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Dealer found me a Acadia, but it has 19's. I don't love the look of them, hence I don't want to pay for them (wife thinks I am being silly). The dealer has offered to swap them out for a set of 18's off another acadia. As there has been multiple comments that the Acadia is tuned to the size wheels on it at the factory, I wonder what kind of impact on handling going from the 19s to 18s would be.
 

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If I remember correctly (and I know somebody will correct me if I'm wrong), The Acadia was tuned for the 18's. Both tires have essentially the same height. the 18 has 1 inch more rubber and the 19 has one inch more wheel. The consensus seems to be that the 18's ride a bit smoother (some say more than a bit). I believe I have read that they (18's) could be better in snow (because slightly narrower and more of an all weather tire). Don't think I have seen much on cornering ability or skidpad tests.
Except for the looks, I think the impact would be mostly positive if you switched. I would look at both sets of tires on Acadias. Since the both fill up the space the same way (well one has more rubber, the other a little more rim), you may not see that much a difference.
 

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cmg27 said:
Dealer found me a Acadia, but it has 19's. I don't love the look of them, hence I don't want to pay for them (wife thinks I am being silly). The dealer has offered to swap them out for a set of 18's off another acadia. As there has been multiple comments that the Acadia is tuned to the size wheels on it at the factory, I wonder what kind of impact on handling going from the 19s to 18s would be.
The GM guys on here would be better to hear from, but there is going to be a loss of some kind of quality. If the vehicle has a suspension tuned for 19" wheels, and you put 18" on it, something is going to be off.

I'd also be questioning whoever buys the other vehicle. Dealer should be upfront on the switchout.
 

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Lots of good technical discussion in the "18s vs 19s"[/color] topic. The following quotes pretty well sum it up.

acadia7j100001 said:
tire facts...18" are within a 1/4 inch of being the same overall diameter as the 19". 19's have less sidewall height than the 18's. Both are made by Goodyear. 18's are all season rated and 19's are "performance" rated. Actual performance is very similar with less than a foot difference in stopping distance. Maximum lateral acceleration (cornering power) is within .01g. Ride is slightly firmer with 19's but suspension tuning has been adjusted to minimize difference. Putting 19's on a vehicle that had 18's WILL result in a notice-ably stiffer ride.
acadia7j100001 said:
lots of good discussion here. Factory suspension tuning for the 19's is different from the 18's. So yes, it would be better to go from 19's to 20's. Shortly, there will be a 20" package available from GM parts. It will include specifically developed tires, wheels and different stabilizer bars to keep from significantly affecting the ride. If you're doing 20's on your own...ride will change more dramatically if you're starting from 18's than 19's. And yes...lots of time was spent with Goodyear on the 18's (not sure I'd say exorbitant...based on the great results!). We are very proud of the result...great ride, great handling, great stopping, great fuel economy and low noise...all from a "base" tire!
So going from a 18 to a 19 will result in a stiffer ride. The 19 suspension was softened a bit for the 19's (it sounds like). Thus not sure what going from a 19 to an 18 will bring. Probably a softer ride. But I agree with cmg27, the guy (or gal) buying the other vehicle could be getting screwed because they would be going from an 18 to a 19.
 

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I drove an Enclave with the 18s and an Acadia with the 19s back-to-back the other day. The difference is cornering grip is far more than 0.01. Maybe they meant 0.1, which is a large difference? I'll venture it's AT LEAST 0.05, which is still a lot.

Next question is whether you'll use this extra grip.

I reported earlier that the 18s have more grip on slick roads.

But I personally think the 19s look much better.

Unless the dealer is going to give you full credit for the extra cost of the 19s, I'd keep them.
 

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mkaresh said:
I drove an Enclave with the 18s and an Acadia with the 19s back-to-back the other day. The difference is cornering grip is far more than 0.01. Maybe they meant 0.1, which is a large difference? I'll venture it's AT LEAST 0.05, which is still a lot.

Next question is whether you'll use this extra grip.

I reported earlier that the 18s have more grip on slick roads.

But I personally think the 19s look much better.

Unless the dealer is going to give you full credit for the extra cost of the 19s, I'd keep them.
so which has a better cornering grip 19 or 18s I can't translate it from your answer
 

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SLT09_ACADIA said:
so which has a better cornering grip 19 or 18s I can't translate it from your answer
And well you won't! A whole lot of it depends on tire construction, pressure, type of suspension, etc. Way too many variables!!

The concern should be speedometer/odometer accuracy and the DIC mpg calculations, etc.

Pay no attention to the man behind the curtain!! :banghead:
 

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speleos said:
And well you won't! A whole lot of it depends on tire construction, pressure, type of suspension, etc. Way too many variables!!

The concern should be speedometer/odometer accuracy and the DIC mpg calculations, etc.

Pay no attention to the man behind the curtain!! :banghead:
well why not we are talking about the Acadia and the factory tires 18 vs 19 they come with. Which corner better on cornering all at the same speed same tire pressure etc..... :banghead:
 

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If all else is equal including overall diameter the 19" will corner better, less sidewall means less flex.<< which is why larger rims (+2,+3 size) ride different (some say rougher). Although this is only valid for pavement/hard surface. Once you get onto gravel/dirt the more sidewall the better, within reason.
 

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SLT09_ACADIA said:
well why not we are talking about the Acadia and the factory tires 18 vs 19 they come with. Which corner better on cornering all at the same speed same tire pressure etc..... :banghead:
You can get the dealer to put whatever tire you want on the stock Acadia rims if the size is available. All you have to do is ask and step up to the counter ($). And what happens if you buy some off the wall-sized wheels and have the dealer mount them for you prior to delivery?
 
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