Wide 18 Question

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I am new to aftermarket wheels and I am wondering why lower offset (<45) 18x9.5 inch wheels seem to be popular versus the OEM 20s. Is for stance and/or for a larger contact patch? Racing? Don't the tires stick way out, kick up more debris and cause more damage to the lower part of the car? I had discounted this size for my DD use this winter, but I am wondering if I am missing something.
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Driveitlikeuboughtit

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It's a combination of things. Stock is 30 profile. A lot of users report 40 profile leads to floatiness. If you want a 35 profile tire on a 18 inch wheel, you need a 265 wide tire to get a reasonable speedo error (<2%). If you want to comfortably fit a 265 wide tire, you need at least a 9.5" wheel. If you need a 9.5" wheel, you technically need a 47.5mm offset to keep the same relative geometry. That happens to coincide with a lot of 45mm offset wheels already on the market. The extra wide tire is gravy - internet research leads you to believe that can be a positive or negative, but I know successful racers on here are pushing for wider and wider front tire/wheel combos.

If I could have gotten something closer to stock offset/geometry in 18" with stock width, I would have. But I don't think it really exists unless you spend a boatload.

They do stick out a bit more, but 45mm or more offset keeps it tucked under the wheel arches for an aggressive look to boot. They do kick up more debris, but mudflaps are a thing. And despite being wider, 265/35 R18 tires are generally cheaper considering performance than the stock tire size 245/30 R20.
 
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Thanks, for the answers. Still undecided but I have more to think about.
 

Night Fury

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It's a combination of things. Stock is 30 profile. A lot of users report 40 profile leads to floatiness. If you want a 35 profile tire on a 18 inch wheel, you need a 265 wide tire to get a reasonable speedo error (<2%). If you want to comfortably fit a 265 wide tire, you need at least a 9.5" wheel. If you need a 9.5" wheel, you technically need a 47.5mm offset to keep the same relative geometry. That happens to coincide with a lot of 45mm offset wheels already on the market. The extra wide tire is gravy - internet research leads you to believe that can be a positive or negative, but I know successful racers on here are pushing for wider and wider front tire/wheel combos.

If I could have gotten something closer to stock offset/geometry in 18" with stock width, I would have. But I don't think it really exists unless you spend a boatload.

They do stick out a bit more, but 45mm or more offset keeps it tucked under the wheel arches for an aggressive look to boot. They do kick up more debris, but mudflaps are a thing. And despite being wider, 265/35 R18 tires are generally cheaper considering performance than the stock tire size 245/30 R20.
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RS27

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@Driveitlikeuboughtit - Good info. In regards to your comment on 40 series as “floaty,” I assume you mean too tall a tire 40 series. Like a 255/40 18 or 265/40 18? Because (as you probably know) a 245/40 18 tire is nearly identical sidewall height to the 265/35 18. So that should not be “floaty” at all. Just as sharp as the 35. That profile (35 vs 40) is simply a percentage of width.
 


Driveitlikeuboughtit

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@Driveitlikeuboughtit - Good info. In regards to your comment on 40 series as “floaty,” I assume you mean too tall a tire 40 series. Like a 255/40 18 or 265/40 18? Because (as you probably know) a 245/40 18 tire is nearly identical sidewall height to the 265/35 18. So that should not be “floaty” at all. Just as sharp as the 35. That profile (35 vs 40) is simply a percentage of width.
Millimeters matter with profiles this thin, and I know for a fact that 265/35/18 is about 2-3% smaller in diameter than a 245/40/18. The wheels are the same diameter, the difference is in the sidewall profile. Also, the 265/35's are still floatier in feel than the stock tire size.

I have not personally driven a Type R with a 245/40/18 tire, but I have read other people's experience on this forum. One user specifically swapped from 245 40 to fatter 265 35 profile and found it much more enjoyable. I have driven one with 245/35/20's on stock rims, and it felt floatier than stock and the turn-in wasn't as sharp.
 
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apk

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I just put on 245/40 18s on this week. I reserve final judgement until they are broken in, but yes floaty seems to be accurate. I expected this and for a daily with bad roads, I am fine. I will update after 500 miles.
 

RS27

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^A 245/30 20 stock Conti should be sharper on turn in than a 245/40 which is (honestly) a pretty chubby tire. I wouldn’t consider that “low profile” at all. That’s why many do the 255/35 - 265/35 - 275/35 in 18’s.

I was just mentioning that in general going up 20 mm in width and dropping 5 in profile is about the same rolling diameter.

Of consideration is that 245/40 18 being used above is most likely not nearly as stiff as the OE Conti’s. The tire itself makes all the difference. A RE-71 is going to be stiffer on turn in at 245/40 18 than say a Conti DWS 06 in the stock 20” size.

Good stuff this tire talk.
 

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I’m running 18 X 9.5 +44 CE28N SL with 275/35 Michelin Pilot Sport 4S.

No issues at all...

Honda Civic 10th gen Wide 18 Question A9C3CD8B-B2ED-462E-8FCF-186E6C624300
 

BABear70

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Many have gone lower with this setup and no rubbing either. Not worried at all.

I did my research before I went this wide... The key is having the right offset.

B. A.
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