Originally Posted by Tourist in MSN

In USA there are post office envelopes that are made of Tyvek. I have no clue if they are used in Canada or not. I cut pieces of that Tyvek to carry with my spare tubes in case I need a tire boot. Never needed one yet, but I keep my spare tubes in zip lock bags and a piece of Tyvek is in most of those zip locks.

If you put some Shoe Goo or Seam Grip on your inside tire to protect the cord, you might want to have a piece of Tyvek or some other tire boot material against the stuff you add to the tire to make sure that the inner tube does not stick to the stuff you added to the tire. Or, maybe some talc powder would serve that purpose.

Some tours I carry a spare tire, some I do not. When I carry a spare, it is not a replacement tire to replace one of the tires I am rolling on, instead my spare is the lightest and most compact tire in a useable size that would fit on the bike to get me to the nearest bike shop. Example, my trip last summer in Canadian Maritimes, I had read that it is almost impossible to buy a bike tire on Cape Breton Island so I carried a spare. I used 57mm wide tires on the bike and I think my tires were rated at 650 grams (before I wore off some of the tread), but my spare was rated at 47mm wide and it was 430 grams on my scale. And my spare is in a zip lock baggie too.

When I was in college, I drove a long distance for a summer school program in another state that I needed to attend for my major, drove that in my old 65 Ford F250 pickup truck, it had inner tubes. Got a flat tire in the middle of the night. The garage that fixed my flat told me that there was a little bit of something like a sand grain that had worn a hole into the inner tube that caused my flat. Ever since then I have been careful to keep my spare bike tubes and tires in plastic bags to keep them clean to make sure that I did not accidentally add a sand grain to a tire if I had to change a tube while out on the road or trail.