>I recently picked up a used Huret Duopar Eco
>model derailleur. Very interesting design!
>According to the archives it wasnt exactly the
>most robust derailleur ever made. Rolling a
>bike backwards could cause it to self destruct!
>That could definitely be a problem with a
>tandem. The derailleur did go through a number
>of small refinements over the years. This
>Japanese Huret page shows four Duopars about
>midway down the page...
>
>http://homepage3.nifty.com/passhunter/hunter/huret/huret.htm
>
>If you look at the last one it is a late
>Sachs/Huret labeled version and the arm
>connecting to the upper pulley has been beefed
>up quite a bit...
>
>http://homepage3.nifty.com/passhunter/hunter/huret/rdd4.htm
>
>Did these late models prove to be any stronger? Thanks for any feedback.
>
>Jim Cole
>Memphis, TN
I have used unmodified Duopars for years, on my camping (loaded touring) bike, on a tandem and on my city bike. Never had a problem with reliability, but then, I don't tend to pedal backwards violently. Never saw any use for that.
The biggest problem with the Duopar is that as an "early-shifting" derailleur, it will jump out of gear under hard acceleration as the bike flexes, especially if it isn't super-perfectly adjusted. See also the article "Riding with Classic Derailleurs, Part 1" in Bicycle Quarterly Vol. 4, No. 2.
This never is a problem on the camping bike on overland trips, but could be very annoying on the tandem, and even more so on the city bike when pulling a trailer and starting from a light.
Jan Heine
Editor
Bicycle Quarterly
140 Lakeside Ave #C
Seattle WA 98122
http://www.bikequarterly.com