Wheels

artemidorus said:

I'm in the "yes, but not very much" camp on this one.

The best thing to do is to buy or build yourself a very light wheelset and use high quality tubular tyres, then compare for yourself.

The problem that I have seen with most boutique, lightweight wheelsets is the bearings. Bearings are self explanatory. Very high quality wheelsets, such as ADAs have precisely machined hubs that don't squash the bearing race, problem is...those wheels cost a bunch of mulah.

My own preference is to build the wheels myself. My present favorites are 290 gram rims running Dugast 23 mm silk sewups with Campy Record hubs and ceramic balls. With such a combination you would notice the difference over a 2000 gram clincher wheelset immediately.

Spokes count is always a problem. As one friend of mine has stated (he has his doctorate in physics), if you could build a theoretical wheel without spokes, how long would it spin compared to a wheel with spokes. Well, by inference, the less spokes the better. Trouble is, in a handmade wheel, break a spoke and the wheel goes sproing, the less number of spokes in the wheel, the bigger the sproing. So, one must consider the wheel usage, pay your money and take your chances....

artemidorus said:

At a steady speed of 25mph a gram is a gram wherever it is.

At a steady speed (i.e., no acceleration) mass has no importance whatsoever. None. As a side note, I've shown in a previous thread that in some cases more mass can be an advantage. Imagine riding along a flat road and you stop pedalling for a second (no braking, etc - just stop pedalling). You will lose more energy than if you had an extra 20 pounds of lead in your frame.

The reason is because the drag is constant, so you lose less speed and therefore require less energy to recover the speed you lost. I can show it mathematically, but my real point is that 100 grams here and there don't have a big effect. Most often it doesn't even have a small effect.

John Swanson
www.bikephysics.com

ScienceIsCool said:

At a steady speed (i.e., no acceleration) mass has no importance whatsoever. None. As a side note, I've shown in a previous thread that in some cases more mass can be an advantage. Imagine riding along a flat road and you stop pedalling for a second (no braking, etc - just stop pedalling). You will lose more energy than if you had an extra 20 pounds of lead in your frame.

The reason is because the drag is constant, so you lose less speed and therefore require less energy to recover the speed you lost. I can show it mathematically, but my real point is that 100 grams here and there don't have a big effect. Most often it doesn't even have a small effect.

John Swanson
www.bikephysics.com

That statement is simply not true. The higher the mass, the more energy it takes to accelerate it.

Mercian said:

The best thing to do is to buy or build yourself a very light wheelset and use high quality tubular tyres, then compare for yourself.

The problem that I have seen with most boutique, lightweight wheelsets is the bearings. Bearings are self explanatory. Very high quality wheelsets, such as ADAs have precisely machined hubs that don't squash the bearing race, problem is...those wheels cost a bunch of mulah.

My own preference is to build the wheels myself. My present favorites are 290 gram rims running Dugast 23 mm silk sewups with Campy Record hubs and ceramic balls. With such a combination you would notice the difference over a 2000 gram clincher wheelset immediately.

Spokes count is always a problem. As one friend of mine has stated (he has his doctorate in physics), if you could build a theoretical wheel without spokes, how long would it spin compared to a wheel with spokes. Well, by inference, the less spokes the better. Trouble is, in a handmade wheel, break a spoke and the wheel goes sproing, the less number of spokes in the wheel, the bigger the sproing. So, one must consider the wheel usage, pay your money and take your chances....

Deep section rims (and spoke count) are so much more important than total weight as to render discussions about a few grams of weight loss almost ridiculous.

bigpedaler said:

two things i would note:

1. less weight is less that NEEDS to be accelerated, also less that needs to be slowed down in a panic stop. aerodynamics does matter, esp. as they pertain to the spokes -- i had an old set of spinergys that would create drag above 18-19mph because, mainly, of the PBO spokes. they're currently on their fifth owner since 1999.

The weight differences you're talking about w.r.t. braking are meaningless.

