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Discussion Starter #1
I have pretty much decided to purchase/order an ATS 3.6L Premium edition as it has most of the
items/options I want.

17" wheels are not available and I have heard that the 18" wheels ride harsher and are noisier than the 17".

Does anyone have any experience with both?

Thanks in advance for any info.
 

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ATS 2.0T
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108 Posts
I actually work at a Cadillac dealership, and I will be honest there isn't a whole lot of difference between them. I enjoy the ATS so much that I leased one myself. The bottom line is that with the 18" wheels the vehicle performs the way that it was meant to, though the 19" wheels are a no go on the ride quality. If you decided that you wanted get rid of the 18s I'm sure someone would be willing to swap you out without any problems.
 

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2013 ATS Performance 2.0T M6, 2016 Mustang GT Performance Pack, M6
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While sidewall height is a factor I wouldn't be surprised if run-flat wasn't a bigger factor in ride. I think the 17" are all conventional tires and all 18" tires are run-flats. Its all about effective spring rate. The sidewalls and the actual springs are the biggest components of effective spring rate. So between a shorter sidewall and the extra stiffness of run-flat., I would expect a noticeable difference in ride quality UNLESS softer springs are put on cars ordered with 18" and I highly doubt that.

I'd suggest test driving each (a base model for the 17") on the worst roads you frequent unless you are ordering the magnetic shocks which would make the comparison apples and oranges. Ultimately what feels best to you is what matters. No tech spec can decide that.
 

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90.5 Allante, 02 Deville, 13 ATS 2.0t
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The 17's are run flat as well. the 17's look small on the ATS because the wheel wells are so big! The fact that they are all season has a big impact on handling. I went with the 17's because I will be doing some winter driving. I will get a spare set of 18's with real tires for summer and track use.
 

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BMW 750li, MB S550, Bentley spur and Escalade platinum
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268 Posts
i have run both 17 and 18 and even the 19 inc option...
but..in my opinion..go BIG or go Home...:)

the 18 run so firm and much more with 19...but...it is a hi performance sport car...so it better like the way it is... or Buy an old Grand Pa Buick...
 

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2013 ATS Performance 2.0T M6, 2016 Mustang GT Performance Pack, M6
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On the standard trim the 2.0 turbo does have run flats only the standard 2.5 doesn't.
He's buying a Premium. He's concerned about the stiffness of 18" wheel/tires. Someone mentioned swapping (you can't order them) 17" tires if he wanted softer. Again, the BASE 17" tire/wheels would be the softest because they are not run-flat.

Edit: Now I understandd your post. When I said base I meant the base engine and trim, not the just base trim (called Standard). I definelty should have said 2.5 Sandard instead of base because base is ambiguous in this context. Sorry.
 

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2017 ATS-V Sedan, Vector Blue/Black, 6MT
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BTW, the Premium with MRC (i.e. no AWD) rides better overall even with the 18s, because of the MRC. If you drive the Luxury or Performance 17s vs 18s back to back, I doubt that you will notice much difference in the ride (they all have run-flats). At least, I didn't. Maybe it's the ultralight weight forged 18s, but they really don't extract much of a ride penalty at all. The MRC seems to be more compliant over sharp bumps, though still extremely well controlled. None of these cars have any float at all. I've never driven a base 2.5 without the run-flats, though.
 

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ATS 3.6L Luxury
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235 Posts
i have run both 17 and 18 and even the 19 inc option...
but..in my opinion..go BIG or go Home...:)

the 18 run so firm and much more with 19...but...it is a hi performance sport car...so it better like the way it is... or Buy an old Grand Pa Buick...
I would rethink that. I have driven 17" and 18" on different cars, and the larger wheels reduce ride comfort and their increased heft (unsprung weight) reduces hp efficiency and makes the shocks work harder. The larger wheels are almost always about looks. They simply look better, and if you have extra hp, well, who cares?

But if it is comfort that you are after, the smaller 17" wheels are normally the way to go. However, the run-flats are stiffer than normal 17", due to their stiffened side walls. That is probably also why the perception between the 17" and 18" wheels is the same - they are both stiff wheels. If you push the car, perhaps the 17" are faster of the line and the 18" has higher cornering ability - but we are talking marginal differences here, imo.

Still, I would not relegate the 17" to Pa Buick territory. They may in fact be faster.

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I have pretty much decided to purchase/order an ATS 3.6L Premium edition as it has most of the
items/options I want.

17" wheels are not available and I have heard that the 18" wheels ride harsher and are noisier than the 17".

Does anyone have any experience with both?

Thanks in advance for any info.
Ask the dealer to have you try out both. I am sure that you will want to go with the 18", for looks, but the harshness and noise levels is something you should judge for yourself, as it is very personal.

I would expect the MRC being tuned for the 18", and that mounting 17" would require an (unavailable?) adjustment to their settings. It is not a Cadillac decision, imo, it is a market segment standard.

I have driven 17" and 18" on different car models back to back, and the difference was pretty noticable. On the ATS it is much less so. Maybe the side walls, maybe the suspension, hard to tell.

I have the 17" on my model (Lux), and find their noise and harshness acceptable. But grip wise, I feel sometimes that I have to baby them, and wonder whether the 18" would be better under those same circumstances. Understeer, so it is easy to correct. And my vehicle already was set up with equal tire pressure on all fours, even thought the door sticker suggest higher pressure in the rear (which would make it worse).
 

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any noise or harshness from increasing to 18" wheels is due to the tires. I personally think the 17" wheels look WAY too small on the ATS and the 18"s actually look a little small as well. 19" would be the best look but that's not an option, at least not from the factory.

I'd get the 18" setup and if you're unhappy with the ride/noise, buy some new quieter tires. I'm sure they're you'll find some that are a big improvement
 
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