waterrockets 

I would like someone to demonstrate, or link to such demonstration, that a stiffer frame is faster -- like for racing. I'm talking about stiffness resisting pedaling deflection (BB shell, stays, head/seat tube orientation). My current belief is that it's a myth that won't die. I don't dislike stiff frames, but I don't see why there would be any advantage whatsoever -- maybe minor tradeoffs, but no advantage.

We'll assume a flexy frame is at least stiff enough to prevent chain rub on the front der. I can appreciate a preference for the stiff feel -- which could increase an individual's comfort enough to ride faster, but that's the rider, not the frame.

I'm looking for engineering and physics here. I'd like to be educated if I'm wrong.

Arguments like "that's what the pros ride" and "the bestest bike maker EVAR makes stiff frames" will not be considered.

botto 

maybe. discuss.

shakeNbake

Faster riders are faster. Discuss.

BananaTugger

Dis... cus?

Grasschopper

Ok well it looks like no one actually wants to discuss this.

Personally I think it depends on the riding style...a spinner doesn't need a stiff frame and probably doesn't notice it at all. Personally when I get on a Cannondale I can feel the difference...hell I can even feel the difference between my Roubaix and my Merckx...the Merckx is stiffer for sure (same wheels/tires). On the Merckx or the Cannondale when I get up and hammer it feels like all of that power is going to the ground...on the Roubaix it doesn't feel the same at all. Now the Roubaix is comfortable as all getout and if I am spinning away it just doesn't matter...but when I stand or mash I can feel it.

Now is it really faster? I am not sure...but the last test ride I took on a C'Dale gave me a best time for a standard loop. Was it good legs that day or did the bike play a roll? Now if it was a ride I had done a couple of times I might be inclined to think it was good legs and high from being on the new bike...but I have done this loop a hundred times or more and on several different bikes...the Cannondale was the fastest by several min and nearly 1 mph in avg speed. It didn't make me a racer but I do feel it made me faster.

badkarma

Well if your frame is flexing, then that's lost efficiency - some of the energy you put into pedaling is being lost to frame flex.

The amount of speed lost to frame flex is probably somewhat negligible - but it'd be an interesting experiment.

Jarpmann

where does the energy to flex the frame come from? since its comming from you i dont see any reason that a stiffer frame wouldnt be faster. unless you want to call the frame flexing a conservative force... but i would tend to think that i would not be a conservative force.

EDIT: beaten to it..

query

Bianchi is the bestest bike maker EVAR, and they make stiff frames.

badkarma

Pointless post :yawn:

botto 

You can teach Rocket Science, but you can't teach irony.

redfooj

law of thermodynamics states: red italian bikes are faster

KinjaBoy

Post of the day.

slowandsteady

Stiffer frames are faster. Just ride a mountain bike with a full suspension for proof. But, that said, is the difference from the flexiest road frame to the stiffest road frame enough to be statistically significant....who knows.

indygreg

but damn if Alanis Morresette did not try.

shakeNbake

True dat!

I saw it once in a movie, you can draft behind an 18 wheeler up to 60 mph.

pelotonracer

You idiot, obviously black German bikes are best!

urbanknight

If you've ever ridden a poorly built frame that feels like a wet noodle, you'd know the answer.

Now for my serious answer, I will say that a frame could possibly be "too stiff", especially in endurance events. If your body fatigues from road bumps, you also lose energy. The trick is finding a bike that is stiff enough to transfer your energy to the drive train efficiently, yet forgiving enough to keep you from losing concentration because of your sore @$$.

Oh, and celeste paint makes frames stiffer than red

merlinextraligh

However, to the extent the frame rebounds, the energy isn't lost, except to the extent of energy lost as heat in the process. Thus the amount of energy lost in frame flex that could be converted to speed has to be incredibly negligable.

I do think there are some perception things going on that may make a stiff frame feel faster, and may possibly even make the rider ride faster due to a confidence or motivational affect.

Switching from my Merlinextralight, a relatively flexy frame by current standards, to a 2007 Giant TCR Advanced Team, a very stiff frame, The Giant feels like pushing on the pedals gives a more instant response, whereas the Merlin feels like it doesn't accelerate as fast initially. The positive feedback makes it feel faster, and possibly inspires you to ride it faster.

Also I've noticed in fast descents, the Giant seems to carve turns better, and feel more secure in high speed turns. I attribute this in part to the stiffer frame. (Although I'm willing to consider that it may well be in my head). My confidence in the line carved with the stiffer frame gives me the confidence to corner faster.

redfooj

black = absorb light = waves = energy = heat = flex = slow

badkarma could tell you that

Bob Ross

Correction: celeste paint makes *riders* stiffer than red

pelotonracer

Not when you have a former Luftwaffe engineer working in the depths of the Scott laboratories making carbon cloth thinking that he's working on a V222 rocket to extract some revenge on the Brits...

SBSpartan

All I keep reading is blah blah blah.

Ok, except the guy who made the stellar reference about the semi truck. That was nice.

merlinextraligh

And your addition was?

botto 

speak for yourself.

bbattle

Ride a bike with underinflated(flexy) tires. Then ride one with properly inflated tires and see which is faster. A stiffer frame will be faster, to what extent depends upon the degree of flex, the type of flex, the rider, the ride itself. Unless you want to go really fast while in North Texas, I wouldn't worry about it.

And everybody knows that orange bicycles are the fastest.