DiabloScott

At issue here is the F. That F is the sum of several forces:
1. Wind resistance
2. Rolling resistance
3. Drive train resistance
4. Force required to change potential energy (elevation difference)

Unless you're climbing, your weight has next to no effect on 1, 2, or 3.
And if you are climbing, you'd have to specify some specific conditions to come up with a "mph/lb" number the way Sam cited, and that would certainly be non-linear over any meaningful range.

iab

Still don't get it. If I am capable of sustaining 88 watts and you say the "a" doesn't change in m*a*v, if "m" is lower, "v" proportionally increases.

DiabloScott

Weight certainly affects your acceleration... how quickly you can change speed at a constant power. When you're at constant speed a=0, so (mav)1 = (mav)2 is a trivial relationship.

The real reason people get faster on flat ground when they lose weight is because they are biologically more efficient - less blubber to sustain with their metabolism and their power output goes up. OK, I don't have science to prove that statement, just anecdote.

And the reason they get faster climbing hills when they lose weight is because it takes less power to overcome gravity.

iab

Net acceleration is zero at a constant velocity, but my massive 88 watts is generating acceleration. It is only netted to zero by friction.

If a=0, then where are my 88 watts going? p=mav, if a=0, p=0.

DiabloScott

You're not accelerating, you're doing WORK, countering the forces of friction. The more POWER you have, the faster you can do the WORK

Top end speed of a semi is the same, whether it's loaded or not. But it takes a longer time for the loaded truck to get up to that speed, and takes longer to stop.

iab

I think I got it. Thanks.

DiabloScott

Anything else I can explain for anybody? Absorption chillers? Nuclear fission?

clubman 

Ouch. Our society in 25 words or less.

Bandera

Getting the incremental improvements that matter most over the last 45 years for road racing machines seems back to front in this thread.
By that I mean:

1) A good quality steel race frame from the '70's fitted out with all modern components.

B) A modern CF race frame fitted out (not so easy to do) with a 70's period NR group w/ DT friction controls, non-aero brake levers, 52/42 5 cog 14-21 gearing, Toeclips/straps, 36H AL tubular wheels, Brooks Pro Saddle and a mechanical stopwatch & holder.

I'd race version 1 vs B myself.

Oddly enough there is an entire thread in C&V "Retro roadies- old frames with STI's or Ergos" with 1,903,083 posts indicating that this is a well trodden path.
Not so oddly for B there is Nada.

-Bandera

iab

How did Paul Newman eat so many eggs in Cool Hand Luke?

johnnyace 

I probably have what would be considered an unreasonable hatred of Ultegra, especially the brifters. I base this on:

1) I think it's butt-ugly.
2) Every bike I've ever purchased with Ultegra on it has been dysfunctional; again, especially the brifters.

SamSpade1941 

You mean more things your not expertly qualified to speak on . ?

SamSpade1941 

Pretty sure George Kennedy covered that in the movie.

Steve Whitlatch 

How much of a boost can the psychological effect of riding a brand new modern race bike bring to the table? Can that be measured? I mean, it could make some people feel better, push harder, train harder and play harder. How many people here purchased super expensive exotic Italian steel bike because so and so was super fast and won a race on it back in the day? It seems odd that we make fun of the young crowd now for buying bikes that today`s idols of the sport ride? Whatever gets them on a bike and riding is a great bike. I have given up on making fun of carbon bikes. They might not look as pretty as my steel to me, but my Cannondale sure is fun to ride.

Steve Whitlatch 

You know what else I find to be odd? The push to bigger tires on the old steel bikes? So many people here do not ride the old steel racing bikes anymore because they will not fit 32`s or bigger? But boy the old steel racers are superior or just as good as today`s bikes? The other odd thing is that I have heard over and over how some steel racing bikes are superior to other steel bikes because they are two to three pounds lighter.? But carbon bikes that are five to six pounds lighter than steel bikes have no advantage? We should start a C&V contradictions thread?

DiabloScott

Wow, four errors in an 11-word sentence... you're just trolling me aren't you?

Fahrenheit531 

This image will never leave me.

63rickert

The demographic around here seems to be 60+. How fast are we going that an aero frame is going to make any difference? When JRA means 40kph and sprints are always above 60kph fair enough to presume all present are on carbon. If over 60 and doing those speeds training and sleeping is going to take so many hours nothing will be left over for fooling with C&V bikes.

I ride old bikes because I like them. Can remember JRA at 40kph when steel was the only choice and those memories will last. Memories won't make me fast and neither will carbon.

And all my bikes will fit 32mm tires. Because they are old bikes. If your concept of an old bike is something 10 or 20 years old you don't get to play with wide tires. Which are just normal tires.

robertorolfo

Actually, what are you thoughts on the ITER project? I personally think it's the most important project on the planet... that nobody has ever heard of.

Yes, and version 1 is exactly what I did race (and I even posted it in that thread last year). I'm pretty sure I was also careful to specify the frame, and not the entire bike.

The sheer volume of Ultegra was truly shocking. You would think some of those guys would use something else just because they thought it was superior, and therefore they would have an edge over almost everyone.

It's also sort of strange to me (just my opinion), that so many people are fine with cookie-cutter bikes and parts. I mean, don't you want your bike to be your bike?


Sounds like the makings of a good GCN video: "What is faster? New frame with old parts, or old frame with new parts?" As stated, though, it would probably be a PITA to setup a new frame with vintage stuff.

BadGrandma

Bandera,, so you're obviously not a woman. Not that I would have podiumed, anyway. BTW, I think this was supposed to be a light-hearted post.

Kuromori

There's a carbon Diamondback Podium with 50th SR. That's pretty close.

Bandera

Thank you, I guess.......

-Bandera