Tubes... options and flat prevention!

The bad news is, anything you do to prevent flat tires will add weight to your wheels. In general, you want to keep your bike light, and especially the wheels. But, on the other hand, you don't want to stop and fix a flat every mile. If you ride in an area where puncture-weeds and other hazards abound, you may want to take steps to avoid flats.

Puncture-proof tubes.
Puncture-proof tubes.
This was my personal favorite for avoiding snakebites (pinched tubes when you land a jump or corner hard with a low tire) back when I used tubes. And it's nearly impossible to puncture. This is the heavy, thick "puncture-resistant tube." The outer wall is thickest, but even the inner wall has extra rubber, preventing cuts from exposed spoke-holes when the rim liner shifts.

Puncture-resistant tires will add a pound of weight to your bike.

A puncture-proof tube is very thick. Which means it weighs a lot, making your hill-climb a bit more work. And the response of your tire to small rough edges will change. You need to decide whether it's worth it.
A tire liner can thwart those goathead thorns.
A tire liner can thwart those goathead thorns.
A tire liner can prevent simple punctures. It adds some weight, but not anywhere near the weight you'd add with a slime tube or a puncture-resistant tube. But the tire liner has an edge on the sides and (especially) on the end. After a hundred miles of bouncy, vibrating bike rides, it will probably wear a hole through the tube.

Tire liners don't prevent snakebites on turns or jumps, and they don't prevent cuts from exposed spoke-holes.

Tire liners are a good compromise for riders who don't ride violently, but are exposed to puncture-weeds.
You can buy slime in a bottle, or buy a tube that's already filled.
You can buy slime in a bottle, or buy a tube that's already filled.

Slime tubes contain a leak-stopping goo. I've used these with my kids' bikes. My opinion:  Slime tubes work fine for newbies and road bikers who encounter an occasional puncture-weed. Really hard-core mountain bikers will go for a tubeless setup with sealant.

The goo doesn't create a permanent "fix" for the leak. It tends to leak intermittently, unpredictably. And when you dunk the tube in the sink to find the leak -- guess what? -- you can't find it. For the same weight, you can use a puncture-resistant tube and never fix a kid's flat tire again. And slime doesn't give you any protection against cuts or snakebites.

Slime can stop a leak from a small puncture. But it doesn't prevent snakebites and cuts, and the leak won't be permanently fixed.

Some flats can't be fixed. It's a good idea to pack a spare tube!
Some flats can't be fixed. It's a good idea to pack a spare tube!
If you ride hard on rough rock, you'll get an occasional snakebite. (Snakebites are where the tube is cut top and bottom.) Sometimes these cuts are too big (or too many) to repair with patches. A spare tube, kept in an underseat pack, insures that you won't be walking. Make sure it's the right size, and has the right type of valve.
Press-on patches can be useful for tiny punctures.
Press-on patches can be useful for tiny punctures.
I usually carry a few press-on patches. (We give them to other bikers, because we prefer the strength of a glued patch. See below.) This gives a quick repair for tiny punctures. The bond isn't strong enough to fix the typical snakebite or spoke-hole cut. And with passage of time and rough riding, the patch may wrinkle and loosen, allowing the leak to recur.
The traditional glue-on patch is much stronger, especially for riding in rough warm conditions. It can cover larger holes.
The traditional glue-on patch is much stronger, especially for riding in rough warm conditions. It can cover larger holes.
For permanent, strong tire repair, nothing beats the old glue-on patch. Small patches fix punctures, while longer patches can seal cuts such as snakebites. Because a tube of glue tends to coagulate with age (once they've been opened), I buy a handfull of tiny tubes, rather than a big tube. I usually pack four 1-inch patches and two 1x2 patches (plus a spare tube) on every ride. You'd be surprised how often I use up everything I have -- but so far, I've never had to hike out.
Regardless of what tire patch system you choose, buffing the tire is the most important step for a strong patch.
Regardless of what tire patch system you choose, buffing the tire is the most important step for a strong patch.
Whether you use a quick-patch or a glue-on, you MUST buff the tube before the repair. Most repair guides recommend sandpaper. This gives a stronger, smoother repair than the metal scrapers.
In your underseat bag, you'll want a spare tube, patch kit, and complete tool set. My personal favorite is the Alien tool.
In your underseat bag, you'll want a spare tube, patch kit, and complete tool set. My personal favorite is the Alien tool.
Of course, you need a pump on your bike. Most pumps can convert between Presta valves (high performance) and Schraeder valves (standard automotive). Pumps can attach alongside your water cage, or on the seatpost.

Some tires (referring to the part with the tread here) are more prone to flats than others. In general, a cutaway tire is the most flat-resistant. The taller the tread, the less likely it is that a thorn will penetrate. See the section on tires.