2009-2015 Cadillac CTS-V General Discussion Discussion, my spare tire solution, sort of in Cadillac CTS-V Series Forum - 2009-2015; So, they say the thrill is in the chase ... so , I was not content with the very expensive ...
So, they say the thrill is in the chase ... so , I was not content with the very expensive spare tire kits that are out there, and I can not find an appropriate spare tire from a junked car, because it seems all the local junkyards not have very late model cars.
So, I did a lot of measuring, and then ordered a dr37 wheel in 18x8 (5x120 bolt pattern), and the cheapest 215/45/18 tire they had - a total of $240 mounted, balanced and shipped to me. This combo gives a tire diameter of 25.6", which is just the tiniest bit taller than the spare tire kits others have gotten. The stock tire diameter is just about 27".
As you can see in this picture of the spare next to the stock front tire on the car, there is almost an inch difference in height.
If I was to use this spare, I would only put it on the front. not sure how the limited slip works in the rear diff, but i would prefer not to find out.
this wheel does bolt right on to the stock hub, no spacer required, but I think will need narrower lug nuts.
It also fits in the rear spare tub, but not as well as my measurements said it would. if i deflate it, then it mostly fits. it sits up a bit. I can not put the tire cover back in place, but I can fold the folding floor of the wagon back down. I plan to put it upside down in the well, and put the inflater in the wheel, along with a wrench and the appropriate lug nuts. Also need to get a jack, but scissor jacks are a dime a dozen anywhere. If the tire is not deflated, it sits up a little higher, but the floor still goes down.
Overall, I think this will work as well as the spare donut tire that is out there, and no spacer needed, so that much less aggravation when actually changing the tire in my suit on the way to work. But I have to get lug nuts (which will come for free when I buy winter wheels) and a jack. In the end, i have saved a couple bucks, although for $350 you can get the whole package from performancespare.com, and that guy did seem very nice.
If i remove the plastic spare tire interior panel, I bet the tire would fall all the way in, but I dont mind it sitting up a bit for now. still figuring it out. i also have to find a spot to mount my sub amp down there (another post in a few days)
It should mount on the rears, you just don't want to drive on it, correct? IMHO, since it's an emergency measure (to get to a tire shop, or home), you could obviously drive appropriately as you would with any other spare on the rear - or is there some other reason you're thinking it wouldn't work on the rears?
i am sure it will fit fine on the rear, but the diameter is different, and with a mechanical locking rear diff, it might wear the differential. i am not sure how this diff works - if it is locking at all...
i bet a 215/40/18 would fit all the way down, since it only needs a millimeter or two. but tire rack does not have any cheap wheels that we are sure will fit. the deal is buying the inexpensive dr37 plus $87 tire from discount tire, who mounts and ships for free. And given that the tire is already smaller diameter than the stock, I would prefer to keep as much height as possible.