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The immediate question is: if they are more efficient, why aren't all disciplines using these? The article doesn't say! It suggests in passing that Triathlon h

The immediate question is: if they are more efficient, why aren't all disciplines using these? The article doesn't say! It suggests in passing that Triathlon has different rules because it doesn't allow "drafting" (Which I'm guessing is something related to team-riding to reduce air resistance, but the article doesn't explain what it is). Are there any rules prescribing (say) that a tour de France bike must use a normal (double triangle) design? Or is that just used because a traditional frame is optimal for weight rather than aerodynamics?

strken 3y ago
The article explicitly says that UCI banned NDD bikes. Given that the Tour de France is a UCI event the answer seems obvious.
- alkonaut 3y ago
  The question I guess is: are UCI-governed events not using "NDD" bikes only because of regulations on what shape can be used, or is triathlon special in that it favors aerodynamics more than other events? That is: if regulation was dropped, would pro cycling be filled with weird looking CF monocoque designs, or is the traditional design still optimal for some use cases (e.g. for weight and events with team ridning and lots of climbing)?
  - hermitdev 3y ago
    UCI has strict regulations on the geometry, weight and even ancillary equipment (think brakes, gear shifts) of bikes. I vaguely recall the minimum weight being something like 14.9 lbs, but this is likely incorrect. Point is, it's quite possible to make a bike that is lighter than this while still remaining safe for racing. I've heard of some using lead ballast to make weight. One advantage of this, though, is you can choose where to place the weight, such as in the bottom of the frame, near the crank, lowering center of gravity and helping stability a bit. The regs do make for some funny situations though. Take a look at a pro peloton and look for the shortest rider, preferably someone close to 5 feet tall. Their bike will be comically oversized for them. The UCI tends to be a fairly conservative organization that favors tradition over accepting the latest technology and design trends, especially with road racing. You're more likely to see new technology in non road disciplines such as cyclocross or mountain biking. Just see disc brakes only just getting into road racing in the past several years (I've not been following racing closely anymore, so not sure when).
  - pmontra 3y ago
    If regulations were dropped they would race with egg shaped bicycles, because of aerodynamics. They are very fast. Google that term, lots of funny pictures. On climbs, I don't know how they perform. On descents, I have no idea about their safety. Even without going to those extremes, they need a tradeoff bike between going fast on level roads, climbing, descending, replacing flat tires, overall weight, etc. So something like those NDD bikes with maybe a switch to more extreme shapes on long flat courses.
  - prmoustache 3y ago
    > That is: if regulation was dropped, would pro cycling be filled with weird looking CF monocoque designs, or is the traditional design still optimal for some use cases (e.g. for weight and events with team ridning and lots of climbing)? The original Lotus bike mentionned above was introduced and used in olympic events. Chris Boardman held for a long time the speed record in a grand tour time trial that he set with the original road Lotus Bike (the track version he used at Barcelona olympics predates it): https://www.youtube.com/watch?v=OjJ60Kx2j8I https://www.youtube.com/watch?v=OjJ60Kx2j8I Also Miguel Indurain in the 90's used the "Espada" time trial pinarello bike and some of his rivals used also non diamond shaped carbon bikes.
  - mrgoldenbrown 3y ago
    Really depends on what regulations remain. If you drop too many regulations,you could end up with recumbent bikes with aero fairings.
kwkelly 3y ago
It does say the UCI banned NDD bikes in 1999.
TomK32 3y ago
Beside the UCI ruining everything for almost every cycling sport, you can't even do a superman these days, there's also the NJS in Japan who do the same for track cycling in Japan. Which is a massive sport and betting market. Btw, Graeme Obree is/was one of the most innovative cyclists, he came up with ideas the UCI didn't like at all. But he's such an outstanding personality and inspiration.
- giraffe_lady 3y ago
  I don't know anything about UCI but keirin is intentionally a very narrow and heavily restricted slice of sport cycling. I've never heard anyone who is into it have anything negative to say about NJS's equipment restrictions. It is like how even though riflery is a sport, archery still is too. The governing body of archery isn't doing something profane by restricting the technology of the sport, that restriction is the sport.
  - zh3 3y ago
    Agreed, Keirin (in my limited knowledge) aims to keep things pure in their particular area (making competition a level playing field). By comparison, the UCI wants to have control over a much wider part of cycling (and so want to rule over what innovations we can and can't have).
