My 15" Sonic Steel Wheel + 205/65-15 ~$145 spare tire solution - test fit with pics

My 15" Sonic Steel Wheel + 205/65-15 ~$145 spare tire solution - test fit with pics

So I know there are a few threads already talking about spare different spare tire solutions for the Bolt for those of us who don't feel comfortable relying on the self sealing OEM tires and roadside assistance. In reading various threads about spare tire ideas like getting a Cruze spare and mounting a different temporary spare tire on it or buying an entire extra OEM wheel and tire I came up with this idea after reading what people were running for winter tires. Seems like this is a great balance between the cost effectiveness of the junkyard spare cruze wheel and a new tire and the practicality of a full sized tire & wheel.

I had already planned on getting a spare tire for the car, I've had my last car (still have it) since I bought it new in 2004 and in that time I only needed to use the spare tire once but when I needed it it really saved me a lot of time and headache.

As it turns out not 2 weeks after I bought the car I pulled into a driveway off-center and my right front wheel went over about a 2" of the transition where the driveway curves up to reach the curb, wasn't even a particularly jarring bump but it was enough to chunk my sidewall and destroy my tire, was completely flat within 60 seconds. What was worse was because I was miles from home with no spare and no jack I did not have a lot of options. I did not want to call GM roadside assistance which would just tow me to the Chevy dealer where they would sell me an overpriced crappy OEM tire (assuming they even have one) so I spent the next 4 hours running around my city (walked a mile to borrow a car, drive home to get a floor jack, drive back to the car to the pull wheel off car, drive wheel to tire store to have a used tire temporarily mounted, drive back to put wheel back on car, etc.).

Picture of tire with sidewall damage (you can see a small nick in the wheel).


Now I've got 4 new tires (I was planning on replacing these anyways at about 1000 miles but the incident accelerated my plans) and a renewed urgency to come up with a spare tire solution.

As I mentioned above I had been doing some research on what other people had done for a spare tire. I was planning on picking up a Cruze spare on eBay and then changing the tire for that to one that's a closer match to the OEM tire size (the Cruze spare is quite a bit too small) but that seemed wasteful and there are limitations with "temporary" spare tires anyways, you're not supposed to drive on them faster than 50-55 MPH or drive on them for longer than ~50 miles. Add to that that even the "closer" temporary spare you're going to mount on the Cruze wheel is not a great match for the OEM size so you could never use one on the front wheels without risking damage to your differential. I know a couple people have bought a new OEM wheel and mounted a full sized regular tire on it but that's a very expensive solution for something you (hopefully) never need to use.

I was checking out the winter tire thread and saw that some people were using 15" wheels intended for a Chevy Sonic and 205/65-15 winter tires. I figured that if you can run 4 of those in winter why not run 1 of them as a spare? One key advantage of this is that the 205/65-15 is an EXACT match spec wise (there is always going to be some difference in tire dimensions from tire to tire even in the same size) so I could in theory run this size on a front wheel at least for a while.

Went to Tire Rack and told them I had a 2014 Sonic Hatchback. Found the 15x6 steel wheel and a decent but inexpensive non-directional tire (since this tire could need to run in either direction) and ordered it. The wheel was $53 and the tire was $56, buy a tire and wheel from Tire Rack and they will mount and balance for free. I did have to pay $34 for shipping so the total came out to $143.94 which I figure is about $30-$40 more than I would have paid for a Cruze spare wheel and new tire for it.

This weekend I test fit the tire, took measurements and found that everything seems to fit great.

Here is the new wheel next to my OEM wheel. At first glance the new one seems quite a bit smaller.


Here it is between my OEM wheel with new tire and one of the 3 (unmounted) factory tires (I have these for sale BTW). Looks like the factory tire is the smallest.

Unmounted Factory tire (Left), New Spare (Center), Kumho tire mounted on OEM wheel (right)


I put the factory tire in the middle and stuck a board on top for vistualization purposes. The factory tire looks much smaller here but it's really not a great comparison since the factory tire isn't even mounted on a wheel.


Put the new spare and the OEM wheel next to each other and stuck a level on them. Looks like the tires are actualluy extremely close to each other after all.




Extreme close up of bubble.


Now I understand the concept of wheel offset but I don't know how to tell what that means when you are comparing wheels with two different widths. I figured one fool proof way to figure out if I was likely to have clearance problems would be to measure the depth from the tire to the rim.


Looks like the new spare does not portrude into the wheel well as far as the OEM wheel. Pretty much what I expected.



Now Tire Rack included new lug nuts with the new tire, I put them next to the factory lug nuts for comparison. Looks like the seat of the two is the same, the tire rack nuts are open instead of the closed factory nuts.



When I mounted the spare on the car I put one of the factory nuts on hand tight to see if these might work. Seems like they would though I did not attempt to torque it down.


Here's the wheel mounted on the car, I test fit on the front wheel because that's the one where I'm more likely to have clearance problems, either from the wheel not clearing the brake caliper or from the tire rubbing on something when I turn (though the measurements I already took told me that wasn't going to be a problem)


While I still had the car up on the jack I spun the wheen a few times by hand to make sure the brake caliper wasn't a problem. I also turned the steering wheel to full left and full right lock to make extra sure that nothing rubbed. Of course that would even be less likely with the car on a jack with the suspension not compressed.

Once I had the car down on the wheel I also repeated turning the steering wheel to full left and full right lock and drover forward and backwards a bit. No clearance issues at all. Now of course it's theoretically possible that when going over a bump you could have some rubbing but the measurements I took tell me that's not going to be a problem.


Once I got the new spare wheel back off it was time to put it in the back where it's going to live. It actually took up more space than I was expecting it to. At least with the factory all weather cargo mat installed it comes up right to the false floor. There is room in the wheel for my L1 charger though.


Putting the false floor back in place it's a very tight fit, in fact you have to put the false floor in at a shallow angle to get it into the slot. The false floor is in physical contact with the spare. This means there's not enough clearance to put the cover I already bought on the spare tire but I'm OK with it in general because it means the tire will help support the weight of anything heavy I put on the false floor. That floor seems way too weak for a lot of the things I carry but the tire will support it more than adequately I no longer feel I need to replace the false floor with a piece of 3/4" plywood as I was planning.



I weighed the new spare and the OEM wheel and I wrote down the measurements but I can't find where I wrote it down. As I recall the new spare was about 10# lighter than my OEM wheel and Kumho Ecsta PS31 tire. I'm thinking this might make this wheel and tire size a viable option for hypermilers because between the lighter weight and being a slightly narrower tire it should be a decent amount more efficient. Tire Rack does list several LRR tires in this size and most of them are under $100/tire.


That's the meat of it. I feel really good about this solution, being as the spare tire doesn't have the exact same diameter as the OEM wheels I probably would not use this tire on the front wheels if I had a choice but I like that I could drive around with this on the rear wheel indefinitely if I needed to and it would be perfectly safe.

If anyone wants to see the full resolution & uncropped pics I created an album in Google Photos. Here is the link: Bolt Spare Tire