Non-linear efficiency loss in Planetary gears systems - was Re: [CR]Sheldon/Sturmey/etcetera


From: "jtaylor" <jtaylor@hfx.andara.com>
To: <classicrendezvous@bikelist.org>
References: <000a01c10998$1cdfea00$92b856d1@Marta>
Subject: Non-linear efficiency loss in Planetary gears systems - was Re: [CR]Sheldon/Sturmey/etcetera
Date: Wed, 11 Jul 2001 12:43:54 -0300


>----- Original Message -----
>From: "garth libre" <rabbitman@mindspring.com>
>To: <classicrendezvous@bikelist.org>
>Sent: July 10, 2001 8:29 PM
>Subject: [CR]Sheldon Brown and his planetary love of Sturmey Archer
>
>Really, my question is why not an internal 10 speed, instead of just 3,4 or 5? With carefull engineering, and >evolution of design wouldn't it be at least possible? I mean if we currently fit 10 cogs where we once had 5,
>then by slenderizing everything it should work. Why not? Garth in Surfside Libre
>

Derailleur gear systems have a relatively constant efficiency relative to number-of-gears, as each is a single stage. Planetary systems have only three possible ratios, so numbers-of-gears greater than that have multiple stages of gear-train, and multiple losses.

But then, sometimes I tell small children there are little mice in there doing all the work.