- scheme271 3y ago
  NJS is intentionally heavily prescriptive since people bet on the outcomes of the keirin races. The racers even announce what tactics they'll use during the race so that gamblers can decide who to bet on.
- zh3 3y ago
  +1 for Obree - more people should know the history. For those into cycling who don't already know them, the Obree book [0] and film [1] are worth the time. [0] https://www.goodreads.com/book/show/231993.Flying_Scotsman_ https://www.goodreads.com/book/show/231993.Flying_Scotsman_ [1] https://www.imdb.com/title/tt0472268/ https://www.imdb.com/title/tt0472268/
nordsieck 3y ago
> Or is that just used because a traditional frame is optimal for weight rather than aerodynamics? It's exactly this tradeoff. Time trial bikes are generally optimized for aerodynamic efficiency since there generally isn't a lot of climbing they do. Climbing bikes are generally optimized for weight - typically with more basic looking tubes. And for many sections, riders pick a hybrid bicycle with some aero features, but also with an emphasis on light weight.
jdietrich 3y ago
>Are there any rules prescribing (say) that a tour de France bike must use a normal (double triangle) design? Yes. The UCI is the international governing body for most forms of cycle sport. UCI regulation 1.3.020 states: For road, track and for cyclo-cross competitions, the frame of the bicycle shall be of a traditional pattern, i.e. built around a main triangle. A complex set of rules govern the permissible shape and construction of a bicycle used in UCI-sanctioned competition, similar to the rules governing Formula 1 or NASCAR. These rules are shaped by competing and often contrary aims of many stakeholders - to ensure safety, to maintain the traditional aesthetics of cycling, to allow fair competition for less well-funded nations and teams, to allow equipment manufacturers to showcase innovative new products etc. The design of a modern racing bicycle is guided as much by politics as engineering. https://assets.ctfassets.net/761l7gh5x5an/wQympSG6EWlKq6o6HKw9E/06476118f9497fcaaec76bf422475a80/1-GEN-20240101-E.pdf https://assets.ctfassets.net/761l7gh5x5an/wQympSG6EWlKq6o6HK... https://assets.ctfassets.net/761l7gh5x5an/7s1ma6mVAVlFwi8rRgy0Iw/50fda3854ab916cc8a7ff346233c2df9/Clarification_Guide_of_the_UCI_Technical_Regulation_-_20240110_-_ENG.pdf https://assets.ctfassets.net/761l7gh5x5an/7s1ma6mVAVlFwi8rRg...
rhinoceraptor 3y ago
The tucked aero position is only allowed in time trials since it's unsafe when riding in a pack, so UCI compliant time trials bikes look pretty similar to triathlon bikes, just with the traditional double diamond frame design.
l1tany11 3y ago
Basically there are a lot of reasons, but it all comes down to a small aerodynamic efficiency gain is no where near the sacrifice required in the other disciplines. in other cycling disciplines the efficiency of a rider on a flat smooth road, in the wind (no drafting) without significant corners or descents (no technicality) matters far less, and/or how you get efficiency is different. In fact in other disciplines that situation basically doesn’t exist. Keep in mind that for a lot of people, for a long time, the pinnacle of triathlon, and primarily how these bikes are marketed and designed, is around the Ironman World Championships in Kona. The 112 mile course only has 4500ft of elevation gain. That is very flat. Additionally some top triathlon pros consider even themselves to be basically beginner level bike handlers compared to road bikers. Which is basically beginner level bike handling compared to mountain biking. Why can you win races and compete for world championships if you have such poor skills? Because in that discipline courses are designed such that one needs virtually no skill, and the bikes are thus not designed at all for handling. Meanwhile in road bike racing, such as the Tour de France, riders can win races or stages due to their descending skills despite bike handling not being a top priority of the discipline (look at Tom Pidcocks performance vs Chris Froome on Alpe d’Huez in 2022). Also in road bike racing, protected riders are protected from the wind 99% of the time or more. It’s more important to be able to get close to the rider in front of you, and to still have control of your bike, than to be extremely aerodynamic yourself as most of those gains are lost in the draft. Especially true in the peloton, where riders frequently talk about the feeling of being “sucked along” and not having to pedal basically at all. It’s almost hard to believe, but it’s wild when you actually experience it. In mountain biking for instance, control, grip, flexibility of body position etc is much more important than just outright aerodynamic efficiency. Rolling resistance too is a much bigger proportion of the energy lost than on smooth roads. Speeds are also naturally slower due to the fact that courses are not only off road, but often much steeper than what is typically found on road. Additionally aerodynamics matter little if you can’t complete the course without crashing/blowing up your bike. (See Peter Sagan at the Olympics where he DNFd.)

