Bicycle Maintenance Advice
There are plenty of books and sites cover the topic of bicycle maintenance. Rather than reiterate what's already been written, Here I'm going to add insights and perspectives that I've discovered on my own.
Presta vs. Schrader
Presta valves are fragile, and therefore trouble. I've been riding most of my life, often putting on a few thousand kilometers a year. Most of that time, I had Schrader valves, but for the first few years on my Haluzak Horizon, I had Presta valves. In those few years, I had more broken Presta valves than I've had broken Schrader valves in a lifetime.
The issue is Presta's lock-shut mechanism. There's a tiny screw in the center of the valve, with a captive nut that is tightened to lock the valve closed when not being inflated. To inflate, you must loosen this screw and retighten it afterward. When inflating, you apply the pump over this. If along the way, you bend that screw--and it's easy to do so--then it's just a matter of time before you need a new tube.
Some argue that since Presta valves tighten to the rim, when using a handheld pump, you avoid moving the stem around and breaking/cutting the stem on the rim. It sounds good, but in practice, I find being sufficiently delicate with Presta's screw harder than not abusing the crap out of a Schrader valve stem. If you're committed to this style of locking metal stems, though, Schwalbe offers them on their Schrader tubes.
Use the ISO numbers, Luke.
Did you know that 1.75≠1¾? At least, not in bike tires; they indicate different sizes. There are, in fact, at least 7 different diameters of 26" tires, 3 sizes of 20" tires, 4 "700" size tires (A/B/C/D does not refer to a width, as you might be tempted to think), 3 "650" sizes, and a bunch of others. It's a goddamn mess.
The ETRTO specified, and ISO adopted, a way to measure tires, and it's been in common use for ages. It's the optimal width in millimeters, a dash, and the precise diameter of the bead in millimeters. For example, 40-559 (a somewhat-wide tire of a 26" variety), 32-590 (a nominally wide road tire of a different 26" variety), 40-406 (a somewhat-wide tire that fits one of the 20" sizes), and 50-406 (a fatter tire that fits the same 20" diameter rims).
When choosing tires, the second, 3-digit number (bead diameter) must match exactly, the first, 2-digit number (width) should be in the ballpark. You don't need to know what kind of bike it came from, whether it's mountain or road, or anything else. Just look at the two numbers.
If you don't want to go gray, use the ISO sizes. It will make your life easier and less error-prone when buying tires.
Additionally, any bike mechanic I've met that's worth his salt uses the ISO numbers instead of the old sizes. If you're at a bike shop where they don't understand or use the ISO numbers, beware: they're probably not the best.
I've settled on Schwalbe tires. I've had all sorts over the years, but the Schwalbe Marathon tires have proven themselves to me with their durability. The Marathon Greens especially: they're intended as a touring tire, thus a little heavier, but they have a good tread and additional layers that reduces flats.
As a bonus, all Schwalbe tires have a reflective ring on the outer walls that improves visibility at night.
Also, their Schrader valve tubes feature a metal locking valve stem similar to that commonly found on Presta tubes.
Maintenance to Avoid Flats
Pick your tires periodically to reduce flats. Rotate wheels slowly and look for glass, stone chips, or other debris that's cut its way into the tire, but has yet to cause a flat. If you find any, carefully use a tool to pry it out. If there's a cut or hole left behind, fill it with Shoo Goo to keep future junk from exploiting the weakness. Note, you'll need to let your tires set overnight while the Shoo Goo dries.
Do this periodically. When touring, I aim to do it at the end of every day.
If you ride through glass, hear a rhythmic ticking sound coming from a tire, or feel a tire pulsing/bumping, pull over and take a look. Remove debris immediately, then apply Shoo Goo at the end of the ride.
Deraileur vs. Brake housing
Brake cable housing is not the same as deraileur cable housing. Brake housing is stronger, but subject to end-to-end compression under tension. Deraileur cable is weaker, but not subject to compression--ensuring shifting index systems work correctly.
Use rubber beads on exposed cable
On some bikes, cables run through housing the whole way. On others, there are spans where the cable is exposed. On these, you'll sometimes see little rubber beads whose sole purpose is said to be avoiding cable chatter against the bike's frame. Perhaps they do that, but these also deflect rain/water that collects on the exposed cable.
If you're riding in the rain, there's the rainwater, plus your tires are kicking up all kinds of dirty water. That collects (among other places) on the cable. It then follows the cable, motivated by gravity and vibration, and goes into the next housing where it causes trouble, either rusting or gumming things up. On a diamond frame, the effect is probably most pronounced along the down-tube, where the front wheel throws up dirt and gravity pulls the water down the diagonal cable and into a housing near the bottom bracket. For me, I encountered the phenomena on a similar diagonally-oriented cable on rear of a recumbent.
When stringing cable, put rubber beads on the exposed section. Position one or two near the ends, to help deflect water and keep it out of cable housings. Shifting will stay smoother longer, and brakes will release instead of stick. Bike shops rarely have these, or charge a fortune; you can buy a bag of hundreds of rubber earring backs that work well for these at Amazon or a craft store for a few dollars.
Buying a bike? Consider the brakes you want.
- Caliper brakes are trouble, often sticking when brakes are released. Center-pull calipers are less trouble, releasing symmetrically, whereas side-pulls like to go out of tune and release one side, rubbing on the other. But there are better braking systems out there these days.
- V-brakes seem to be much less troublesome, although they still require some periodic adjustment.
- I haven't used cantilevered brakes, but they look like they'd also be a big improvement over caliper brakes.
- Disc brakes feel like they brake much better, they don't lose grip in the rain, they don't wear on the rim, they don't care if the rim is slightly out of true, and they require little adjustment beyond turning the brake tightener knob as the brake pads wear down. The downside is they are heavier than other options.