I have a 2012 g37 sedan with big akebono brakes , tires are 245/40/19. Since going with akebono, I was looking for a spare tire that would clear those big brakes. Based on my research on the forum here , it seemed like the 19inch spare from.the coupe would be the only option. However there is someone on Facebook market place selling an 18inch spare made for the infiniti red sport with akebono brakes. But I have 19nch rims and these are 18. Im left with wondering if that difference in rim size matters. Please help me
the spare dimensions are 145/70/18

 

Best bet is to have the spare the same diameter as the mounted wheels.

​​​​​in your case, the spare should be a 19. Otherwise the car would not sit correctly and potentially have controllability issues. Not saying it would be unusable in a pinch. But given the choice, I would go with the 19.

All bets are off if your G is AWD (G37X) in which case it absolutely has to be the same size or there is risk of damaging the transfer case internals.

 

my g is awd , your answer is very helpful. Thank you so much 💓

 

I asked a similar question at the dealer years ago when I took delivery of the car. As I have the Coupe w/ the sport 19's, I noticed the spare was 18" and wanted to make sure there wasn't a mixup. I was told that Nissan does not have a 19" spare tire. They are either 17" or 18". The diameter of the tire is what makes up the minimal difference and keeps everything happy.

The same applies to the 370Z and the Q's- even the Red Sports though most of them came with the "tire repair kit" instead of a spare (gotta pinch those pennies)...

 

This is what the seller told.me also. He said infinit doesn't make 19 spare. So I guess I can go ahead with the purchase
I appreciate all the answers 🙏

 

There are two types of spare for the Z/G and both are extremely similar. The one you need is a 18 inch OEM spare. It doesnt matter which vehicle it came out of, they're all the same since they need to clear the same caliper.

 

To the OP, keep in mind, your sedan originally came with 18" wheels (assuming it's a g37s). So no issues with the 18" spare fitting. Also, some aftermarket 18" wheels will fit the bbk too. My winter tires had barely 1/4" clearance between the spokes and calipers, but they did fit.

 

I stand corrected : ). Sorry for the bad info and thanks to everyone who got it right! I have to learn to never post before 10am....