strken 3y ago

The article explicitly says that UCI banned NDD bikes. Given that the Tour de France is a UCI event the answer seems obvious.

alkonaut 3y ago
The question I guess is: are UCI-governed events not using "NDD" bikes only because of regulations on what shape can be used, or is triathlon special in that it favors aerodynamics more than other events? That is: if regulation was dropped, would pro cycling be filled with weird looking CF monocoque designs, or is the traditional design still optimal for some use cases (e.g. for weight and events with team ridning and lots of climbing)?
- hermitdev 3y ago
  UCI has strict regulations on the geometry, weight and even ancillary equipment (think brakes, gear shifts) of bikes. I vaguely recall the minimum weight being something like 14.9 lbs, but this is likely incorrect. Point is, it's quite possible to make a bike that is lighter than this while still remaining safe for racing. I've heard of some using lead ballast to make weight. One advantage of this, though, is you can choose where to place the weight, such as in the bottom of the frame, near the crank, lowering center of gravity and helping stability a bit. The regs do make for some funny situations though. Take a look at a pro peloton and look for the shortest rider, preferably someone close to 5 feet tall. Their bike will be comically oversized for them. The UCI tends to be a fairly conservative organization that favors tradition over accepting the latest technology and design trends, especially with road racing. You're more likely to see new technology in non road disciplines such as cyclocross or mountain biking. Just see disc brakes only just getting into road racing in the past several years (I've not been following racing closely anymore, so not sure when).
- pmontra 3y ago
  If regulations were dropped they would race with egg shaped bicycles, because of aerodynamics. They are very fast. Google that term, lots of funny pictures. On climbs, I don't know how they perform. On descents, I have no idea about their safety. Even without going to those extremes, they need a tradeoff bike between going fast on level roads, climbing, descending, replacing flat tires, overall weight, etc. So something like those NDD bikes with maybe a switch to more extreme shapes on long flat courses.
- prmoustache 3y ago
  > That is: if regulation was dropped, would pro cycling be filled with weird looking CF monocoque designs, or is the traditional design still optimal for some use cases (e.g. for weight and events with team ridning and lots of climbing)? The original Lotus bike mentionned above was introduced and used in olympic events. Chris Boardman held for a long time the speed record in a grand tour time trial that he set with the original road Lotus Bike (the track version he used at Barcelona olympics predates it): https://www.youtube.com/watch?v=OjJ60Kx2j8I https://www.youtube.com/watch?v=OjJ60Kx2j8I Also Miguel Indurain in the 90's used the "Espada" time trial pinarello bike and some of his rivals used also non diamond shaped carbon bikes.
- mrgoldenbrown 3y ago
  Really depends on what regulations remain. If you drop too many regulations,you could end up with recumbent bikes with aero fairings.

kwkelly 3y ago

It does say the UCI banned NDD bikes in 1999.

TomK32 3y ago

Beside the UCI ruining everything for almost every cycling sport, you can't even do a superman these days, there's also the NJS in Japan who do the same for track cycling in Japan. Which is a massive sport and betting market. Btw, Graeme Obree is/was one of the most innovative cyclists, he came up with ideas the UCI didn't like at all. But he's such an outstanding personality and inspiration.

giraffe_lady 3y ago
I don't know anything about UCI but keirin is intentionally a very narrow and heavily restricted slice of sport cycling. I've never heard anyone who is into it have anything negative to say about NJS's equipment restrictions. It is like how even though riflery is a sport, archery still is too. The governing body of archery isn't doing something profane by restricting the technology of the sport, that restriction is the sport.
- zh3 3y ago
  Agreed, Keirin (in my limited knowledge) aims to keep things pure in their particular area (making competition a level playing field). By comparison, the UCI wants to have control over a much wider part of cycling (and so want to rule over what innovations we can and can't have).
scheme271 3y ago
NJS is intentionally heavily prescriptive since people bet on the outcomes of the keirin races. The racers even announce what tactics they'll use during the race so that gamblers can decide who to bet on.
zh3 3y ago
+1 for Obree - more people should know the history. For those into cycling who don't already know them, the Obree book [0] and film [1] are worth the time. [0] https://www.goodreads.com/book/show/231993.Flying_Scotsman_ https://www.goodreads.com/book/show/231993.Flying_Scotsman_ [1] https://www.imdb.com/title/tt0472268/ https://www.imdb.com/title/tt0472268/

