Okay sort of new at this... did some research, reviewing what I learned so far; so correct me if I am wrong.

------ 2009 HHR LS (STOCK, OEM)------

tire: P215/55 R 16 wheel/rim: 16x6.5J inflate: 30 psi (all four tires)

------tires------
P (passenger automobiles)

215 (width in millimeters, [215 mm = which equals 8.46 inches]; looking at the tire from the front and measuring the width of the surface that contacts the road)

55 (spit-balling this one: a ratio/percentage that expresses the height of the tire side wall. This measurement compares the tire width [215 mm, as stated above] and the size of the tire wall as seen from the side of the tire.
The tire wall is measured from inner edge of the rubber wall to the top of the tire wall.) (So, 55% of 215 = 118.25 mm [which equals 4.65 inches] ) I know what you are thinking... why not just say 118.25 mm... I got no clue.

R (radial construction)

16 (expressed in inches; and the overall diameter of the rim that is designed to fit that specific tire; see below)

------rims------
16 (expressed in inches; the diameter measured while looking at the rim from the side and measuring from outer edge of the rim - across the center, to opposite outer rim edge.)

6.5 (measurement that expresses the width of the rim in inches [which equals 406.4 mm]. Looking at the rim from the front, measuring begins from the inside wall if the rim - where the tire makes contact with the rim - to the opposite inside wall of the rim)

5x110 (five bolt pattern expressed in millimeters; (which equals 5 x 4.33 inches), measured from the outer edge of one bolt hole to the center of the second next bolt hole; that means skip one bolt hole and measure to the centr of the second bolt hole)
Again, I know what you are thinking... wtf. It turns out, other bolt patterns have an even number of bolts (4, 6, 8) and they are measured from one bolt hole center to the opposite bolt hole center. But, 5 bolt patterns do not have a bolts directly opposite each other, and for some reason the are not measured from center to center; the first bolt hole measurement starts from the outside edge of the bolt hole to the center of the second next bolt hole. see bolt patterns page for images.

? (rim offset is a measurement that is taken while looking at the front of the rim. Measure from the middle of the rim width [half of the 6.5 inches as stated above] of the inner edge of the bolt hole surface. See the see bolt patterns page for images.

SUMMARY-----

So the overall volume of a stock 2009 HHR Rim and Tire is:

WIDTH = 215 mm tire width or 8.46 inch tire width

HEIGHT = 473 mm diameter or 25.31 inch diameter
(118.25 mm tire wall times 2 (the upper and lower tire walls) equals 236.5 mm --- plus --- a 406.4 mm rim; 236.5 mm + 406.5 mm = 473 mm height)
(4.65 inch tire wall, times 2 (the upper and lower tire walls) equals 9.31 inches --- plus --- a 16 inch rim; 9.31" + 16" = 25.31")

Its dark outside now, other wise I would go out and measure my findings.

REASON-----
I live in the mountains and I would like to raise the undercarriage, already broke the manifold and muffler coupler, and I am thinking of 15 inch wheels instead of the 16 inch wheels.
The 15 inch wheel covers (full moons) are half the price.

 

You are limited tire height wise by the spring mount on the strut.

 

What am I missing? I am not sure what the reason is for that OP's post. There are all sorts of details, numbers (some correct and some incorrect, and some irrelevant) that don't really seem to indicate what info or advice he is looking for until the very end stating about "raising the undercarriage" ... but I gather he means the opposite - to increase the ground clearance. If he uses the search tool he will find the maximum height of tire that can be fitted with the limited clearance of the spring mount on the front struts.

 

Well you solved the problem yourself.
Get 15 inch wheels with the covers and it will lift your car about 2 feet.

 

I don't know how low clearance would be responsible for a cracked manifold.
The flex tube is a hugely common failure point (mostly from bad motor mounts).

 

Thank you... "increase the ground clearance".
My thinking was buy 15" rims and buy tires that would would add another inch of clearance.

By doing the research in regards to the stock rim and tires of an HHR, I figured I would learn something. This was my way of thinking out loud; this forum is so responsive.

Thanks,
Greg

 

Unless you can figure a way to make the part of the tire below the axle higher than the part above it you are stuck with about 25.5 inches (I don't recall the exact).

If you don't care about your teeth getting rattled out of your head you could put spring spacers on th the springs to raise it.

 

It can be done..........if you want to spend LOTS of money.