wagner@uw-june (Dave Wagner) (08/12/85)
Allow me to share with you my experience with the Huret Duopar:
I have just returned from a 3 week, 1100 mile bike tour (Washington/
British Columbia/Banff-Jasper). Before the tour, I decided the ol'
Shimano Crane GS (anybody else remember those?) was getting a little
sloppy, so I decided to purchase the whizziest derailleur around,
the Duopar. The Duopar is unique in that it utilizes two pantograph
mechanisms, one to move the derailleur body in and out (normal) and
the second to move the cage up and down (unusual).
Well, I was really impressed. The thing shifted practically at the speed
of thought! I was so used to overshifting with the old derailleur that
I was skipping around all over the freewheel until I got used to it!
So I'm out in the middle of nowhere, right, and suddenly I discover that
the Duopar's cage is getting mangled because the chain keeps slipping in
between the jockey (upper) pulley and the inside cage plate. You see, Huret
made a fatal design error in the Duopar: the inside (closer to the spokes)
cage plate is NOT attached to the jockey wheel axle; it is attached to
the tension wheel axle and to a small pin just below the jockey wheel.
The result is that the cage plate gets bent and the chain keeps slipping
in there. With bar-end shifters, as I'm sure anyone who owns
them is aware, it's pretty common to have your thigh hit the shift levers
when you dismount/mount the bike; this results in a slackening of the
cables and the rear derailleur trying to move out; which results in the
chain slipping into the aformentioned sore spot on the Duopar just about
every time you get back on the bike!!!! The problem is exacerbated by
the aforementioned cage pantograph mechanism: you wouldn't believe the
way this thing can twist itself up! The really bad stuff happens when you
are rolling the bike backwards, as you commonly do when trying to position
a loaded bike against a wall or signpost; the derailleur absolutely
gets mangled if you don't watch what you're doing.
Anyway, as the tour went on I found myself constantly bending and
re-bending the cage every time it would mangle itself.
Near the end of the tour I was seriously wondering if I would even
be able to finish! I couldn't use certain granny gears because
the derailleur was no longer willing to take up the chain slack,
and in other gears the jockey pulley was grinding against the cogs!
And on the second-to-last day of the tour, I had a mangle that was so
bad that it twisted one of the chain links - and I wasn't carrying
a chain riveting tool!!!! (I bent the link back using a couple of
vice grips!)
***************** THE IMPORTANT LESSON STARTS HERE *******************
Pretty soon I remembered what it was that I liked about the Shimano
derailleur: it's nearly indestructible. Shimano makes the only long
cage derailleurs that I know of that have both cage plates attached
to both pulley axles. The result is a very strong cage. Suntour
cages, as you probably well know, are open on one side to allow easy
chain removal from the cage. (The derailleur I had before the Shimano
was a Suntour Cyclone, whose cage also bent.) This is even true of
their so-called mountain bike derailleurs, which is really ludicrous
if you stop to think about it! On a mountain bike component, strength
and reliability should be the numero uno consideration, and things like
saving a few grams of cage weight (!) or even convenience of chain
removal should not even be a close second. I think that from now on I
will stick to Shimano rear derailleurs.
Anyway, when I got home the first thing I did is throw away that piece
of junk and put my old Shimano Crane back on. And you know what? It
still shifts beautifully!
I'd be interested to hear other people's experiences with touring
derailleurs.
Dave Wagner
University of Washington Comp Sci Department
wagner@washington.arpa
{ihnp4,decvax,ucbvax}!uw-beaver!uw-wally!wagner
"The surest thing there is is we are riders,
And though none too successful at it, guiders,
Through everything presented, land and tide
And now the very air, of what we ride."
- Frostbarrys@tekecs.UUCP (Barry Steel) (08/14/85)
As I sit looking at my Huret Duopar, I wonder after 3000+ miles why you had so many problems? I have done all of the same abuses that you have with no ill effect. I'm confused, it sounds like we are talking about two different animals (although the description is identical to mine). barry steel
shauns@vice.UUCP (Shaun Simpkins) (08/14/85)
> Allow me to share with you my experience with the Huret Duopar: > > << terrible experience related >> > > I'd be interested to hear other people's experiences with touring > derailleurs. > > Dave Wagner Well, I somewhat disagree with your evaluation of the Duropar, since I've ridden with one for the last year on a Trek 620 and have NEVER had chain mangles, reversing problems, slack takeup problems, or anything else for that matter since I got the bike - and I've been on several tours. Nothing like 1100 miles, but hevay touring in the Canadian Rockies plus lots of hilly local touring. I do agree with you that the Duropar is a very flexible derailleur; this shows up in some shifting vagueness. I think you've double trouble with barcon shifters and a flexible derailleur. Barcons make for sloppy shifting anyway. With the Duropar you want to be sure that the control linkage is very crisp. I have down tube shifters and like them a lot better than barcons - they never get bumped unexpectedly, and there's no shifting mush. I do notice now that after a year the shifting is a little sloppy, but this could be due to a whole bunch of problems - chain stretch, to name one. I may try the Sedis Traveler chain to make the shifting as crisp as I can. A derailleur that I haven't tried but that looks interesting is the Shimano Super Plate, a double pivot/movable jockey pulley design intended to equal or exceed the Duropar's performance. Bicycling magazine verified Shimano's claims, finding it stiffer than the Duropar as well. It certainly looks less fragile than its French competitor. If you're into very wide gear ranges and bulletproof shifting this may be a possibility. Anyone out there had any experience with the Super Plate? Until something really terrible happens, I still think the Duropar is an excellent, reliable design - but I'm openminded. The wandering squash, -- Shaun Simpkins uucp: {ucbvax,decvax,chico,pur-ee,cbosg,ihnss}!teklabs!tekcad!vice!shauns CSnet: shauns@tek ARPAnet:shauns.tek@rand-relay