nordsieck 3y ago

> Or is that just used because a traditional frame is optimal for weight rather than aerodynamics? It's exactly this tradeoff. Time trial bikes are generally optimized for aerodynamic efficiency since there generally isn't a lot of climbing they do. Climbing bikes are generally optimized for weight - typically with more basic looking tubes. And for many sections, riders pick a hybrid bicycle with some aero features, but also with an emphasis on light weight.

jdietrich 3y ago

>Are there any rules prescribing (say) that a tour de France bike must use a normal (double triangle) design? Yes. The UCI is the international governing body for most forms of cycle sport. UCI regulation 1.3.020 states: For road, track and for cyclo-cross competitions, the frame of the bicycle shall be of a traditional pattern, i.e. built around a main triangle. A complex set of rules govern the permissible shape and construction of a bicycle used in UCI-sanctioned competition, similar to the rules governing Formula 1 or NASCAR. These rules are shaped by competing and often contrary aims of many stakeholders - to ensure safety, to maintain the traditional aesthetics of cycling, to allow fair competition for less well-funded nations and teams, to allow equipment manufacturers to showcase innovative new products etc. The design of a modern racing bicycle is guided as much by politics as engineering. https://assets.ctfassets.net/761l7gh5x5an/wQympSG6EWlKq6o6HKw9E/06476118f9497fcaaec76bf422475a80/1-GEN-20240101-E.pdf https://assets.ctfassets.net/761l7gh5x5an/wQympSG6EWlKq6o6HK... https://assets.ctfassets.net/761l7gh5x5an/7s1ma6mVAVlFwi8rRgy0Iw/50fda3854ab916cc8a7ff346233c2df9/Clarification_Guide_of_the_UCI_Technical_Regulation_-_20240110_-_ENG.pdf https://assets.ctfassets.net/761l7gh5x5an/7s1ma6mVAVlFwi8rRg...

rhinoceraptor 3y ago

The tucked aero position is only allowed in time trials since it's unsafe when riding in a pack, so UCI compliant time trials bikes look pretty similar to triathlon bikes, just with the traditional double diamond frame design.

l1tany11 3y ago

Basically there are a lot of reasons, but it all comes down to a small aerodynamic efficiency gain is no where near the sacrifice required in the other disciplines. in other cycling disciplines the efficiency of a rider on a flat smooth road, in the wind (no drafting) without significant corners or descents (no technicality) matters far less, and/or how you get efficiency is different. In fact in other disciplines that situation basically doesn’t exist. Keep in mind that for a lot of people, for a long time, the pinnacle of triathlon, and primarily how these bikes are marketed and designed, is around the Ironman World Championships in Kona. The 112 mile course only has 4500ft of elevation gain. That is very flat. Additionally some top triathlon pros consider even themselves to be basically beginner level bike handlers compared to road bikers. Which is basically beginner level bike handling compared to mountain biking. Why can you win races and compete for world championships if you have such poor skills? Because in that discipline courses are designed such that one needs virtually no skill, and the bikes are thus not designed at all for handling. Meanwhile in road bike racing, such as the Tour de France, riders can win races or stages due to their descending skills despite bike handling not being a top priority of the discipline (look at Tom Pidcocks performance vs Chris Froome on Alpe d’Huez in 2022). Also in road bike racing, protected riders are protected from the wind 99% of the time or more. It’s more important to be able to get close to the rider in front of you, and to still have control of your bike, than to be extremely aerodynamic yourself as most of those gains are lost in the draft. Especially true in the peloton, where riders frequently talk about the feeling of being “sucked along” and not having to pedal basically at all. It’s almost hard to believe, but it’s wild when you actually experience it. In mountain biking for instance, control, grip, flexibility of body position etc is much more important than just outright aerodynamic efficiency. Rolling resistance too is a much bigger proportion of the energy lost than on smooth roads. Speeds are also naturally slower due to the fact that courses are not only off road, but often much steeper than what is typically found on road. Additionally aerodynamics matter little if you can’t complete the course without crashing/blowing up your bike. (See Peter Sagan at the Olympics where he DNFd.)