I don't know if weight "really matters", but I do know that my 17 pound road bike is a lot more fun to ride than my 27 pound hybrid, when the weather abides.

It feels the same if I loaded my pannier with stuff as compare to the same bike unloaded. It does make a heck of a difference when I have to carry it up some stair. My back thanks me for the lighter bike.

What does makes a significant difference is my body mass. If I am able to poop the excess load before a ride, that little bit of weight makes a hell of a difference in my comfort level and I can ride better Haha.

We have a cargo bike, which is a 1990s hard tail mountain bike with an Xtracycle extension. It weighs roughly 35 lbs. When I take it to the grocery store and fill the panniers, it holds about four sacks of groceries and a couple gallons of milk, call it 50 lbs of stuff.

The weight makes a huge difference. Even on flat ground. The bike handles more slowly, is harder to balance at a stop and at slow speeds, you accelerate from stops more slowly, and braking is compromised. There is no way you could fail to notice the load on the bike.

When I come to a hill, the extra 50 lbs puts me a full chainring lower.

What I am saying is, I am surprised that the OP doesn't notice any difference from a 30 lbs load on his bike. Either the load isn't really 30 lbs, or he and his bike together weigh a very large amount so that 30 lbs is a minor percentage increase, or he is riding slowly in a low gear on fairly flat ground, or he is quite insensitive.

...so, if I'm just maintaining an absolutely constant speed (no momentary acceleration or deceleration) against the wind (and ignoring the small effect of mass on rolling friction for now), how does changing the total mass of the bike+rider+payload affect the net aerodynamic friction that I need to oppose in order to maintain constant speed? For argument's sake, let's suppose that the variable mass for this experiment has no effect on aerodynamic friction, for instance, filling the handlebars with lead shot, and/or inserting slugs of lead into the seat tube. Let's also suppose, in order to maintain absolutely constant speed against the wind, that I've developed a pedalling technique that has constant torque throughout the complete crank rotation. Or, if you prefer, replace my pedalling with an electric motor that supplies constant torque.

A lot of the river/play boats (Think Jackson Fun) have a weight where people below will find the boat a little more forgiving and people above will find it a little edgier/play oriented. And almost all real boats have a weight range where they are most effective.

No. I'm simply saying that the headwind disrupts your constant motion and slows you down as it opposes your motion, as you "attempt" to maintain a constant speed. In order to attempt to maintain a constant speed while a variable headwind opposes your motion, requires that you apply a continuously variable force, as you try to maintain a constant speed. These variable applied forces translate into changes in velocity. The change in velocity, by definition is acceleration. Inertia opposes acceleration and is mass-dependent.

i was also thinking about them dug out canoes made from a old tree they have to weigh like 400 pounds .

there is more rolling resistance when you're weighted down too.. i'm not sure how much but you can feel it

this is also true for terrain (it's never perfectly level) and usually also varying traffic conditions. basically, a bike is never truly traveling at a constant speed

Yeah, but they're carrying it in way that is (mostly) well-distributed relative to their muscular system. If I gain five pounds, I'm unlikely to notice it as I jog down the street. If I put on a five pound boot, I'm going to notice that.

I think something similar is at work with bike weight. I realize that a bike that's five pounds heavier won't actually slow me down all that much, but it will most certainly feel different as I ride it. Of course, if your bike is a tank to begin with it's still going to feel like a tank with a bit of a load, so beyond a certain point a little bit of weight probably doesn't make a difference.

In this case, the axiom of mind over matter applies: If you don't mind, it doesn't matter.

i figure ill be happy with any bike at any weight long as it dont break down on me i think my new moutian bike is 32 pounds it is a 29er with disk brakes.but man it sure is heavy for what we payed for it

^ *giggles*

As a lighter person (115 lbs), I can certainly feel the difference between my 17-lb road bike and my 35-40lb (with fenders, racks, studs, etc) LHT. Loaded up with 30 lbs of gear, I'm hauling a good 60% of my weight. I sure do not go up hills or accelerate quickly.

On the other hand, my terminal velocity on the road bike seems to be around 55 km/hr. The loaded Surly can hit 65 (on a nice safe downhill-uphill valley), and I can't see it being more aerodynamic. It's frustrating to pass 20 odd people going up a hill during a triathlon, only to have them fly past on the downhill...

yes

I find that the bikes weight matters to me when I'm carrying it up & down stairs at work. Well, the actual SIZE is more issue than the weight. I have to carry my ride up & down on a train station,...it's made worse depending on time of day.

Weight, for me, doesn't mean all that much.

AHA!
so thats what this thread is Really about.
Feeling insecure about a new heavier than expected bike.

well, it's a 29er, what you expect? big tires = big weight
also, 29er's are the new big fad, so of course they cost a bit
I'd prefer 26" wheels myself, lighter, easier to accelerate and climb.


(caveat, they don't make 29ers in my size, so I'm biased)

To the OP's questions. Does weight really matter? Matter to what? efficiency, speed, or for enjoyment?

I wish I had taken physics in school. The efficiency discussion above is interesting yet confusing to me. I guess what matters to me is having the right bikes for the right applications regardless of their weight is what makes it all fun. I'm no weight weenie, but I'll admit that I don't want my bikes to be heavier than they need to be.

I have just as much fun riding my 17lb CF road bike 100 miles as I do my on 35lb Fat bike riding 10 miles in the snow or dirt. It's fun to be able to load 20 lbs of groceries and a couple of growlers on my Commuter bike and get them home. It's fun to cruise around the hood on my old 40lb Schwinn speedster, It's fun to mountain bike on a 25lb hardtail. They all do what they do really well, and it's all pedaling which is what I like.

I have a dedicated commuter bike but, I can and have commuted on all of my bikes. Some go a lot faster than others, but I enjoy them all for what they are.

i thought that going from my ultralight fixed gear to a commuter with bags/fenders/lights/fatter-slower tires/etc. would be a downer, but (as w/ the post above) it hasn't lessened the fun and satisfaction.

i'm conscious of the added weight and time, but it's appropriate to the tool....