rsbob 

Then do it in zero gravity and any combination will be fine.

Atlas Shrugged

Although wonderfully presented sadly these myths predate logic and are deeply rooted.

PeteHski

It doesn't help when you get bike reviewers saying how they can "feel" the improved acceleration of lighter wheels, when they are just a few hundred grams lighter. Plus they often assume it's mainly due to rotational inertia rather than just the extra bike mass.

Shadco 

How much longer until Spring?

.

Steel Charlie

I'm an antique slug. I don't race anyone and don't pretend to be "training". I prefer light wheels cos they make the bike feel more responsive and I like that. Makes my rides more enjoyable. And that's all that matters to me.
Ride whatever for whatever reason. If it makes you happy that's all that really matters this side of the TdF.

Fredo76

They had bicycles in ancient Greece?

Fredo76

It helps remind people that their feelings actually count, and that there is more work to do on the 'model'.

genejockey 

Routed?

Atlas Shrugged

Probably not, but the these silly old beliefs are somehow imprinted on a cadre of older riders who frequent these forums. From the effect of lighter wheels to not participating in marital relations before a big ride we have learned a lot over the past 50 years.

tomato coupe

They had routers in Ancient Greece?

genejockey 

I've had bicycles covered in ancient grease.

PeteHski

There is no more work required on the “model”. It already includes wheel rotational inertia. You just don’t like to hear the result that it isn’t important - not even at peak acceleration in a sprint. Or are you going to argue that Newton’s laws of motion are incorrect?

venturi95

Mister Hski, you have worked in F1, and thus you are one of the few people who I might envy. To be perfectly clear: I have a degree in a physical science (geology), a year of physics (only trig based), a year of calculus, and some graduate classes. I believe in science and physics and the power of numbers. I have competed in over 100 mass start events, and have won the Mt. Tam hill climb (as a lowly Cat 3), was first over the top (easily) at Mount Hamilton, got invited to join an elite amateur team, etc.,etc. I have very little natural ability, any results I got were from training as intelligently and as hard as possible. I'm no dimwit stuck in the past, I agree with everything you are saying except for the real-world example crudely illustrated in the following scenario:
The Old Dullard and the Talented Engineer are equally strong and fit racers, and now their race takes an upward course. The Old Dullard is on his climbing wheels, with crappy old 28 spoke sew-up rims like these
Pity poor Old Dullard, I'm surprised he can even get from point A to point B on such equipment. Now look at the Talented Engineer, he has a modern deep section carbon aero rim (460 grams vs 290 gram sew-up rim). Let's assume all the tires in this scenario are in the 230 gram range, or whatever. The average grade is only 7%, but there are some steeper and shallower sections, as you encounter in the real world.
The Old Dullard attacks on the climb and puts some distance between himself and the Talented Engineer. Now the Talented Engineer is thrice ****ed because:
-He is behind
-He is moving slower
-His bicycle doesn't accelerate on a climb as efficiently.

Fredo76

The work required must lie in the simplifying assumptions, then. They are too simple.

The snider you get with your "Because..PHYSICS!!" argument, the lower my opinion of you becomes.

tomato coupe

No offense, but one year of physics means you've barely scratched the surface.

Good story (fable?), but physics indicates that situation isn't realistic.

tomato coupe

The problem with discussing physics on a forum like this, is that quite often someone with a minimal understanding of physics is the most vocal debater of someone that does understand physics. The latter participant sometimes resorts to "because ... physics" simply because the former does not understand the physics.

Koyote

Side note, but this is one of the reasons why I left the P&R subforum, where my area of expertise often pops up. I would feel compelled to rebut nonsense, but it was almost always futile. When people's understanding of a subject is so low that they are embracing mythology, it's difficult to engage them with logic and evidence.

tomato coupe

Not only difficult, but generally not worth the time and effort required, because they will never consider that they are wrong.

PeteHski

How arrogant do you have to be to put your own subjective belief ahead of those guys at Swiss Side, Zipp, Best Bike Splits etc and people here with Physics, Maths and Engineering degrees? Maybe you could just argue that Newton’s second law is incomplete?

terrymorse 

As a racing tactic, it's quite realistic.

The climber with high power to bike+rider weight ratio attacks on the steepest section of the course, because it is where they:

• have the biggest advantage
• can inflict the most suffering on other riders
• stand the best chance of getting the biggest gap

The climber, once off the front, no longer has the advantage on the shallower grades. But if they have a substantial gap, the other riders may decide not to chase.

A racer picks the weapon that inflicts the most damage on their competitors. For a course with significant steep sections, a climber's most effective weapon is often reduced weight.

tomato coupe

Yeah, that's basic racing tactics. But, the effect of slightly less rotating mass in the attacker's wheels, which is the topic being debated, is meaningless.

PeteHski

I have exactly the same issue here and even more so on car forums. Having a background in engineering and vehicle dynamics can be pretty frustrating at times. But when I read something that is clear nonsense I can’t help but comment for the sake of anyone else who might actually believe it. Then you get told you are rude for even questioning the nonsense. There are a lot of armchair engineers around here that simply don’t want to listen.

PeteHski

Sure, if you can save a kg in weight then you may gain the best part of a minute on a 1 hour alpine climb for the same power. But the effect of reduced rotational inertia for your 30 sec attack (where you are probably accelerating for a handful of seconds at most) is going to be ridiculously small.

terrymorse 

Then there's the not well understood muscle fatigue effect of acceleration-deceleration on every pedal stroke. It's the "throwing a heavy ball a short distance vs. throwing a light ball a long distance" problem. It's certainly a small effect, given the wheel mass differences in question. But I'm not convinced (yet) it's ridiculously small.

elcruxio

Isn't weight inconsequential in that? You spend the same energy with a heavy and light bike but you just go slower with the heavier bike.

Also since the heavier wheel maintains speed better it'd likely be less fatiguing.