# 16" spare tire with 18" tires



## dlmetzger63 (Sep 28, 2017)

I have the 2018 hatchback with 18" wheels. The spare is a 16" donut wheel. This seems very dubious. It's about 2" shorter than the 18" wheel. The manual says not to drive over 50 mph but I'm not sure 25 mph is a safe speed given the size difference between the wheels. Has anyone been forced to use the 16" donut with the 18" wheels?


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## Patman (May 7, 2011)

I had the same situ with my Eco that has 17 in wheels and wondered about this myself. The Eco does not have a spare and the only one I found was a 16 inch. I figured this could only work if it is first off *put on in the rear and it is only to get you to a place to have the regular tire/wheel fixed*. The idea of spare tires anymore is a thing of the past. It is not like the old days where you used to "rotate the spare into mix" I don't even remember my last flat tire FWIW.


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## Robby (Mar 1, 2013)

Most likely, because of a taller sidewall, you will find the outside diameter to be the same.....that is all that matters.

Rob


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## neile300c (Jul 8, 2014)

Robby said:


> Most likely, because of a taller sidewall, you will find the outside diameter to be the same.....that is all that matters.
> 
> Rob



This is correct. For instance, the 16" stock tires and wheels on the LT are the same diameter as the optional 17" wheels and tires and the same diameter as the 18" wheels and tires


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## dlmetzger63 (Sep 28, 2017)

The outside diameter of the 18" wheel is 2" larger than the 16" spare wheel. I'm aware of the differences between rims and tires and that an 18" wheel could have an outside diameter of a 16" wheel given different aspect ratios. This is not the case for my car. The spare wheel is smaller. This seems very dangerous and that's why I asked if anyone was forced to used the spare given my specific car/wheel/spare issue.


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## Robby (Mar 1, 2013)

Dangerous from the standpoint of less rubber meeting the road (width)......well, in a emergency maneuver response would reduced.
I suppose that is why they have a speed limitation decal......as well as a maximum recommended use mileage.

From the vehicle standpoint, the variation is within the ABS parameters so it will continue to function. If mounted on the front, since the differential is 'open', yes, the spider gears will be in constant movement, but again, the designers have taken this into consideration.

Like you, I've never been very comfortable when I had to use it, but I prefer that discomfort to no spare at all. Two of my cars are supplied with jacks, but no spares (Dodge SRT8 Magnum, 09 Mazda Miata).
Whenever I drive them I often try to visualize a plan should a flat occur. Although each has a compressor and sealant, I have no intention of using the sealant. Instead, I have a plug kit in each car in the hopes of being able to address a small puncture without too much drama.

My Cruze eco had the mini spare (standard with autobox cars) and 17 inch wheels. My current Trax's have the same configuration as you....18 rims with the mini spare on board.
As I said though.....regardless of sizing at least I can put something in the damaged tires place, believing the manufacturer got it right for short term usage.

May everyone's Christmas (and holiday) travels include not needing to play streetside tire changer.

Rob


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## Blasirl (Mar 31, 2015)

Just to reiterate what has been said so far -- The wheel diameter is about 26.1" no matter what the rim diameter is (16", 17" 18") on a stock Cruze.


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## dlmetzger63 (Sep 28, 2017)

My wheels are different. The 18" wheels on the HB are 24.625" in diameter. The spare wheel is 22" in diameter.


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## Blasirl (Mar 31, 2015)

My mistake, my numbers are for the Gen I. I must be getting seniler, more senile, well you know...


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