As for the Spinergy spokes, how do you know what drag they created above 18-19 mph? How do you know what drag they created below that threshold?

ScienceIsCool said:

At a steady speed (i.e., no acceleration) mass has no importance whatsoever.
www.bikephysics.com

It does if you are climbing.

Mercian said:

You will notice that I stated, "perceived" as well as fact. It is and was the perceived value and the actual value. Or as national caliber cyclists have stated to me: "I want that extra 1%". You have stated that there is an advantage, and that is true. By how much is irrelevant, becuz it IS an advantage. You can throw out an any advantage if you want to, but it is at your peril in the peloton.

That is absolutely not the case. What you are doing is looking at weight in isolation, when things are more complex than that. Without positive acceleration, weight is no detriment at all. In fact, it's likely that the energy saved by wheels with higher moments of inertia used over long flats or descents might easily eclipse any "penalty" from their higher moment of inertia in sprints.

Mercian said:

I also am forced to ask, what exactly is your point with all this math? Do you mean to imply that the "perceived" advantage with either aero or low mass wheels is exactly that, and is of no consequence in a race? If so, maybe you should discuss this with sprinters or Tour competitors, etc. I'm sure that they will welcome your mathmatical formulas.

The point of the math is to explain some of the physical realities in cycling and dispel long held myths. Any scientist or engineer would understand that. The math also provides important tools for trade studies: what sort of wheel is best for a 12% climb; what sort of wheel is best for a flat race; and etc.

Good grief. That isn't even worth a reply. You need to do some research on mass and the effects of work on acceleration of that mass. I'm sorry, but there's a fundamental error in your logic. Incidentally, this is the error that most make when they try to use inductive logic on the man/bicycle interface. It doesn't work with equations. Not only is your basic premise incorrect, but it is impossible to take into account the human equation, i.e., muscle hysteresis (sp?) and the will to win.

Make mine light (weight) and to go, please.

Mercian said:

That statement is simply not true. The higher the mass, the more energy it takes to accelerate it.

You need to read more carefully. He said that added weight is an advantage in that it decreases how much a bike/rider combo will decelerate as a result of aero drag and the like.

One thing that is completely being ignored here is the idea that talking in absolute terms is completely useless. The numbers need context. Likewise, statements like The higher the mass, the more energy it takes to accelerate it are completely useless without context.

John has, here, on other forums, and on his website, done a very good job of putting the numbers in context.

Mercian said:

Good grief. That isn't even worth a reply. You need to do some research on mass and the effects of work on acceleration of that mass. I'm sorry, but there's a fundamental error in your logic. Incidentally, this is the error that most make when they try to use inductive logic on the man/bicycle interface. It doesn't work with equations. Not only is your basic premise incorrect, but it is impossible to take into account the human equation, i.e., muscle hysteresis (sp?) and the will to win.

Make mine light (weight) and to go, please.

Actually you're quite wrong. You're picking and choosing when you want to take into account the "human equation" and when you don't. If you need a reminder, revisit your absolute statements re: mass and acceleration. What has been pointed on John's site, at Weight Weenies by a very nice modeling and solution of a bicycles equation of motion by Mark McM, and even by myself at RBR, is that the advantage of wheels with lower moments of inertia is so small that most of the time it is impossible to discern from the intangible human considerations. The one instance in which lighter wheels offer a real advantage is when the road grade gets steep--in the area of greater than 10% or so. In that case, weight trumps aero concerns.

Last, let's go back to a little gem you offered earlier:

Quoted post said:

I also am forced to ask, what exactly is your point with all this math? Do you mean to imply that the "perceived" advantage with either aero or low mass wheels is exactly that, and is of no consequence in a race? If so, maybe you should discuss this with sprinters or Tour competitors, etc. I'm sure that they will welcome your mathmatical formulas.

Well, I guess you better tell all those pros not riding Zipps or Lightweights that they'd better stop winning--like pros riding the relatively heavy Cosmic Carbones or Ksyriums or other wheelsets--because according to your reasoning, they shouldn't be winning.

