lesser evil: 18" tube in 17" tire or 17" tube in 18" tire?

[ratguzzi]

Getting my 04 Ti ready for work travel and I am stuck with steel spoked wheels on it. I would like to bring just one tube with in case of an emergency. Of course, I will have a tube patch kit but in case it didn't work............... .....
I am leaning toward the 17". I have had more rear flats than fronts. And if I had to change it on the road, I wouldn't have to redo it once I got to a bike shop. Front would be easier to swap out later.
JB

[fotoguzzi]

my flats always were the rear tire.

[Daniel Kalal]

I've done "too small in a larger tire" and it didn't end well.  My vote would therefore be "too large in a smaller tire."

[RayB]

I'd go with the 17. The larger tube will be creased if used in tear...more heat from flex, etc

[ITSec]

I tend towards the 'replace at rear, patch at front' concept, though I haven't had to deal with this for a long time. My DRZ had same sized wheels for Super-Motard configuration, and the dirt wheels were so different there would have been no way to use the same tube even in an emergency. It was more a matter of the effort involved if a patched rear needed further attention.

[Kiwi_Roy]

Convert to tubeless with the application of silicone sealant over the nipples.

[ITSec]

Convert to tubeless with the application of silicone sealant over the nipples.

Wouldn't that also raise the question of the rim's bead seating area and its ability to hold a seal?

[Kiwi_Roy]

Wouldn't that also raise the question of the rim's bead seating area and its ability to hold a seal?

Well I guess it would but it works for my 72 Eldorado, a 46 Indian a friend owns and all his Jap bikes.
It could also be argued that the cast wheels on my California II are not tubeless either just don't tell it.

The only problem I have had is due to cheap silicone that won't bond well to the aluminum rims.

[FGO]

You can buy the correct tube for the cost of two bottles of your hotsauce :)

[ratguzzi]

Decided to add saddle bags over the gas tank like I used to do on my raT-3. I can easily carry both tubes now.
JB

[Wayne Orwig]

Decided to add saddle bags over the gas tank like I used to do on my raT-3. I can easily carry both tubes now.
JB

Even better.

I would never take a smaller tube and stretch it over a larger rim. I have had them fail from being stretched.
I'm sure that a large tube on a small rim might wrinkle, and that may not be great, but I'll bet it would get you home.

[Idontwantapickle]

Stelvio.
Problem solved.

[ratguzzi]

Stelvio.
Problem solved.

$10k later and can't do much more than a rough dirt road!!
JB

[rocker59]

Wouldn't that also raise the question of the rim's bead seating area and its ability to hold a seal?

Not on modern DOT MC wheels. 

[rocker59]

You can buy the correct tube for the cost of two bottles of your hotsauce :)

Yeah, but if you're packing light, two tubes does take up space...

Though, I used to carry two tubes, when travelling on the Quota.