Is it possible to have the speedometer recalibrated for my new 17"s that I am going to put on? I know it's not a big deal, but my speedo is off my 1mph already, and putting the larger wheels on will throw it off a little more. I know my dad did this on his Silverado when he changed the rear end and wheels, but I didn't know if this is possible (or economically feasible) to do in the HHR...

 

Because of different differential ratios, I think the dealer can reflash the computer for that option. Check with Chevymgr, he'll know.
On a side note, you can change your tire size within an inch and it wont really matter. Here's is why, the tire from the time they are new until they are worn out will change the OD almost one inch from the tread wearing off. Nobody says that it needs to be recalibrated because of tire wear. One more thing, you can't go to big on the front or it the tire will rub bottom of the spring perch.

 

Just because you're getting bigger wheels, doesn't mean you need bigger tires. Get some with a lower profile that are close to the od of the stock tires...

 

What he ^ said. you can match the factory OD by going with a lower profile and nothing changes on the speedo.

 

I know I've asked tire questions before, but it's just so dang confusing. I really wouldn't care, but the fact that it's off 1mph now, then if I throw another 1 or 2 that makes it 3 off. That's getting a little bit more than I'd like...

All I'm going from is the factory 16"s to the factory 17"s...nothing more than what would have come stock, but just not on my particular HHR.

Wouldn't lower profile tires cost more though?

 

One thing I dont like though is with a smaller tire, the ride will be rougher. Don't know how many of you have ever driven in Michigan, but that's pretty important. Also, the Flint area has about the worst roads in the state, so it's a double whammy...

 

Just stay with the same over diameter and nothing changes. Period. Even the ride won't change unless you choose to go to a poor riding tire. Most of your ride comes from your suspension.

 

Obviously you've never been to Michigan... Ride does not depend on suspension, you are at the sole mercy of the potholes!

 

potholes don't count toward ride on anything other than a hoovercraft.

 

Oh, my.....


FYI, potholes in Michigan can range in size from a few inces across to a few feet, with the depth limited only by the amount of resurfacing done.

Shortly after buying my HHR, I hit a pothole in the dark at 25 MPH that flattened 8" of rim circumference, and caused the tire to lose 20lbs of air instantly. I had road hazard protection (cost me $200 when I bought the car) so I went to the dealer the next day. They replaced the rim, tire, and TPMS sensor and re-aligned the front end. The tire and rim were covered, so all I had to pay was the alignment and TPMS sensor cost.

8 months later, another pothole claimed another wheel, peeling the rim edge back 180 degrees.

Fortunately, the TPMS survived, but I needed another alignment. I went back and measured the pothole, it was only 10 inches across, but was an astounding 8 inches deep! It literally swallowed the wheel when it hit.

Michigan potholes are serious business, I know of cars that were totaled because of severe suspension damage.