Weight distribution of bike

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I know that "rolling weight" - such as wheels, crank, etc - is more important than static weight (frame, etc). However, when considering things like weight of saddle or weight of handlebars - is static weight more important toward the upper part of the bike or the lower part of the bike?

I know that "rolling weight" - such as wheels, crank, etc - is more important than static weight (frame, etc). However, when considering things like weight of saddle or weight of handlebars - is static weight more important toward the upper part of the bike or the lower part of the bike?You'll probably get some educated answers, but I think we're getting into the realm of "how many angels can dance on the head of a pin" type of tiny, tiny differences, even in theoretical terms. We've all heard the arguement that rolling weight is more important to static weight, but the real-life situation is that if there is a difference, it is hardly meaningful. In other words, 3 ounces saved in wheels vs. 3 ounces saved on the bike is theoretically different, but doesn't have a lot of practical effect.

Then we get to the question of how much static weight change is meaningful, and the differences are even less. My guess is that upper vs. lower is even less meaningful.

It will be interesting to hear the theoretical analysis though (I'm serious - this stuff is interesting even if it isn't meaningful).

If you were asking the question about motorcyles, then where the weight is distributed does count.

On a bike the bulk of the weight is your own body. What makes a bike handle is the geometry, optimised rigidity, the tyres & their inflation and how the rider positions their body and controls the bike. Weight distribution would make virtually no difference at all.

I know that "rolling weight" - such as wheels, crank, etc - is more important than static weight (frame, etc). However, when considering things like weight of saddle or weight of handlebars - is static weight more important toward the upper part of the bike or the lower part of the bike? I haven't thought about it in great depth, but at the top of my head, I would say that it doesn't matter how the static weight is distributed. The only part of the bike that is rotating are the wheels (other than the pedaling of course), and so the rotational constants that count are the moments of intertia of the wheels. So, purely from a weight perspective, the distribution of static weight shouldn't matter. Now, aerodynamics is a different matter, but it is not a simple function of the weight distribution. If any of above is incorrect, someone please do correct...

It may be "theoretical", but on a long ride, it makes a difference. In fact on a SHORT ride, there's a difference in pure pleasure.

Weight affect depends upon the circumstances - for example, a ski pole 48" long and weighing 7 oz. feels discernably different from one weighing an ounce more. In flyrods, an ounce is huge, and the difference in performance and feel of a 6 foot graphite rod of 3.5 oz. is different from the feel of an 8 foot graphite rod of 3.5 oz. And the difference between casting a fishing lure of 1/4 oz. and one of 1/2 oz also is huge.

As for bicycles, the pleasure (never even mind the performance) of riding a 15 lb. bike as compared to an 18 lb. bike is huge - at least, it has been for me, and I can't imagine anyone wouldn't feel the difference. The feeling of acceleration on a 15 lb carbon bike with really light wheels is a joy.

So far, the repsonses are minimizing the affect of weight and weight distribution and are from riders who think it makes not any significant difference. I'd like to hear from someone who really cares about it.

It may be "theoretical", but on a long ride, it makes a difference. In fact on a SHORT ride, there's a difference in pure pleasure.

Weight affect depends upon the circumstances - for example, a ski pole 48" long and weighing 7 oz. feels discernably different from one weighing an ounce more. In flyrods, an ounce is huge, and the difference in performance and feel of a 6 foot graphite rod of 3.5 oz. is different from the feel of an 8 foot graphite rod of 3.5 oz. And the difference between casting a fishing lure of 1/4 oz. and one of 1/2 oz also is huge.

As for bicycles, the pleasure (never even mind the performance) of riding a 15 lb. bike as compared to an 18 lb. bike is huge - at least, it has been for me, and I can't imagine anyone wouldn't feel the difference. The feeling of acceleration on a 15 lb carbon bike with really light wheels is a joy.

So far, the repsonses are minimizing the affect of weight and weight distribution and are from riders who think it makes not any significant difference. I'd like to hear from someone who really cares about it.I don't doubt wyat you're saying, but in my example, I was talking about the relative difference between the same amount of weight taken from wheels vs. the frame, etc. Plus, I wasn't talking about the difference between an 18 and 15 lb bike. I have no doubt that it is a significant and very fun difference. I doubt if there's much to be noticed between a 16 and 16.5 lb bike, and I doubt if there's much difference between a few ounces (e.g. 100-150 grams) lost in wheels vs. other parts... in feel or in measurable performance. JMHO of course.

It may be "theoretical", but on a long ride, it makes a difference. In fact on a SHORT ride, there's a difference in pure pleasure.

Weight affect depends upon the circumstances - for example, a ski pole 48" long and weighing 7 oz. feels discernably different from one weighing an ounce more. In flyrods, an ounce is huge, and the difference in performance and feel of a 6 foot graphite rod of 3.5 oz. is different from the feel of an 8 foot graphite rod of 3.5 oz. And the difference between casting a fishing lure of 1/4 oz. and one of 1/2 oz also is huge.

