It also depends on how rounded the tire profile is. Performance tires may have more rounded shoulders for cornering while economy tires are not. Since the strut plate is on an angle you can't always tell by reading the numbers.

 

thanks for are the feedback. I'm headed to the tire store and try some sizes.

 

Here is an update, 245x45x18 fit also.........plug that into the tire calculator.

 

Wow. That's amazing they clear because I spec'd it at 26.68". I guess it's either the sloped edge of those tires or rim offset. Or both.


(Even more amazing is it only took the OP 9 months to come back and say "thanks for the info".
To be fair, at least he did come back with the thanks. It is appreciated. )

 

I went with a change from the stock 215/55R16 to 205/60R16 on two HHR LS's. Slightly larger diameter but narrower section ensured no clearance issue. That particular size was on closeout and really cheap in a Pirelli P4, quiet, smooth, and the narrower profile is better in the snow. They've been pretty good. Speedo went from slightly fast to perfect. Overall very happy.

Dealer gave resistance to the change, I pushed back, they claim to have checked with GM and got an official OK.

If you do this, not reduce tire pressure and maybe even increase it; this size has a smaller contact patch.

Having said all that, had the price been the same I would have stuck with the stock size. TIRE BRAND/MODEL IS MUCH MORE IMPORTANT FOR RIDE COMFORT THAN A SMALL CHANGE IN SIZE.

I'll never again buy less than an H speed rating for any car, preferably V, W minimum for a fast car. Had too much trouble with balance, roundness, and failures with lessers.

On another car, not HHR, I got Pirelli Cinturato P7 All-season +II, V-rated, very comfortable and quiet. Great value, very happy. Tire Rack has it IN HHR size, it seems.

Good luck.

 

18x9.5+22 varrstoen Es2’s and 245/40/18 falken rt615k+. Probably going 275 in the front next time.

Just bought these for the fronts, going to use them with a 24.5 x 8.5 x 15 slick