Physics is all about absolute terms, unless you want to toss out Newtonian physics. However, they seem to work the best here on Earth. Or, I'm equally familiar with Quantum Mechanics as well, but the applicability to racing bicycles seems to elude me.

Sorry, am thru with this thread, I can see this is proceeding into absurdity with the assertion that a heavy mass doesn't take more work/force/energy to accelerate than a light mass. You should tell that to my legs when I'm accelerating my sub 16 lb race bike vs my 21 lb training bike.

However, thanks very much for your info.

Mercian said:

Or, I'm equally familiar with Quantum Mechanics as well, but the applicability to racing bicycles seems to elude me.

Me too, why on earth did you mention them? Engage alienator in a reasonable debate, or concede!

Distillation of argument so far:
Drag is much more important than weight, except when the road tips up higher than 10%, at which point the total mass of the wheel becomes more important, although the rotational inertia has elegantly been shown to be insignificant.

If you disagree, argue rationally.

Funny. I think I'm the one arguing that lightweight wheels make a difference and are easier to accelerate. Wonder how you came to the conclusion that I've never stated that????

I think this thread has gone too far. For the orginator, buy whatever lightweight wheels you care for and try them out. By light, I mean in the 1200 gram range. It is possible that with an improper tire, tube and rim combination that the so-called light set, can be heavier than what you started with. Gram counting is a proper thing to do in this case.

Mercian said:

Funny. I think I'm the one arguing that lightweight wheels make a difference and are easier to accelerate.

Noone was ever disagreeing with that. Read the posts.

Mercian said:

For the orginator, buy whatever lightweight wheels you care for and try them out. By light, I mean in the 1200 gram range. Gram counting is a proper thing to do in this case.

I'd only drop that kind of money for wheels that are deep section. Cosmic Carbone at ~1700g is superior to generic shallow section wheelset at <1200g, particularly if they have fat alloy spokes, unless you'll only ever be hill climbing.

artemidorus said:

Noone was ever disagreeing with that. Read the posts.

Nope, not correct. Scienceguy argued that the difference in weight between a 1500 gram wheelset and a 2000 gram wheelset was inconsequential, that was what the thread was about. He disagreed with me. I'm the guy that says lightweight wheels do make a difference.

Trouble is, too many people jumped onto this thread and started into various different arguments. Now we are even into aero stuff and the thread had nothing to do with that. So, I think it is time to let this one die a natural death.

Do you agree?

I love scientists and engineers. The never have a handle on the big picture (and by that I mean wholistically, not 'Big Bang Theory'. 🙄😉

Okay, here's my simple unspeakable truths as I know and understand them. I say 'unspeakable' because people don't want to hear them because they think spending money on light parts will make them faster and bring them eternal life. It won't. It's all a [censored] and we know it. But hey, I like new shiny parts and so does the next guy.

1) The inefficient, unaerodynamic, completely stupid part of the bike+rider equation, is the rider.

2) The choice of one piece of equipment over another - even for the most elite athlete in the world - makes no difference as to if they win or lose. Miss a leadout by 0.01 second? You loose. Bad night's sleep? You loose. Stub your toe at the start line? You lose.

3) Despite this, any improvement in the rider is exponentially worth more than any change in the bike. The bike is only circa 5% of the rider+bike mass equation, and it's much easier to lose 1% off you than it is the bike. Put that donut down and go ride.

4) The faster you go, the more important aerodynamics is. Unfortunately the aerodynamic part of the bike+rider equation has a massive brick hanging on the top of it known as 'the rider', making any changes to bike aerodynamics small.

5) The slower you go, the more it's simply an equation of total weight vs gravity. The lighter the better. Doesn't really matter where that weight is. See "3)".

6) Never EVER underestimate psychology. There's a reason most Pros are certifiable, paranoid schitzophrenics with an 'ego problem'. It helps them win. If they have wheels that are 500g lighter than their competitors, that's worth the mental advantage ALONE.