As for bicycles, the pleasure (never even mind the performance) of riding a 15 lb. bike as compared to an 18 lb. bike is huge - at least, it has been for me, and I can't imagine anyone wouldn't feel the difference. The feeling of acceleration on a 15 lb carbon bike with really light wheels is a joy.

So far, the repsonses are minimizing the affect of weight and weight distribution and are from riders who think it makes not any significant difference. I'd like to hear from someone who really cares about it.

The difference in "accelerating a 15lb carbon bike" isn't very much at all. Positive thinking, though, makes all sorts of new stuff feel fast. With the same force applied a 15lb bike and 170lb rider will accelerate 1.6% faster than an 18lb bike and 170lb rider. I didn't consider wheels, but if you want to add the differences of acceleration with different wheels, feel free. It'll only make a fart's worth of difference.

Last time I checked, 1.6% is anything but huge in this context.

I really hate to admit this because I paid quite a bit for my 16 pound road bike but since I ride so much on my Trek 4300sl for commuting purpose I have gotten very adept to it particularly whislt climbing. In certain instances the Trek is actually faster due to my gearing and standing postion on the pedals as well as my control using a more flat mountainbike style handlebar vs. a dropstyle. To add more insult to injury I suspect the Trek to way around 34 pounds with its mechanical disc brakes and Topeak luggage carrier/bungeed milk crate. :eek:

But in the defence of the 16#er, I don't ride it enough,it's still new to me and really is the lightest, stiffest, most precise bicycle I've had the pleasure of.

I'm hearing about how little difference weight really makes - and that's not what I asked about. I would appreciate an answer about distribution of static weight - higher or lower on the bike - from someone who can just answer that question: What is the relative importance of the placement of static weight placed higher on the bike versus lower?

Well, there's nothing wrong with differing concerns - but whether it's skis or bikes, I tend to be sensitive to differences. There's no question that, without knowing anything at all about bike or wheel weight, the first time I demo rode a 15 pound bike, the feeling was fantastic - unlike any bike I ever had ridden before.

As to the importance of "rolling weight" I have no doubt. Try taking some lead tape and putting an ounce extra on to each wheel. If your wheels are already far from light weight, you'll notice no difference. If your wheels are very light weight, and you don't notice a difference, then your sensitivity and mine are vastly different. I'm not a large guy - my fat weight is 16o pounds and my fighting trim is 145 pounds. Perhaps if I weighed in at 175 or if I were a Clydesdale, I'd care less about bike weight.

The time trial riders use wheels that have a more aerodynamic design but tend to weigh more than their non-time trial wheels because they basically are more interested in all-out speed over a (relatively) shorter distance. However, over a century ride, those wheels would not be optimum due to weight.

Again, I'm hearing about how little difference weight really makes - and that's not what I asked about. I would appreciate an answer about distribution of static weight - higher or lower on the bike - from someone who can just answer that question: What is the relative importance of the placement of stative weight placed higher on the bike versus lower?

Saus, re handling: despite you being so light, 90% of the overall weight is your body, so the weight distribution is about your body, there is virtually no difference in where the weight is distributed on the bike.

Weight vs Aerodynamics. At 40kph 80% of the effort is pushing air out of the way and most of that is on your body, after that the front wheel is the next point of aerodynamic focus.

This something like telling a javalin thrower that the weight of the javalin doesn't matter because the thrower weighs 200 pounds. Tell me that a pound difference in skis doesn't matter because the skier is 200 pounds. Tell me that the distribution of weight - more toward the food or more toward the tip and tail - makes no difference.

Try taking a five pound weight disc and attaching under the saddle of your bike. Ride it.

Then move the placement of the weight disc to the down tube as close as you can get to the peddles. If you don't notice a difference, then you and I can't communicate on this subject.

Where are my fellow tech weenies when I need them?!

It may be "theoretical", but on a long ride, it makes a difference. In fact on a SHORT ride, there's a difference in pure pleasure.

Weight affect depends upon the circumstances - for example, a ski pole 48" long and weighing 7 oz. feels discernably different from one weighing an ounce more. In flyrods, an ounce is huge, and the difference in performance and feel of a 6 foot graphite rod of 3.5 oz. is different from the feel of an 8 foot graphite rod of 3.5 oz. And the difference between casting a fishing lure of 1/4 oz. and one of 1/2 oz also is huge.

As for bicycles, the pleasure (never even mind the performance) of riding a 15 lb. bike as compared to an 18 lb. bike is huge - at least, it has been for me, and I can't imagine anyone wouldn't feel the difference. The feeling of acceleration on a 15 lb carbon bike with really light wheels is a joy.

