Yes, from 225/45 19 to 245/45 19, the diameter gets bigger.
But if you put 245/45 19s on a 7.5" width wheel, vs. a 8.5" width wheel, what then? It is my understanding that wheel width can affect diameter because of how the wheel affects the tire.
Take a donut and put it between your hands. Now squish the donut. The diameter gets bigger.
The difference in diameter between 225/45 19 and 245/45 19 is already close to 3%. A 7.5" wide wheel is on the narrow side for 245/45 tire, and I suspect that the squish to get it to fit will increase the diameter a bit over what it would be on a 8.5" wheel. I don't know if this is actually significant, but I figure I'd point it out if that's a factor for him.
Because I am interested in a 8.5" wide wheel, I think sticking with 225/45s is more stretch than I want. 235/45 19s would be ideal, but its a size with very few tire options. I don't want to do 245/40 19s because they are shorter than stock and I want the extra sidewall here in NY. The 245/45s also fill in more of the wheel arch, which I think is better visually. Also, there are lots of tires in that size, and it makes shopping for tires much easier/cheaper.
Sorry if I wasn't clear before.
EDIT: So I looked it up, and it seems that this is not really true on steel belted radials.
Thanks for providing the pics and glad it quelled the noise and harshness. Any difference "felt" with handling and no issues experienced by the garage when mounting on our stock 19"ers? My new #1 choice if so and think it looks great sitting on there as well!
Yes I am on stock wheels. I can confirm, no size or rubbing issue. Michelin PS AS3 is a fantastic tyre, enjoy!Hertz007 - just to confirm that your 245/45/19' are on the stock wheels (they look like it from the pics, but I am not sure as mine is a 2018) with No size/rubbing Issues?
Anyone else out there with a 2018 put 245/45/19's on a Signature?
I just ordered Michelin Pilot Sport AS 3
AFAIK the compatibility depends on the brand AND tyre type AND sizing. I'd recommend using the compatibility tool on the discount tyre website. Then if you have issues later it's on them. My guess is that that discount tyre just input the compatibility list into their tool which Michelin or Continental provide. Don't think they would provide 50k miles warranty on a hunch! BTW I have attached a screenshot of the various options for the DWS06 in my photos (see previous post).I found a great deal on tires 245/45/19....will they fit on stock wheel?