Dura Ace Slant Parallelogram?
#1
Bianchi Goddess
Thread Starter
Join Date: Apr 2009
Location: Shady Pines Retirement Fort Wayne, In
Posts: 27,858
Bikes: Too many to list here check my signature.
Mentioned: 192 Post(s)
Tagged: 2 Thread(s)
Quoted: 2930 Post(s)
Liked 2,926 Times
in
1,491 Posts
Dura Ace Slant Parallelogram?
When did Dura Ace steal the Slant Parallelogram design from Suntour? I think I missed out on a real deal for an early DA group but I want to have a slanted RD for the smoother shifting. This was on FB for only $200 depending on currency exchange
I looked over Velobase but I really can't tell when it acquires the slant design.
I was thinking this would look great, but kind of retro, on the "Speckled Trout" Bertoni
I looked over Velobase but I really can't tell when it acquires the slant design.
I was thinking this would look great, but kind of retro, on the "Speckled Trout" Bertoni
__________________
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
Likes For Bianchigirll:
#2
Senior Member
Join Date: Apr 2012
Location: Middle Earth (aka IA)
Posts: 20,435
Bikes: A bunch of old bikes and a few new ones
Mentioned: 178 Post(s)
Tagged: 0 Thread(s)
Quoted: 5888 Post(s)
Liked 3,471 Times
in
2,079 Posts
Likes For bikemig:
#3
Senior Member
Join Date: Jan 2019
Posts: 528
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 237 Post(s)
Likes: 0
Liked 83 Times
in
64 Posts
Shimano slant parallelograms started with SIS, so 7400. RD-7300 was the weird AX thing. RD-7200 is merely a dual sprung dropped parallelogram that was an evolution of the Crane.
Likes For Kuromori:
#4
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,786
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3588 Post(s)
Liked 3,400 Times
in
1,934 Posts
The derailleur in your picture is pre-slant parallelogram. As @bikemig notes above, SunTour's patent on the design only lapsed in 1984, and the first Shimano slant-parallelogram derailleur, the Dura-Ace 7400, came out late that year with the first SIS indexed drivetrain:
#5
Bianchi Goddess
Thread Starter
Join Date: Apr 2009
Location: Shady Pines Retirement Fort Wayne, In
Posts: 27,858
Bikes: Too many to list here check my signature.
Mentioned: 192 Post(s)
Tagged: 2 Thread(s)
Quoted: 2930 Post(s)
Liked 2,926 Times
in
1,491 Posts
OK Thanks. That was what I thought, but even the 7400 doesn't look that slanted. I think I'll just keep looking for a VGC Superbe or Sprint or 1st Gen Chorus that won't break the bank
__________________
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
#6
feros ferio
Join Date: Jul 2000
Location: www.ci.encinitas.ca.us
Posts: 21,798
Bikes: 1959 Capo Modell Campagnolo; 1960 Capo Sieger (2); 1962 Carlton Franco Suisse; 1970 Peugeot UO-8; 1982 Bianchi Campione d'Italia; 1988 Schwinn Project KOM-10;
Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 1393 Post(s)
Liked 1,326 Times
in
837 Posts
Once the SunTour patent expired, almost everyone copied the design as quickly as possible, because it makes so much sense.
__________________
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
#7
Bianchi Goddess
Thread Starter
Join Date: Apr 2009
Location: Shady Pines Retirement Fort Wayne, In
Posts: 27,858
Bikes: Too many to list here check my signature.
Mentioned: 192 Post(s)
Tagged: 2 Thread(s)
Quoted: 2930 Post(s)
Liked 2,926 Times
in
1,491 Posts
__________________
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
#8
tantum vehi
Join Date: Jul 2008
Location: Flathead Valley, MT
Posts: 4,440
Bikes: More than I care to admit
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 1167 Post(s)
Liked 992 Times
in
491 Posts
They did. You don’t just happen to have a fully functioning indexed rear derailleur that will soon become the standard for an entire industry in the same year that a patent expires without having done metric crap-ton of R&D first.
