Hey, I'm a newbie...so this is new and fresh to me. ;)

An honest question:
Would a lighter bike going downhill into a head wind still be faster than a heavier bike under the same conditions?
Eh, that might actually be a dumb question...still, I don't know the answer and I'm curious.

Who are you?

That's quite the philosophical question..

I suppose I am defined by many things: my job, my family, my hobbies. But to say I am only a summation of those characteristics wouldn't be fair.

Because you see, life has a funny way of teaching us more and more about ourselves as we continue to move forward much like a roller coaster confined to its tracks.

I can certainly say I am not someone that keeps a height/weight chart handy for frivolous internet battles, ready to assert my dominance over others by the mere achievement of simply not being fat.

I can't do your question justice today -- but I hope to provide a sufficient answer by the time I draw my last breath.

I hoped or feared the response to this was "I am that I am".

In selecting a particular bike with a particular weight, you're selecting a constant rather than a variable. And this whole discussion is a simple math problem.

rpenmanparker is correct, except that he forgot that the heavier bike is faster when going downhill.

Ahhhh...I saw the light this morning.
I wasn't looking at each case in isolation - yes, the lighter bike should always be faster. :thumb:

Yeah, I realized the error of my ways this morning. In the shower, of all places. :lol:
But I guess you didn't really have to know that.

You're too fat for this sport....

I'm surprised that this video hasn't drawn any comments. Here's the empirical evidence of a speed gain that Lazyass demanded... yet he's silent. And where's 69chevy telling everyone that these two cyclists would have gained 4 seconds on the dowhhill section so it would be a wash. Why aren't they explaining that the 35 seconds over 8kms is a negligible, zero gain. I mean the video actually has the title "Real World Test" on it!

The heavier bike will be faster downhill even in most headwinds, but that difference won't make up for the time lost on the uphill...if there was an uphill...or will be one later.

It counts a lot....most important thing in biking.

You ever think that maybe weight is such a big thing because it is easily measured and quantified? Marketing people love it because they don't even have to wax lyrical to get the point across and they can just post a number. A little bit harder to do that about things like ride quality and comfort...those kinds of things take adjectives and fancy writing to describe feel and awesomeness.

GCN, while making great entertaining videos, ones that I love to watch (Matt is hilarious), is actually a marketing company.

Once again, the issue isn't whether a difference exists...it's whether that difference matters. It's a subjective argument.

It really is a stupid argument to take seriously.

Best thinking done in the shower without a doubt. Though once back in a screwball honors calculus class we had take home exams (they were THAT esoteric) and I couldn't get the last proof. Did the first four in an hour and worked on the last one for nearly a whole day with no success. Tried everything I cold think of. Then on the morning the exam was due I was spooning some cereal into my mouth thinking absentmindedly about the problem when this incredible light bulb went on. Only way to describe it. I got up from the table, went to my desk and wrote out the proof in about five minutes. My cereal didn't even get soggy. ;) Nobody else in the class got it. The power of random thinking.

Sure, I agree with that. At least from the supplier side of the relationship. So maybe I've been brainwashed, but I do love me a light bike.

For those who have not yet seen the light (see above), here is another way to look at it:

The instantaneous speed of a bicycle can (correctly) be expressed as the sum of several velocity terms which can be expressed simply by capital letters:

A + B + C + ... + W = V where V is velocity and W is the term having to do with total weight of the system. We can specify that there is another term for rotating weight, but let's just leave that alone. All the other terms can be positive or negative and relate to wind speed and direction, power output of the rider, rolling resistance, and on and on. Yes velocity is affected by all the other terms, but the W term is what it is and contributes more or less speed to the total. So if A is high one day and low the next and so on for the other terms, yes they can confound the total V and make it hard to see the effect of W. But the W term is always contributing the weight related aspect of the total speed. If W is higher due to less weight, then that contribution will be in V as more speed or the opposite if the weight is higher. Just because all the other terms make it hard to see W, doesn't mean W isn't in there representing higher or lower weight.

You're on fire today! I trust you won't be consumed. ;)

This debate has not centered on whether it matters. Those that believe the speed gains don't matter turn that around & say that because the gains don't matter to them, they don't exist. And you're right, that truly is a stupid argument.

Well, would a lighter bike stop faster as well?

Same brakes, wheels and tires, yes. Or you could build an equation for that too with all the contributing aspects represented, one of which would be weight. The weight contribution would always be tending to lower the total stopping distance, but you might not see it if the road were slippery or the rims were wet or the brake pads were glazed, etc. Same situation.

Alright, enough of this silliness. Find some other mundane topic to discuss ad nauseam.

You guys really know how to mistreat a dead horse.