Rims -- 19 x 8.5
+40mm offset
Backspacing: 6.37
Tires -- 245/245/19

On my stock wheels and tires, it looks I only have about 1/2 of an inch of clearance from the tread of the tire to part of the strut in the front and maybe 1/4 of an inch of clearance in the rear w/ the same part of the strut. Below is the stock 235/50/18 and 245/245/19 tire size comparison:

235/50/18:
sidewall - 4.6 in
radius - 13.6 in
diameter - 27.3 in

245/45/19
sidewall - 4.3 in
radius - 13.8 in
diameter - 27.7 in

As you can see, the 245/245/19 tires would end up being about 1/5 inch taller from center of the wheel to top of the tread. Do you guys think the 19 inch wheels with the 245/45/19 tires would fit my 06 Monte SS?

 

245/40/19 would be a better option. With a 45 series tire you may hit the spring pearch on the strut.

 

I found, and have since misplaced, the link to a good calculator that shows exactly what effect the new offset has on everything as well. Remember, you're pushing the wheel out 12mm with the new +40 wheel, compared to the +52 of the OE wheels. BUT, you're widening the wheel & tire overall...

I'll see if it's posted somewhere at NAIOA...it took all of your measurements and gave you a final width and distance from the inside of the car.

However, if the OE TIRE is 235mm across the section that touches the road, it matters not the width of the wheel, right? A 245 tire on a 7.5" wheel is still 245mm on an 8.5" wheel...the ground coverage does not change, so the upper width shouldn't either...right?

That said, the measurements that should come in to play here is the 12mm outward that your new setup is, minus 1/2 of the section width distance of the two tires ((245-235)/2 = 5mm). Your new tire is now 7mm further out from the perch, which is roughly 1/4".

Lastly, the height of the new tire is closer to 1/2" taller, than it is 1/4" (27.68 - 27.25 = .43")...so that's going to affect where on the perch you need to measure from.

Ultimately, if what I have ^^^ is right, you need to compare the distance from your tire and spring perch from 7mm in from the edge of your current tire. If you have close to 3/4", you might be OK. If not, go with a different tire as smug mentioned. That tire is just over 1/2" smaller/shorter, and will result in your speedo being off (slower) by 1.2mph @ 60, so it's not too bad.

Here's a list of tires available in the second of the two measurements...about 1/2 the number of the 245/45's:

Bridgestone Blizzak LM-60
Bridgestone Dueler H/L Alenza
Bridgestone Turanza Serenity
Dunlop SP Sport MAXX
Falken FK-452
Goodyear Eagle F1 All-Season
Hankook Ventus S1 EVO K107
Hankook Ventus V12 Evo (K110)
Kumho Ecsta SPT (KU31)
Michelin Pilot Primacy
Michelin Pilot Sport A/S Plus
Michelin X-Ice Xi2
Pirelli P-Zero Nero All Season
Pirelli P-Zero Run Flat
Pirelli Winter 240 Sottozero
Pirelli Winter 240 Sottozero Serie II
Pirelli Winter 240 Sottozero Serie II - R.F.
Yokohama ADVAN S4
Yokohama ADVAN Sport

 

Buff...Here is a wheel calc that I found online.

http://www.wheelsmaster.com/rt_specs.jsp

It stated that I may have some issues with the 245/45/19 under the fender. I'm thinking I may have to go with some 18inch wheels w/ the good ol 235/50/18 tires

 

I don't believe that you'll have any issues with the 245/45's, but you might if/when you drop it. I can't compare what the stock wheel/tire combo looks like on the stock suspension anymore.

If you lower it, you may not hit the quarter panel lip, but you very well could hit the fender liner, like I do. You could always plan on rolling the rear lip...might cost you $100-150 at local body shops.

EDIT: yeah, that's the tire calc I had bookmarked at home...nice stuff.

 

You can always take a baseball bat and do it your self...

That's how we do it on the west side which is the best side....

 

I did that as well...but have the battle scars to prove it. The paint on both sides is chipped pretty badly...I gotta get some touch-up paint and deal with that accordingly.

And I agree, "Wes'side is the bes'side." ...as long as we're not talking about the country as a whole