The terminal velocity of someone FALLING through the sky at sea level density with your body spread out at the max coeff. of aerodynamic friction is 120 mph or so.
Going head first, you might reach over 250mph. 20 miles up in thin air and you might reach 6-700mph.

The world record for someone on flat ground drafting behind a car with a flairing on the back is over 160mph. So on flat ground, on a slowly accelerating truck, 40mph should be no problem in the draft.

Plus as speeds build on the truck, you get the added advantage of that low pressure sucking you forwards.

My worst fear in drafting a truck is going too fast. If he jams on the brakes, I'll be eating bumper.

Do people actually do that? It sounds wildly fun and dangerous.

I'd like to try it.

When you're riding in nyc, that's just about all you do.

How long would it take without drafting?

thanks for the help guys, i know i'am asking some stupid crap

When I was a kid, I had a friend hold onto the rear view mirror of a car while going down the road on his BMX bike at 40mph. Lost control. Not much skin left on his arms and legs afterward. He's lucky he didn't end up getting run over. To this day, he admits the stupidity of it, vastly outweighed any rush he recieved. The rush of blood was much more noticable.

Ok, serious answer: Most people probably can't, unless their drafting or descending.

LOL....

yea, i ment downhill

Well, the most important thing would be reducint aerodynamic drag, since at that speed, the drag is gigantic.

And a hill. You'll need a big ass hill.

And brakes. You'll need brakes.

That's pretty much it.

You will be surprised to find you don't really need a huge hill. Of course this depends on what you consider a big hill. Around me I regularly hit 40MPH descending 6% grades that are about 1/4 mile long.

Time to whip out the ol' kinematics text book, 15% grade downhill for 30 miles with a 10mph tailwind. How fast are you going?

Not fast enough. Where's my prize.

The 10mph headwind is what kills the mph.

whats headwind ? lol

also, i know i must be aerodynamic, so hunker down, lol what else could i do for the bike to decrese drag?

thanks

Headwind? It's the air blowing through the cavities in your skull. Some people have more of it than others.

55/Rad

so coulden't i just wear a full helmet to decrease headwind ?

also whats the best way to make a mnt. bike faster?

thaks

What.. headwind... ok I changed it to tailwind lol.

hey, anyone think they could take a 50 something dollar walmart bike to 40mph?

I could. But then I'd open the tailgate and push her out.

55/Rad

haha

also, what would a Crotch Rocket moto style fairing to for bicycle top speed??

lol, no... but my $50 Magna goes up to 30MPH on a sprint Yeah, them department store bikes suck.

Deflect more wind into your head. See "headwind" definition up a few posts.

Keep 'em coming - this is fun.

55/Rad

Catapult.