diameter
295/35/18 = 26.1" diameter
295/40/18 = 27.3" diameter (close to max diameter on a stock fender C5)
295/45/18 " 28.5" diameter (way too tall to fit)
305/35/18 = 26.4" diameter.
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Old May 19, 2025 | 06:52 PM
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Originally Posted by USAZR1
275/35/18 wheels?? First, was there a reason to buy the wheels you did? You do realize the fronts are going to poke, right? Depending on the car's primary useage, you could go with either 295/35/18's, 295/40/18's, or 305/35/18's on the rear.
275/35/18 = 25.6" diameter
295/35/18 = 26.1" diameter
295/40/18 = 27.3" diameter (close to max diameter on a stock fender C5)
295/45/18 " 28.5" diameter (way too tall to fit)
305/35/18 = 26.4" diameter.

Lol I bought a set of four Z06 wheels WITH tires on them for $500 I didn’t really care… They poke but they don't rub at max angle so I don't necessarily see the issue. Thanks for the info
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Old May 20, 2025 | 02:34 AM
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Mine came used with 9.5x18 10.5x18 275 35 18, 295 40 18 there is some rubbing wear on the fender liner but it's not symmetrical not sure what happened. No initial errors but there is a traction control warning after 10 miles I'm still investigating. I'm about to go back to 255/45/17 front too.
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Old May 20, 2025 | 12:11 PM
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Originally Posted by CFight
Mine came used with 9.5x18 10.5x18 275 35 18, 295 40 18 there is some rubbing wear on the fender liner but it's not symmetrical not sure what happened. No initial errors but there is a traction control warning after 10 miles I'm still investigating. I'm about to go back to 255/45/17 front too.

For sure! good to know. Since I have all four at 18x10.5 do you think I could swap down to a 255/35/18 setup in the front to void this issue? Im sure I could ratio the back to fit the fronts. I was recommended a 295-305 in the rears.
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Old May 20, 2025 | 02:36 PM
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Originally Posted by CFight
Mine came used with 9.5x18 10.5x18 275 35 18, 295 40 18 there is some rubbing wear on the fender liner but it's not symmetrical not sure what happened. No initial errors but there is a traction control warning after 10 miles I'm still investigating. I'm about to go back to 255/45/17 front too.
You posted your wheel diameter and widths but not the offsets. That's pretty important info. With the right offsets, your tire sizes should be fine.
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Old May 20, 2025 | 02:42 PM
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Originally Posted by ls1mc5hane
For sure! good to know. Since I have all four at 18x10.5 do you think I could swap down to a 255/35/18 setup in the front to void this issue? Im sure I could ratio the back to fit the fronts. I was recommended a 295-305 in the rears.
A 255/35/18 is really short at 25" tall and would be pretty stretched, on a 10.5" width wheel.
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Old May 20, 2025 | 10:17 PM
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Originally Posted by USAZR1
You posted your wheel diameter and widths but not the offsets. That's pretty important info. With the right offsets, your tire sizes should be fine.
They came on the car with no offsets recorded. they are zo6 rep style
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