I looked at specs on the GM website, some models have an 18" compact spare instead of a 16". I wish they would do what you suggest, I suspect it would hang down too low, they are pretty low as it is.

 

Would seem to just be an issue of forking over the $$$. The spare tire location has to be able to handle the flat tire when you put the spare on the ground. The outside diameter of all versions of rim/tires is pretty close.

Actually, the spare tire is same tire it appears as the 4 tires on the ground on the Base and WT versions of Colorado.

I don't remember anything in the owner's manual about storing the flat tire in the bed on the Twins. On the Ridgeline, a FS tire will not fit in the spare tire compartment, so they have explicit instructions on how to secure a flat tire in the bed of the truck.

 

I don't care what the rim size of the spare is, as long as the tire diameter is correct.

 

the only time i think its nice to have a matching rim and tire it to rotate in a 5th tire, but lets face it an alloy wheel under there will be ruined in no time, and a wider tire will be the first thing to drag on the ground

makes more sense on a jeep with a tire carrier on the back, but long as the OD is close to the tires you have on then itll get you out of a pinch, if its a few sizes smaller (if you put on 32-33") you might want to make sure its on the front and dont use 4x4

thinking im going to move mine into the bed anyways instead of dragging my spare through the cut corn and wheat, once the air dam is gone the spare it the lowest hanging thing back there

 

Bingo... I was floored that the tire was a wimpy temp. If one is out in the boonies on a shale road that gave one a flat... that spare is not much help. I immediately found a stock aluminum rim on eBay and then bought the same tire I use for a spare . I am running 245 75 17 E rated tires as I do a lot of load carrying on bad dirt/shale "roads". I feel better. It fit on the spare tire cable. Anyone want a rim and temp tire for $75 + shipping? I have it posted on Craig's List too.

 

We all refer to it as a "spare tire" when, in reality. it is not. It is a temporary replacement only and not meant for regular duty. It's purpose is to get you to the closest place for repair/replacement of the flat. It is not intended for driving as if nothing had happened.

About the only thing with a real spare anymore is a Wrangler. At least my truck has a temporary replacement that is good for more than 50 miles and 50 MPH.:nerd:

I haven't checked on the tires for our trucks, but in many cases lately, I find no one stocks many varieties of tires, they order them from a warehouse and it is 2-3 days delivery. One tire place tried to talk me into changing sizes on my Wrangler to a tire size standard on Silverados because he stocked those.

I figure if you have OEM tires on a F150, Silverado/Sierra, Accord or Camry, you might be okay.

 

I looked underneath my truck when the lift was being installed, and my spare is the same size as what's on the truck. Not the same rim obviously, but everything is the same size.
Having said that, because it sits close to the exhaust, and therefore there's a heat shield mounted in-between, it limits the tire size to basically what comes stock. Maybe you can go up one size, which is useless when you've lifted your truck and are running 33's

 

@yokev If your spare is the same as what came on the truck, you must have a WT or base model. The spare is a 16" rim and 17's are stock on the higher models.

 

What Yokev means is that the OD of the tire is the same as the rest of them.

Many people misunderstand the term "full size spare" as meaning identical size spare. It is not. In the case of the twins, that 16" has the same OD so that it doesn't effect the 4wd system. If you look, it also has the same weight rating as the factory road tires. That is what the car companies mean when they say full size spare... not identical size, but same OD and weight rating and can be used for continuous service, unlike a temporary that is rated for 100 miles or something.

I am planning to change my spare to a 215/85R16 when I get my winter tires. That is as small as you can go on the 16" rim and keep a close enough OD to the factory tires. It will drop a few pounds, but more importantly it won't hang down so far. There are plenty of tires in that size that have the same weight rating as the factory 17s or 18s. You can even get load range E in that size. The point is that I will still be able to install it and use 4wd, or keep towing till I get somewhere to deal with the bad tire. I won't be doing any knarly off-roading with the Colorado.

For many years and several vehicles, including my Astro AWD, I got an extra aluminum rim and put one of my tires on it from when I bought new ones. On the Astro it was important since that had a full diameter 'temporary' that would not handle the weight if I was towing. I also always carried a plug set and tools and a small compressor. On the other vehicles I was just being "prepared." I have since decided that with the new truck, I have roadside assistance, so the spare only needs to let me get back close enough to civilization to make that call. I also got too lazy to do 5 wheel rotations years ago, after I figured out that you didn't increase tire life enough to break even on the fifth tire most of the time.

If you off-road in shale and rocks, you are crazy if you don't have at least one, if not two, tires in the back of the truck while you are out playing. You also are likely running something with a good sidewall.