5. Glasses over the helmet straps or under?
However Lance wears them is a defensible position. Presently, the fashion is over the straps.
6. How many tubes should I bring on a ride?
Two tubes is the perfect number. You'll need one to fix the only flat you'll get today, and you'll wave the second one at the jerk who never brings his own spares—or only brought one and punctured a second time.
Wave the tube, but never offer it—the only thing you should leave an unprepared rider with is a memorable lesson. Also, many of us forget to repair or stow a punctured tube and bring it along for the next ride. Having the second is a godsend in such cases.
7. What things should I check before every ride?
Always check the quick-release levers. Open them a little less than half way, not so far that you mess with the wheel alignment, but enough so you can check that they close tightly.
Next, check tire pressure—always ride the same pressure so you will be able to trust your bike in the corners. I spin the wheels to check for brake drag, cuts in the tires and wiggly rims, quickly put the front tire in between my knees and twist the stem to ensure it is tight, and then squeeze the brake levers to ensure that the pads hit the rims at the right place. If I am using tubular tires (I almost always do), I grab the tire at a random point and roll it on the rim to ensure that it is securely glued, and then I ride.
8. How much air pressure should I run?
Every tire has a sweet spot where it rolls faster and yet absorbs road shock—and more pressure is not always better, as many believe. Three features determine where this mythical tire pressure should be set. First, check the ratings on the tire. Some are rated as high as 220psi and others as low as 125psi—usually there is a high/low range, and the best place to begin is the middle.
Second is the diameter of the tire. Smaller-diameter tires (19mm) require significantly more pressure to support the same weight when compared with a larger-volume tire. 100psi may be more than ample for a 25mm casing while a 19mm TT tire will run almost flat at that pressure.
Third is rider weight. All you need is sufficient air pressure to prevent unnecessary tire flex, and not so much that you bounce all over the road on rough pavement. Riders in the 200-pound range will discover that they can get a smooth, efficient ride at close to the tire's maximum rated pressure, while a 105-pound female or junior rider may achieve the same performance near the tire's minimum pressure rating.
Any time your bicycle bounces, you are trading horizontal momentum for upward acceleration that is never recovered. What makes a pneumatic tire efficient is that it deflects over objects it contacts without lifting the mass above it (you and your bike), and as it rolls over the object, it springs back and returns most of the energy it stored as it rolls over the back side of the object.
This happen billions of times in a day's ride, so if you use the correct tire pressure, you can save gobs of energy in the form of better rolling resistance. Too much pressure will rob your strength—especially if you are a lightweight rider. If your bicycle bounces, release five or ten ounces.
9. How often should I upgrade my helmet?
Replacing your helmet once a year is probably reasonable for a high-time cyclist (2,000 miles a month), and the rest of us should consider a replacement after two years.
Crashing is a different story. The closed-cell foam that protects your head is a one-time deal; once it has been compressed, it will not dissipate the shock as well the next time. If you crash hard enough to scar the shell, you should buy a new helmet. Six seconds in the hospital emergency room costs more than the best helmet made—don't sweat the price.
10. How many CO2 cartridges should I carry?
If you run tubeless tires, carry two, because you'll need one sometimes to get the tire bead reset and may have to use the second to pressurize the tire. If you are unsupported and competing in a road race, carry two—use one to inflate the tire and the second as a backup in case you mess up the first try.
All others should carry one cartridge and a tiny hand pump (Lezyne makes the best ones). I only use CO2 cartridges when I am in a time crunch—like a race, a training ride or group situation where others are waiting for me to fix a flat. CO2 fillers are foolishly wasteful in an environmental sense (although they are recyclable), and a hand pump can refill a thousand tires without running out of air. Before you reach for that steel cartridge, consider a hand pump.