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 Post subject: Check this out!!!
PostPosted: Sat Aug 18, 2012 3:40 pm 
Retro Guru
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Shows up the likes of Shimano etc. who can't seem to think of anything new except more gears.

http://www.youtube.com/watch?v=toym0NTle5Q


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 Post subject:
PostPosted: Sat Aug 18, 2012 4:37 pm 
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Nice idea, but I'm afraid weight will still be an issue for anyone who isn't into downhill.


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 Post subject:
PostPosted: Sat Aug 18, 2012 4:59 pm 
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Raging_Bulls wrote:
Nice idea, but I'm afraid weight will still be an issue for anyone who isn't into downhill.


Only 14g heavier than xtr chainset with front derailer, can't see weight being an issue.


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 Post subject:
PostPosted: Sat Aug 18, 2012 8:08 pm 
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he'll be back.

anyways, i don't quite get it - fit chin ring with cut outs to help move chain onto smalller ring? seems like a solution to a problem that doesn't exist (at least for me)

what I was hoping to see was the segments being movable in and out so in effect increasing the number of teeth on the chain ring.


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PostPosted: Sat Aug 18, 2012 8:42 pm 
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02gf74 wrote:
what I was hoping to see was the segments being movable in and out so in effect increasing the number of teeth on the chain ring.


That is what happens. The segments move in above the small chainring one at a time picking the chain up as they go. Once they have all moved in the chain runs on the segements which make up the bigger chainring. Both chainrings when in use are in the same position so the chainline at the front is always the same. You can use the whole cassette in either chainring without crossing the chain anymore than you would normally in the middle ring. Also no rubbing front mech and you can shift under full load. I like it.


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 Post subject:
PostPosted: Sat Aug 18, 2012 8:56 pm 
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What he means is making the front chainring variable in size, so it can be the equivalent of a 32T, 33T, 34T, 52T, etc depending on the position of the front shifter.

Theoretically it's possible if you work with a lot of small segments that all expand outward. The key then is to keep the chainring as round as possible to avoid an exaggerated "Biopace-effect"


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 Post subject:
PostPosted: Sat Aug 18, 2012 9:27 pm 
retrobike rider
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Raging_Bulls wrote:
What he means is making the front chainring variable in size, so it can be the equivalent of a 32T, 33T, 34T, 52T, etc depending on the position of the front shifter.

Theoretically it's possible if you work with a lot of small segments that all expand outward. The key then is to keep the chainring as round as possible to avoid an exaggerated "Biopace-effect"


That would be hard to do as you are using a chain so have discrete steps. 'expanding' means it's not discrete steps (or digital as they like to all it).

A belt would probably be able to do it, but only if a toothed belt where not used.

Only possible solution is to have the teeth suddenly pop to their desired radius as soon as it leave the chain and at some point insert the missing tooth, sounds a bit complicated and unfeasible to me.


What is shown here is basically the Browning system take a step further.
I think it's rather neat.


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PostPosted: Sat Aug 18, 2012 11:18 pm 
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^^^ yes - i meant the chain ring would effectively increase in diameter - the segments would need to move so that they position themselves in increments of half a tooth tooth (so the difference is one whole tooth when adjecent segments have moved out) else the chain won't mesh - easier said than done .... which is why it hasn't been done.


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 Post subject:
PostPosted: Sun Aug 19, 2012 12:46 am 
Gold Trader / rb Rider / Special
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But if the correct ones came out you could essentially have '3 rings' as long as they were mounted correctly (not biopace orientation as you mentioned) but more like egg rings.
That said i think making the radii of the bigger and smaller rings would be a problem to get them to mate as one single ring and also as 2 seperate rings unless maybe the ends of all segments that would mate would be contoured inward for one and outward for the next piece to keep a round profile and mate them at the same time.


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