I am not at all sure I follow your logic. If not for 9/11, we'd have none of this security theater nonsense. People born post 9/11 are affected by this even if they were not around on 9/11 (and relatively few people were directly affected -- closest I get is multiple friends-of-friends, and I live in a Boston suburb), and it may cause them to change their travel preferences. Most people experienced it only on television -- is there a difference between seeing it live, versus on video? It seems like you are make a fine distinction that is not necessarily justified.

I think you need to explain to this poor dumbass how air resistance has any effect on using the tachometer (that's engine rpm) to estimate speed when the speedometer has hit its limit. Normally when you hold the gear constant, especially with a manual transmission, you can observe an exact correlation between road speed and engine rpm -- for example, "speed in kph = revolutions per minute times .045".

I don't understand why you would only count deaths of people alive on 9/11 -- if some sort of idiotic cultural reaction to 9/11 resulted in a permanent increase in early deaths, that effect applies to people born afterwards. These events are not single-points of change -- we still have our rainbow alert system, we have all the security theater at airports to remind us that Evildoers might want to sneak onto airplanes, etc.

They make my head sweat, quite a lot, even in the (20F) winter -- on a bike. No physical activity in a car, hence the main objection I have is removed in that case.

The other problem with bicycle-helmet-smiting is that it is not rational nanny-state behavior; it is far, far more sensible (which is not to say that it actually comes anywhere near "good idea", it is merely a less awful idea) to withhold medical treatment for heart attack, stroke, and diabetes from people who don't ride bicycles -- the yearly mortality rate (not the sickness and chronic medical cost rate) is 39% higher for the non-bike-commuting population. That's a much bigger effect than crash risk. If you mandate helmets but don't do anything about the lack of exercise, all you've got is innumerate moralizing nonsense.

Though I think all the groaning and moaning about automatic speed limits is amusing, I do agree. It's much more important to enforce the low speed limits in residential areas than it is to enforce the high speed limits on highways. At the same time, you're going to be stuck with speed differentials on the highway, no matter what, and one thing that speed limiting equipment would do is reduce them -- though you would still have the slowpokes, you would not have any autos driving above the limit. By your logic, that should increase safety, right? (I know that's not the conclusion you were after.)

You can use the tach -- if 2000rpm gets you 90kph, then same gear at 4000rpm gets you 180kph. Yeah, I know, math is hard.

But the same should then also be true of driving without a helmet -- as many safety devices as cars have, they still manage to be the largest (US) source of fatal head injuries, and 23% of car occupants who die in crashes only suffer head (major) injuries. Another 18% die from a combination of head and thorax injuries.

Biking's just not that dangerous, compared to lots of other stuff we do already and think is quite safe. It's about twice as dangerous as driving per trip, maybe less dangerous per hour (one old study, from Failure Analysis Associates concluded that) and far safer than riding a motorcycle (per-trip, 25x higher risk). The health benefits are also substantially larger than the crash risk, probably somewhere between 5x and 20x.

And before you claim that my figures must be buggy -- how sure are you that your gut-level "it will never happen to me (in a car)" estimates are correct, versus risk factors compiled by health and safety agencies? And the "but I don't drive drunk or at night, therefore my risks are lower" adjustment to risks -- you think that drunks in the dark aren't disproportionately represented in bicycle fatalities?

I think that depends where/how you ride. I see flags on recumbents often enough.
What they have in their favor is better stopping ability (reduced chance of a flip).

You should probably get fitted, or at least read about it. Almost all of the books I've seen give about the same decent advice. The 90%-effective saddle height rule is that if you put the heel of your foot on the pedal axle (not the way you normally pedal) at maximum extension your leg should be dead straight -- no liftoff, no knee bend. That tends to maximize efficiency, power, and knee life. And your normal pedaling setup should have the balls of your feet over the pedal axle, more or less. If you catch yourself shifting from side to side when you pedal, that's too high, knock it down by 1/4-inch increments till you are happy. A little less height than the rule-of-thumb "optimum" is no big deal, but you want to avoid having your knees bent too much. I'm also assuming you are 6' tall or more, in which case there is no need to worry much about crank length (once you adjust gearing for reduced leverage, shorter cranks, e.g., 165mm instead of 170) are slightly easier on your knees. Tall guys with good knees sometimes go for 172.5 or 175.

Other rules of thumb -- too high is bad for your hips, too low is bad for your knees (plus you'll get serious burn in your quads).

Once you get close and find your happy place, you'll find that a millimeter here or there will make a difference -- the saddle tilt should be just so, the seat height, etc.

And if your knees are dicey, aim for a lower gear -- not spinning wildly, but back off from mash-mash-mash-mash. I'm 53, some days my knees feel a little off, I baby them till they are warmed up. Also, keeping them warm on cold days is a good thing.

I'm lucky enough that all this works like physical therapy for me, but if it doesn't work for you, find a professional. And you may have the sort of knee problem that cycling doesn't help -- those are not common, but they happen.

You might try "Lake" shoes. I have a hard time making sense of their size charts, but some of them seem to come in size "50" which is equivalent to 15. Be careful which one you select -- $ome of them are $omewhat $pendy. They're pretty nice -- I bought a pair of winter MTB shoes back when I thought cleats were important (the price is breaktaking, but they really are nice, and the lifetime warranty on the Boa laces is legit).

Or are you looking for toe clips? I think you could fit clipless on an exercycle -- that's kinda non-standard, but I am in no position to throw those stones -- and use bike shoes to click in (to "clipless" pedals, of course). One thing you might consider is quick-release pedals so you can swap them out -- MKS EZY, you can easily get clips ("Cube") and rat trap ("Promenade"). The one you probably want for non-clipless is MKS EZY Rezin, apparently only available from UK ( http://www.sjscycles.co.uk/mks-resin-ezy-detachable-pedals-prod14015/ )

Yeah, and guess how you figure out "did it right" from "did it wrong". Hindsight is a wonderful thing.
"Right" varies from person to person, and over time for any given person.
Stuff I did as a kid would rip tendons now, no telling what it would do to the joints.

The standard biking answer to "bad back" is get a recumbent, though I've never been able to get that enthusiastic about one myself (my back is not bad, but there are various engineering and safety reasons why a recumbent should be "better").

That is not, however, the case for most fat people in the US, and there are some cases of quite-fat people who decided to lose weight and did so. See http://www.bicycling.com/training-nutrition/nutrition-weight-loss/i-lost-320-pounds-riding-bike?page=0,0

On the other side of the argument, I find that my weight (220lbs) is surprisingly resistant to change. I like to eat, and the more I exercise, the hungrier I get. Doubling the exercise moves the set point down about 5 pounds, and it was 15-20lbs higher with no exercise (and that was 7 years ago).

And the professional sports guys have ruined things for the rest of us. Pushing your hematocrit up like they did is nuts (there were guys in Europe dying in the sleep from too-thick blood clotting), but a 10% nudge in my CV capacity would be right nice (though I am nowhere near anemic).

Awesome how many commenters, instead of thinking "aha, font problems!" leapt to the conclusion that you could not do math, nor did they have the faintest idea how poisonous lead really is.

Just tell all your friends to get vaccinated instead, and rely on herd immunity.