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Not sure on the rules, but the women get to use carbon frames and rear disc wheels. Not sure about the other components (front wheel, pedals, bars, etc...)
Gros: https://i.imgur.com/KQnkh4B.jpg https://www.instagram.com/p/Bh8IpoeH...=gros_mathilde |
Originally Posted by carleton
(Post 20303317)
The International Girl's Keirin crew:
Anyone got a clue how we can view some of the men's or women's races? I just can't figure out the schedule. Stupid foreigners... |
Originally Posted by Baby Puke
(Post 20303415)
I would love to know this too. They come up randomly in my FB feed, but I still do not know how to plan to watch any particular keirin race, though presumably they are all there on keirin.jp
I just can't figure out the schedule. Stupid foreigners... (FYI: We are kidding. Baby Puke lives in Japan and races Keirin.) |
Actually I do kinda wish their website was a bit more foreign friendly- I mean just think of all the track nerds the world over that would be all over that! And you can bet live on there too, apparently!
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Originally Posted by carleton
(Post 20294732)
Saw this post by Joe Truman. The JKA riders are required to pass an exam where they are tested on (I think) disassembling and reassembling their bikes. Maybe @Baby Puke can expound on this.
https://www.instagram.com/p/Bhtc1HEh...-by=joetruman1 Also, JKA riders are required to buy their own frames. Nice. |
Originally Posted by carleton
(Post 20303323)
Not sure on the rules, but the women get to use carbon frames and rear disc wheels. Not sure about the other components (front wheel, pedals, bars, etc...)
|
Originally Posted by Baby Puke
(Post 20303415)
I just can't figure out the schedule. Stupid gaijin... |
Originally Posted by taras0000
(Post 20303771)
Fixed that for you. Lol.
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Apparently this is the 9t cog setup Bos has been using:
https://www.instagram.com/p/Bh-pPQll...mekaanikko9239 |
Originally Posted by seau grateau
(Post 20305665)
Apparently this is the 9t cog setup Bos has been using:
https://www.instagram.com/p/Bh-pPQll...mekaanikko9239 |
Originally Posted by seau grateau
(Post 20305665)
Apparently this is the 9t cog setup Bos has been using:
https://www.instagram.com/p/Bh-pPQll...mekaanikko9239 That appears to be the IG of the guy who made it. |
Originally Posted by carleton
(Post 20305684)
Great find!
That appears to be the IG of the guy who made it. https://www.facebook.com/mekaanikko9239/ https://scontent-lax3-1.xx.fbcdn.net...db&oe=5B613C75 |
That dude is about to be reeeeealy popular.
OK, kiiiiinda popular. I'm sure there are plenty of trackies that would pay to have one looking for that "edge". I don't think it will unlock some hidden power or whatever. But, having a 9 or 10t cog-ed wheel is an interesting training tool for functional muscle development on the track. That being said, a spin bike or home trainer would do the same thing, but at home. I would buy one. Basically to do slow-motion standing starts to work on technique. |
These are for sale at at least one shop that I know of here.
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Originally Posted by carleton
(Post 20303317)
The International Girl's Keirin crew:
Anyone got a clue how we can view some of the men's or women's races? |
Originally Posted by southernfox
(Post 20305790)
Ooof. Do they call the men's "Boy's"? ...pet peeve of mine.
On the plus side, it's great that the women get to compete and also earn a pretty great living from being track sprinters. |
The JCF, and Keirin even more so, are stuck in the 1950s. It's bizarre to see Women's Keirin being promoted by a moribund federation -- but anything to combat declining gambling revenues I guess.
|
Originally Posted by southernfox
(Post 20305790)
Ooof. Do they call the men's "Boy's"? ...pet peeve of mine.
1950's indeed. |
Originally Posted by Baby Puke
(Post 20305859)
It's super annoying and sexist. Japan is in the 1950's in a lot of ways, unfortunately. Please don't look at their (totally pink and "girly") uniforms...
On the plus side, it's great that the women get to compete and also earn a pretty great living from being track sprinters. |
Originally Posted by taras0000
(Post 20305679)
Tha cannot be efficient. ...............................
As the number of sprocket teeth decreases the chain link at the top of the cog carries more of the chain load and following links take less of the chain load. This results in deformation of chain components and increased bearing stress on the sprocket teeth; the result is more friction and decreased efficiency. There is an interesting article on the effects of bicycle chain efficiency here: http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf Figure 2 shows measured drive chain efficiency for 21, 15, and 11 tooth cogs. My guess is that a 9 tooth cog would yield a transmission efficiency of 91% or less. The hub shown in post 1939 is a special design; there are several hex headed bolts holding the hub body together. To change cog size requires partial disassembly of the hub. |
Originally Posted by 700wheel
(Post 20306586)
I agree.
As the number of sprocket teeth decreases the chain link at the top of the cog carries more of the chain load and following links take less of the chain load. This results in deformation of chain components and increased bearing stress on the sprocket teeth; the result is more friction and decreased efficiency. There is an interesting article on the effects of bicycle chain efficiency here: http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf Figure 2 shows measured drive chain efficiency for 21, 15, and 11 tooth cogs. My guess is that a 9 tooth cog would yield a transmission efficiency of 91% or less. The hub shown in post 1939 seems to be a special design; there are several hex headed bolts holding the hub body together. Surprised that the highest chain tension was the most efficient (but I don't know how high the tension was, 305N doesn't mean much to me, maybe there's a limit where it gets less efficient again, like we've all heard?). Bigger difference in the efficiency with smaller cogs than I thought there would be too. I knew they were less efficient, but I didn't know they were THAT much more less efficient. I'm curious if their results hold up at higher RPM and higher power, or if the loss in power isn't dependent on power and the actually efficiency would go up across the board at a more reasonable power (and RPM). 70 RPM and 175W isn't a scenario that occurs very often. |
Originally Posted by spartanKid
(Post 20307276)
I wonder how applicable are these chain tensions measurements to track/fixed gear bikes. Their testing setup as a rear derailleur.
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https://i.imgur.com/h6PN89u.jpg
From: https://www.instagram.com/p/BiESPd6h...aurinevriessen Non-NJS stuff I see: - Carbon frames from those that make steel NJS frames - SRM - modern Shimano Dura Ace pedals - G-Race pedal straps (I think) - Mavic Ellipse - Saddles of choice - Carbon handlebars (not sure what make/model) Not sure if this is training or race gear, though. Interesting nonetheless. |
Originally Posted by 700wheel
(Post 20306586)
I agree.
As the number of sprocket teeth decreases the chain link at the top of the cog carries more of the chain load and following links take less of the chain load. This results in deformation of chain components and increased bearing stress on the sprocket teeth; the result is more friction and decreased efficiency. There is an interesting article on the effects of bicycle chain efficiency here: http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf Figure 2 shows measured drive chain efficiency for 21, 15, and 11 tooth cogs. My guess is that a 9 tooth cog would yield a transmission efficiency of 91% or less. The hub shown in post 1939 is a special design; there are several hex headed bolts holding the hub body together. To change cog size requires partial disassembly of the hub. |
Originally Posted by seau grateau
(Post 20305665)
Apparently this is the 9t cog setup Bos has been using:
https://www.instagram.com/p/Bh-pPQll...mekaanikko9239 Slumworm: Game Changer : 9T Cogs & 14mm Axle Hubs |
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