7) Whenever you argue something like actual benefits of changing or 'improving' some aspect of a bike frame, you are, most of the time, arguing about fractions of a percent. Yeah, that's pretty dumb, but hey, what else are you supposed to fill your evenings with?

8) Even though you are talking about a fraction of a percent, when you are on the bleeding edge, all those fractions of a percent add up. Alone they're pretty meaningless.

So, in conclusion your honour, I summise that it's all important but to minute degrees, and that yes the OP will notice that 500g off the total equation. Even if that equates to a 1% improvement, I suggest that the mental as well as physical benefits - not to mention it keeps some of us in a job - makes it well worth it.

Okay scientists, you may carry on with your equation posturing and one-upmanship. 😎

Thylacine said:

They never have a handle on the big picture

🙂 🙂

(I like the cat.)

Thylacine said:

I love scientists and engineers. The never have a handle on the big picture (and by that I mean wholistically, not 'Big Bang Theory'. 🙄😉

Okay, here's my simple unspeakable truths as I know and understand them. I say 'unspeakable' because people don't want to hear them because they think spending money on light parts will make them faster and bring them eternal life. It won't. It's all a [censored] and we know it. But hey, I like new shiny parts and so does the next guy.

1) The inefficient, unaerodynamic, completely stupid part of the bike+rider equation, is the rider.

2) The choice of one piece of equipment over another - even for the most elite athlete in the world - makes no difference as to if they win or lose. Miss a leadout by 0.01 second? You loose. Bad night's sleep? You loose. Stub your toe at the start line? You lose.

3) Despite this, any improvement in the rider is exponentially worth more than any change in the bike. The bike is only circa 5% of the rider+bike mass equation, and it's much easier to lose 1% off you than it is the bike. Put that donut down and go ride.

4) The faster you go, the more important aerodynamics is. Unfortunately the aerodynamic part of the bike+rider equation has a massive brick hanging on the top of it known as 'the rider', making any changes to bike aerodynamics small.

5) The slower you go, the more it's simply an equation of total weight vs gravity. The lighter the better. Doesn't really matter where that weight is. See "3)".

6) Never EVER underestimate psychology. There's a reason most Pros are certifiable, paranoid schitzophrenics with an 'ego problem'. It helps them win. If they have wheels that are 500g lighter than their competitors, that's worth the mental advantage ALONE.

7) Whenever you argue something like actual benefits of changing or 'improving' some aspect of a bike frame, you are, most of the time, arguing about fractions of a percent. Yeah, that's pretty dumb, but hey, what else are you supposed to fill your evenings with?

8) Even though you are talking about a fraction of a percent, when you are on the bleeding edge, all those fractions of a percent add up. Alone they're pretty meaningless.

So, in conclusion your honour, I summise that it's all important but to minute degrees, and that yes the OP will notice that 500g off the total equation. Even if that equates to a 1% improvement, I suggest that the mental as well as physical benefits - not to mention it keeps some of us in a job - makes it well worth it.

Okay scientists, you may carry on with your equation posturing and one-upmanship. 😎

Heh, heh, heh...brilliant! I'd like to see someone quantify that in an equation. Bottom line, it's all in the legs and the will to win.

Mercian said:

Heh, heh, heh...brilliant! I'd like to see someone quantify that in an equation. Bottom line, it's all in the legs and the will to win.

Gee, Francis: what about the lightweight wheels?

Oh, hey, by the way....that whole "physics is about absolutes" thing, well, that was funny. Heck, it must be....what with all those truncated Taylor series used in derivations and all those other assumptions...like this term is small compared to that term.....we'll assume this goes to zero.....yeah, it's all about absolutes.

Your "absolute" theory is gonna be a revelation to physicists everywhere. You better clean your suit and buy your ticket to Stockholm, fella, 'cuz yer due a Nobel prize. I just hope you can pull yourself away from that all-knowing Boeing computer.