I haven't read any other replies to this thread yet so this may have already been said. But, in my opinion. Assuming ftp and watt/kg are similar I would think there wouldn't be any difference. I would think weight is weight. Doesn't matter if its on your person or on your bike.

The people or the bikes ?

I've not heard this term and I'm sincerely curious, so I must ask. Are you calling the OP (or someone else in the thread) "home slice" or is this a term for something else? Either way, I don't judge.

On "homeslice":
LOL. No particular BF member or person at all. Just referring to a fictional "Joe Q Public". Homeslice being a term I learned growing up for someone that's an acquaintance, maybe closer, that's your buddy and you're just sitting around shooting the breeze together. Synonym "buddy".

Kind of like "hey buddy, be careful with that blow torch". Would be "Hey homeslice, watch the torch."

I've usually heard it used when you're trying to get someone's attention but not do so in an overly confrontational way.

On the bike weight thing:
I want someone who desires a 3lb lighter bike to by all means buy it and enjoy it and allow us to check out how nice it is, with pics. I just hate people being disappointed from misinformation.

People hear things like, "an ounce on the wheels is blah blah on the frame". Or "a pound of bike is worth several pounds of body". People take that stuff as gospel and then extrapolate it out.

We had a guy at work training for a hilly fondo hear this kind of thing and went out and bought a really light and super nice bike. He wasn't really pleased whatsoever with it, as it wasn't "that much faster". Like, dude was pissed and genuinely upset. We even tried to cajole him that he was still doing well and to just enjoy the nice purchase. He wasn't having it. He thought it was a POS.

Difference was, when I bought about $1500 more bike than I needed or deserved (it was a $2000 bike).....I knew I was just some weak riding average joe. I liked the color scheme, it looked freaking cool, and the components felt really nice and it seemed to test-ride fine also.

I like hearing about people happy with their bike, and happy on their bike. Not angry that the 3 lbs less didn't change the world.

It matters not whether the difference is significant, it is a matter of direction. It's often easier to work these things out as being case A or B by comparing an amplified version - In case A you have a 50kg rider and 40kg bike. In case B you have an 85kg rider and a 5kg bike. You then decide who has the easiest ride. If you arrive at case B in the extreme, then chances are it's going to be case B in the lesser extreme scenario. Of course, it may not always be that simple..

That's not helpful at all. Assuming that the riders are approximately the same size (or this is now an aero question instead of a weight one), you now have a rider who's probably well below average in strength operating a bike made out of lead. At least when the riders were closer to each other in weight and size, there was some question as to differences in fitness levels. By going to extremes, I either have to assume that one of the riders is very heavy for his size or very light, both of which possibilities will affect the rider's ability. If anything, you've just demonstrated that we don't have enough information to answer the question--we need to know what kind of extra weight the heavier rider is carrying because leg muscle might improve performance.

All other things being equal (AOTBE), if you are spinning smoothly then there is no difference. If you stand up and rock the bike side to side, as one does, then a lighter bike would be better than a lighter body. The actual amount of energy spent may not change a great deal, but you will feel the difference and the psychological effect will be greater.

As for rotating weight (AOTBE), lighter wheels/tires will accellerate with less effort, but when going at a steady speed, a change in rotating weight has identical effect as static weight.

When climbing while seated, rotating weight also counts for exactly the same as static body or bike weight.

When cruising on flat ground at a steady speed, a change in weight (body, bike, or wheels) makes zero difference (AOTBE).

What about rolling resistance? Do you think it's a hoax?

You are looking way too far into it. It's merely weights and measurements, not whether one is likely to get more vitamin D than the other...

So, in your mind, 5 pounds of additional leg muscle is exactly the same as 5 pounds of fat? Really?

What a spectacular example this absurd thread is of people's ability to argue about anything, as if it matters.

No, posting on an internet forum isn't a way to "settle an argument." But it can be an excellent way to start a meaningless argument among people who like to argue about silly things.

u
Right. The point is that the rider isn't just payload, he's the motor. It isn't just a matter of weight and resistance, it's also the ratio of power to weight that will determine speed. If you do like Mikey did and make the ratio of bike weight to rider weight radically different, it's pretty much impossible to believe that the ratio of power to weight is equal. He actually obscured the gross vehicle weight question by changing it to a puny rider pushing an absurdly heavy bike.

Just curious, have you ever looked at your own posting history?

Well played, sir! You have perfectly executed the internet forum equivalent of "But the emails," ignoring the substance of my post and making a personal attack.

I must have confused you with someone else when I said I like your posts, since I haven't seen one post that meets that description in the last couple of weeks.

But carry on with your silly arguing; you'll always have people happy to engage you. But I'll be ignoring you from now on.

Whatever additional impact there is from rotating weight, on the wheels rather than frame, it is vastly over-rated. The situations where it would be actually an advantage may, in fact, outweigh having to overcome the slightly greater inertia from the rotation. I might prefer 500 gram lighter wheels, but only to save 500 grams of weight.

Bike vs body, no difference except in how the bike handles.

Substance?

Argument: your friend is making an assertion. Your response is suppose to be a rebuttal. All you did was to make another assertion without a rebuttal. That is why this argument will go nowhere.

The rebuttal requires great physics skill. Perhaps neither of you have it and that's why you're here.

The amount of WORK being done climbing a hill will be exactly the same in both scenarios. Basically, the rider needs to move 200 lbs of total weight to the top of the hill in question. In my experience the feel of the bike under the rider will be drastically different when comparing two bikes 5 lbs apart, but that won't change the scenario being discussed though.

The wheel question is more difficult to answer. Light wheels are an advantage when accelerating the bike because there is less inertia. Once up to speed the difference is a wash, or maybe in favor of the heavy wheels since they will hold speed better.

My thought exactly.

I'm not trying to convince anyone, but I'll take the lighter bike.

Why not do both? Lose weight and get the lighter bike.

I moved into to Pro XC class at 148 lbs, and I was finishing nearly last every race. I put on 5 lbs. of muscle, and started riding farther and faster than I had ever done before.....and on the same 19lb. bike. So if you can lose fat and not muscle, that's great. If you're losing weight through muscle loss, I'd have to reiterate, I'll take the lighter bike.

Good point--I was arguing above it depends on what the 5 pounds off the cyclist came from.

I don't know how tall you are, but it sounds like you probably couldn't lose weight without losing muscle power.

Is upper body strength a bigger advantage in xc than other races? I actually got faster last year losing upper body muscle, and since I don't race, I've decided that's not worth it to me this year.