kimr@azure.UUCP (Kim Rochat) (08/16/85)
> A derailleur that I haven't tried but that looks interesting is the > Shimano Super Plate, a double pivot/movable jockey pulley design intended > to equal or exceed the Duropar's performance. (...) > If you're into very wide gear ranges and bulletproof shifting this may be a > possibility. Anyone out there had any experience with the Super Plate? > When I ordered my tandem, I requested a Duopar rear derailleur. The builder refused, claiming that the Shimano Super Plate was much more durable. The bike was actually delivered with a SunTour LeTech since he hadn't gotten in a Superplate. I used it for 3 months, and had trouble with it shifting either too far or not far enough at both extremes. Repeated adjustments didn't help. The tandem has barcons, which do indeed make shifting somewhat vague, but you don't really want to take your hands off the handlebars on a tandem :-). Anyway, the builder exchanged the LeTech for a Superplate, which I find to shift much more positively, particularly under load. The gearing is 24/44/48 front, 11-32 rear. Kim Rochat tektronix!azure!kimr
peters@cubsvax.UUCP (Peter S. Shenkin) (08/22/85)
In article <> wagner@uw-june.UUCP writes: > ...You see, Huret >made a fatal design error in the Duopar: the inside (closer to the spokes) >cage plate is NOT attached to the jockey wheel axle... > >Anyway, as the tour went on I found myself constantly bending and >re-bending the cage every time it would mangle itself.... > >***************** THE IMPORTANT LESSON STARTS HERE ******************* > >Pretty soon I remembered what it was that I liked about the Shimano >derailleur: it's nearly indestructible. Shimano makes the only long >cage derailleurs that I know of that have both cage plates attached >to both pulley axles. The result is a very strong cage. Suntour >cages, as you probably well know, are open on one side to allow easy >chain removal from the cage. (The derailleur I had before the Shimano >was a Suntour Cyclone, whose cage also bent.) This is even true of >their so-called mountain bike derailleurs... > >I'd be interested to hear other people's experiences with touring >derailleurs. > REPLY STARTS HERE! I just got back from a 9-day, 400 mile tour of Yosemite -- heavily loaded bikes, lots of hills, etc. My bike has a Suntour XC rear derailleur, and contrary to the above assertion, it DOES have solid cage plates attached to the pulley axles. It behaved reliably throughout the trip. The design is simplicity itself, and is eminently field-servicible, though I didn't have to do any service. Like similar simple designs, you have to be prepared to overshift and correct a bit. My shifters are on the down tube, so it's not a problem for me; I don't know how the overshift characteristics compare with the Shimano Crane. I believe the XC is "above" the Mountech in the Suntour line (Mountech Doesn't have solid cage plates), since the next bike "down the line" from mine has Mountech. (I have a Univega Gran Tourissimo.) There were seven of us on the trip. One of us, Brian, had a Suntour LeTech, a movable jockey-pulley design. His last one only lasted a year, and he carried a spare. Any attempt to dissassemble it results in tiny parts flying out in all directions. According to him, the most common cause of failure is that the spring holding the jockey pulley wears out. Says it shifts beautifully under load, so he loves it. Peter S. Shenkin philabs!cubsvax!peters Columbia Univ. Biol. Sciences
kehoe@reed.UUCP (Dave Kehoe) (08/24/85)
I munched the first Duopar I ever installed when I worked at a bike shop. My boss wasn't pleased. You *must* shorten your chain by two or three pairs of links. The rule of thumb that chain length is correct when the derailleur pulleys are verticals in 1st and highest gears doesn't apply to Duopars. I've been happy with every derailleur I've owned (well, semi-happy back when I used Simplex Prestige's). I currently like the Shimano DuraAce best, but then I use a 13-21 freewheel (with 28-36 chainrings). I like the new Everest "Ultra-6" chain *much* better than the SedisSport -- shifting is 200% better. -- He still remembered hearing Andy Warhol say, "No, the best was when this guy bit off this guy's nose. That was the best sex." And William Burrough's answer: "I heard about that." -- "Wasn't that the best sex, Bill?" -- "Ah, yes, I imagine so." -- "The best." Dave Kehoe tektronix!reed!kehoe (503) 230-9454
sjc@angband.UUCP (Steve Correll) (08/26/85)
> My bike has a Suntour XC rear derailleur, and contrary to the [assertion > in an earlier posting], it DOES have solid cage plates attached to the > pulley axles... > > ...Mountech Doesn't have solid cage plates), I bought a Mountech recently which does have solid cage plates, even though the installation instructions packed with it boast about the cage being open on one side to allow you to remove the chain without disassembly (I ignored the instructions and unscrewed the jockey pulley to put the chain on). The Japanese manufacturers seem able to change their designs faster than their marketing people can assign new names and numbers to them. -- --Steve Correll sjc@s1-b.ARPA, ...!decvax!decwrl!mordor!sjc, or ...!ucbvax!dual!mordor!sjc