5 ms·

I haven't taken the time to compare the sizes of the effects, but it doesn't sit well that they blow past seemingly obvious ways extra wheel mass would go in th

I haven't taken the time to compare the sizes of the effects, but it doesn't sit well that they blow past seemingly obvious ways extra wheel mass would go in the opposite direction. I see at least two places they do this: Air Resistance: > However, this force will produce a greater change in speed on the bike with less mass. But the wheels act as (unsurprisingly) flywheels. Extra weight in the wheels adds both momentum and angular momentum, while frame mass adds only the former. This is exactly symmetric to their acceleration argument, so it's kind of shocking they skipped it. Internal Friction > More mass on a bike can increase the friction in the bearings—but again, this won’t matter where the mass is located. As an extreme example, a massful wheel with a massless frame clearly has no bearing friction. I'm pretty sure wheel weight does not contribute to bearing friction. Does anyone have any insight into why these matter less than the acceleration bit?

davidw 10y ago
In a road race, you have to attack to get away from the group, or win the race in a sprint. Either way, acceleration is critical.
- thedufer 10y ago
  That seems like a very reasonable observation, and I would accept that as an answer if this were a discussion about road racing. However, the completely unqualified title (including the word "prove") implies something deeper. Road racing is never mentioned.
  - mikekchar 10y ago
    It's very common for bicycle enthusiasts to equate "better" with road racing. It's not just acceleration away from the group either. Almost all the effort you put into cycling at high speeds (say over 30 km/h) is overcoming wind resistance. You can save a huge portion of that effort by drafting behind someone. So in terms of saving effort (or making other people hurt) making and closing gaps is crucial. But of course most people riding a bike are not racing. Even still acceleration is quite important. When you are on a relatively uniform gradient you can judge your power easily and make sure you don't go anaerobic. It's when you have to push hard to get over a small bump, or sprint ahead to get out of traffic, etc that you get into the red zone. Making those situations easier will make your whole ride easier. But it is fair to point out that "good" bikes are really only "better" for certain situations. For example, my wife almost never travels faster than 20 km/h. Many of the things that are absolutely necessary on a "good" bike that is travelling at 40+ km/h make absolutely no difference for her. Lot's of people tootle around at 10-15 km/h. Any well maintained bicycle will be completely fine. In fact a "good" bicycle will be unsatisfactory because it will be hard to handle. It's all about context. And in the context of talking about which bicycle is "better", the convention is to assume you are talking about road racing unless otherwise stated.
    - Thlom 10y ago
      Yes. For most people a good bike is a well maintained, comfortable bike with racks, fenders, chain guard and so on. For someone training for a triathlon a good bike is light, aggressive, a trillion gears etc.
    - eru 10y ago
      If you are not racing (and thus not subject to racing conditions) and you want to go fast, you should be riding a fully covered recumbent. There's only so much that toying around with slightly better uprights can do.
      - mikekchar 10y ago
        I have never ridden one (and I really want to ;-) ), but I've heard mixed reports on hills. You can push against the back of the seat, but you lose the advantage of using your weight on the pedals. Can anyone comment on what it's like for difficult hills? I have lots of gradients over 20% here and one of the hills I ride has a 30% section!
        BenFrantzDale 10y ago
        I have never ridden one either but weight on the pedals shouldn't matter. If you push down on a pedal as you extend your leg leaving your body at a constant height, that should be the same work as pushing just as hard over just as far against a seat. I'm sure there are subtleties – you can push more than your weight against a seat but a seat absorbs energy – but to first order it should be a wash.
        davidw 10y ago
        I'm skeptical. When you're up out of the pedals and sprinting on a bike, you are transmitting an awful lot of energy. I don't quite see being able to push quite so hard when sat down.
        BenFrantzDale 10y ago
ianpurton 10y ago
Hills and any time you need to accelerate.
- thedufer 10y ago
  I think hills are well covered - if you have to move the same amount of mass up either way, it doesn't much matter where said mass is on the bike. Accelerating, as the article mentions, is the one place that their theory holds. My question was why that's considered more important than holding speed (which heavier wheels makes easier) or the extra bearing friction.

davidw 10y ago

In a road race, you have to attack to get away from the group, or win the race in a sprint. Either way, acceleration is critical.

thedufer 10y ago
That seems like a very reasonable observation, and I would accept that as an answer if this were a discussion about road racing. However, the completely unqualified title (including the word "prove") implies something deeper. Road racing is never mentioned.
- mikekchar 10y ago
  It's very common for bicycle enthusiasts to equate "better" with road racing. It's not just acceleration away from the group either. Almost all the effort you put into cycling at high speeds (say over 30 km/h) is overcoming wind resistance. You can save a huge portion of that effort by drafting behind someone. So in terms of saving effort (or making other people hurt) making and closing gaps is crucial. But of course most people riding a bike are not racing. Even still acceleration is quite important. When you are on a relatively uniform gradient you can judge your power easily and make sure you don't go anaerobic. It's when you have to push hard to get over a small bump, or sprint ahead to get out of traffic, etc that you get into the red zone. Making those situations easier will make your whole ride easier. But it is fair to point out that "good" bikes are really only "better" for certain situations. For example, my wife almost never travels faster than 20 km/h. Many of the things that are absolutely necessary on a "good" bike that is travelling at 40+ km/h make absolutely no difference for her. Lot's of people tootle around at 10-15 km/h. Any well maintained bicycle will be completely fine. In fact a "good" bicycle will be unsatisfactory because it will be hard to handle. It's all about context. And in the context of talking about which bicycle is "better", the convention is to assume you are talking about road racing unless otherwise stated.
  - Thlom 10y ago
    Yes. For most people a good bike is a well maintained, comfortable bike with racks, fenders, chain guard and so on. For someone training for a triathlon a good bike is light, aggressive, a trillion gears etc.
  - eru 10y ago
    If you are not racing (and thus not subject to racing conditions) and you want to go fast, you should be riding a fully covered recumbent. There's only so much that toying around with slightly better uprights can do.
    - mikekchar 10y ago
      I have never ridden one (and I really want to ;-) ), but I've heard mixed reports on hills. You can push against the back of the seat, but you lose the advantage of using your weight on the pedals. Can anyone comment on what it's like for difficult hills? I have lots of gradients over 20% here and one of the hills I ride has a 30% section!
      - BenFrantzDale 10y ago
        I have never ridden one either but weight on the pedals shouldn't matter. If you push down on a pedal as you extend your leg leaving your body at a constant height, that should be the same work as pushing just as hard over just as far against a seat. I'm sure there are subtleties – you can push more than your weight against a seat but a seat absorbs energy – but to first order it should be a wash.
        davidw 10y ago
        I'm skeptical. When you're up out of the pedals and sprinting on a bike, you are transmitting an awful lot of energy. I don't quite see being able to push quite so hard when sat down.
        BenFrantzDale 10y ago

ianpurton 10y ago

Hills and any time you need to accelerate.

thedufer 10y ago
I think hills are well covered - if you have to move the same amount of mass up either way, it doesn't much matter where said mass is on the bike. Accelerating, as the article mentions, is the one place that their theory holds. My question was why that's considered more important than holding speed (which heavier wheels makes easier) or the extra bearing friction.