So far, the repsonses are minimizing the affect of weight and weight distribution and are from riders who think it makes not any significant difference. I'd like to hear from someone who really cares about it.

It certainly may but the energy it takes to accelerate a bike is the mass of the bike and rider so....3 pounds of a package(bike and rider) that 'may' be 175 pounds of rider and 15 pounds of bike is 1.5%. It may be there, it may be huge to you but I think there are many other factors involved as to why you think a lighter bike(carbon and stiffness comes to mind, not the weight) accelerates hugely better than a 18 pound bike.

If a light bike and the joy it brings means you ride lots-that's the idea.

Obviously, stiffness and geometry - and wheel inertia - account for a huge part of acceleration. No argument. But I'm still looking for an answer to my tech weenie question, and no one has even ventured a theory.

Think of taking five pounds of theoritical weight. First, add it to the saddle. Try to imagine what it feels like. Now, remove it from the saddle and put it in the bottom five inches of the down tube. Now try to imagine what THAT feels like. Now imagine each situation over a ten mile sprint. Now try to imagine each situation over a century ride in the Vermont hills, or over AIA in Palm Beach to Miami.

If you just don't give a damn about this or believe it makes no difference, then please don't hesitate for a minute to go to another thread and leave this one alone. I want to hear from those who truly are interested in this theoretical question.

This something like telling a javalin thrower that the weight of the javalin doesn't matter because the thrower weighs 200 pounds. Tell me that a pound difference in skis doesn't matter because the skier is 200 pounds. Tell me that the distribution of weight - more toward the food or more toward the tip and tail - makes no difference.

Try taking a five pound weight disc and attaching under the saddle of your bike. Ride it.

Then move the placement of the weight disc to the down tube as close as you can get to the peddles. If you don't notice a difference, then you and I can't communicate on this subject.

Where are my fellow tech weenies when I need them?!

http://www.weightweenies.com

Oh! If it were only that simple! The site has to do with sales, not tech weenie stuff. But thanks for the effort!

Okay I just came back home from a Two hour ride, went to town and put at least 4 pounds of groceries in my milk crate. I definitely notices a difference out the saddle sprinting on the flat roads. All the wieght up high just makes the bike feel more flexy but I still accelerate about the same. That same wieght feels easier to ride with when in the saddle and not straddling the bike side to side so much.

This something like telling a javalin thrower that the weight of the javalin doesn't matter because the thrower weighs 200 pounds. Tell me that a pound difference in skis doesn't matter because the skier is 200 pounds. Tell me that the distribution of weight - more toward the food or more toward the tip and tail - makes no difference.

Try taking a five pound weight disc and attaching under the saddle of your bike. Ride it.

Then move the placement of the weight disc to the down tube as close as you can get to the peddles. If you don't notice a difference, then you and I can't communicate on this subject.

Where are my fellow tech weenies when I need them?!

Tha javeling thrower analogy isn't applicable at all because the thrower and the javelin are two separate components - launcher and missile.
The skier analogy is only vaguely applicable because of the differences in operator - equipment interface. The skier is attached around his lower leg and has to exert all control through that pivot point - even small masses getss a massive leverage.

The bike rider OTOH has pedals, saddle and bars quite nicely distributed - nowhere near as much leverage to overcome as compared to the skier.

The thing is that if we're talking about the CoG of the bike shifting because of the actual weight of the components, then their individual contribution gets so smeared out that you really need to be ultra sensitive to notice anything. Things like rigidity becomes more important than actual weight or CoG.
But sure, if you have a choice, having the weight lower is better than having it higher. Don't expect to notice anything as long as you remain seated though.

Going from a heavy sus fork(w/ lockout) to a rigid fork IS noticeable, but first when you're really throwing the bike around.

dabac, while I do not agree on what can be noticed, at least you answered the question - weight distribution toward the bottom is preferable to weight distribution toward the top. Thanks for being the first person actually to respond to what was asked.

On a road bike of very light weight, a heavier saddle will be noticed - especially over a long ride.

But I'm still looking for an answer to my tech weenie question, and no one has even ventured a theory.
How often do you want to read the same answer? Mikesbytes already answered you, twice, but it seems that you don't like his answer. So you keep asking until someone gives you the answer you want to hear?

Seriously, Mike is right, given reasonable restrictions on weight distribution, the change in center of gravity of the bike with rider will be tiny. Such small changes will not have a discernible effect on the handling of your bike. Just think about how "different" your bike handles if you raise your saddle by half an inch, which is a manipulation that has an effect on the center of gravity that is at least one order of magnitude higher than the one of switching frames and wheels around in order to lower the center of gravity.

On a road bike of very light weight, a heavier saddle will be noticed - especially over a long ride.
Nonsense. It essentially doesn't matter how lightweight your bike is, given that the rider is much heavier, and it is the system rider+bike that matters.