Re: group poll; cogsets

On Mon, 30 Jan 2006 17:10:01 -0800, jonisaacs wrote:

> Thoughts and comments:
>
>>>Mine overlap only on the wide-reach gears (big-big and little-little) that you
> shouldn't use anyway. I currently have a 46/30 and a 12-23 9-speed,
> and
> have 15 closely-spaced gears from 100" to 34", all jumps of less than
> 9%.
> ----------------
>
> Big-big and little-little are problems when using wide cog sets but
> with a 5 or 6 speed, those cross-overs are acceptable.

I could not use the 42/14 back in the days of 5-speed freewheels. The
chain rubbed on the inside of the big ring. Of course, those chains were
fatter, and less flexible. I don't recall whether or not they lasted
longer. Also, they were not much cheaper than you can find now, at least
on sale.

> My
> calculations suggest that there are only 14 different useable gear
> ratios with your setup.

No. 46 with the 12 through 19, then 30 with the 13 through 23. To be
honest, though, one of those jumps is actually a bit over 10%.

> Narrower chain => narrow bearings => faster wear. In any event, 7/8
> speed chains cost less.
>
> 3x5 or 3x6 can provide a wide range of useful cogs with some
> surprisingly close ratios.

At the cost of going to a triple, which is going to be more finicky about
shifting than a double.

--

David L. Johnson

__o | "Business!" cried the Ghost. "Mankind was my business. The
_`\(,_ | common welfare was my business; charity, mercy, forbearance,
(_)/ (_) | and benevolence, were, all, my business. The dealings of my
trade were but a drop of water in the comprehensive ocean of my
business!" --Dickens, "A Christmas Carol"
.

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