__________________
1970 Gitane TdF; 1973 Gitane TdF
1979 Trek 710; 1981 Trek 412; 1981 Trek 710
1984 Specialized Stumpjumper Sport; 1985 Specialized Allez SE; 1988 Specialized Sirrus; 1989 Specialized Rock Combo
1984 Ross Mt. Hood
1988 Centurion Ironman Expert
1991 Bridgestone RB-1
1992 Serotta Colorado TG
2015 Elephant NFE
1979 Trek 710; 1981 Trek 412; 1981 Trek 710
1984 Specialized Stumpjumper Sport; 1985 Specialized Allez SE; 1988 Specialized Sirrus; 1989 Specialized Rock Combo
1984 Ross Mt. Hood
1988 Centurion Ironman Expert
1991 Bridgestone RB-1
1992 Serotta Colorado TG
2015 Elephant NFE
Likes For mountaindave:
#9
ambulatory senior
Join Date: Dec 2016
Location: Peoria Il
Posts: 5,998
Bikes: Austro Daimler modified by Gugie! Raleigh Professional and lots of other bikes.
Mentioned: 76 Post(s)
Tagged: 0 Thread(s)
Quoted: 1955 Post(s)
Liked 3,661 Times
in
1,679 Posts
I've got one of the old 600s that is ok but definitly not smooth.
#10
Senior Member
Join Date: Dec 2015
Location: San Diego
Posts: 703
Bikes: 1978 Bruce Gordon, 1977 Lippy, 199? Lippy tandem, Bike Friday NWT, 1982 Trek 720, 2012 Rivendell Atlantis, 1983 Bianchi Specialissima?
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 345 Post(s)
Liked 175 Times
in
107 Posts
Interested in either? I also have a black Cyclone which I believe is first generation.
Likes For L134:
#11
Pedal to the medal
#12
Senior Member
Join Date: Jun 2006
Posts: 20,305
Mentioned: 130 Post(s)
Tagged: 0 Thread(s)
Quoted: 3464 Post(s)
Liked 2,829 Times
in
1,995 Posts
Shimano was keenly aware of the looming patent expiration. They had designed, tested and tooled up for the 7400 With SIS and were ready to deliver. Shimano was cunning, 6, 7, 8 cogs, then integrated brake/ shift, tipped the scales and got freehubs popular, which had been around since the EX series but resisted.
( note the planned obsolescence along the way- design stability was over )
Campagnolo by their patent applications was desperate to come up with a patentable alternative in the early 80’s. There was none, the closest that was employed was the extending diagonal rod in the Croce’ mech and the A, B variable geometry - I think used on Chorus.
they really struggled to avoid using the slant parallelogram- even after it was open source.
almost cost them the company.
eventually they got going. Dark days until they did. Must have been a terrible time there, they had been the developer of patents that gave them an edge- then were out developed. Not humble enough to accept outside concepts.
Likes For repechage:
#13
tantum vehi
Join Date: Jul 2008
Location: Flathead Valley, MT
Posts: 4,440
Bikes: More than I care to admit
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 1167 Post(s)
Liked 992 Times
in
491 Posts
FIFY
The graphic looked a lot like Campy Super Record (without the slant parallelogram) which in turn looked a lot like first gen Cyclone (the origin of the slant parallelogram). So the real winner here is clearly...
Photo from Disraeli Gears
The graphic looked a lot like Campy Super Record (without the slant parallelogram) which in turn looked a lot like first gen Cyclone (the origin of the slant parallelogram). So the real winner here is clearly...
Photo from Disraeli Gears
Last edited by mountaindave; 02-23-20 at 10:51 AM.
Likes For mountaindave:
#14
Senior Member
Join Date: Aug 2007
Location: Evanston, IL
Posts: 5,093
Bikes: many
Mentioned: 63 Post(s)
Tagged: 0 Thread(s)
Quoted: 1444 Post(s)
Liked 1,392 Times
in
760 Posts
I believe the only company that might have stolen the slant parallelogram was Rino. Everybody else waited until the patent ran out.
#15
Senior Member
Join Date: Jan 2019
Posts: 528
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 237 Post(s)
Likes: 0
Liked 83 Times
in
64 Posts
After SIS was introduced, it became about trying to make a working index system, which was either done by copying Shimano that copied the slant from Suntour, or trying to come up with alternative designs and failing as with many of Campagnolo's Syncro designs. I'm having a hard time thinking of any slant designs other than Suntour and Rino that were meant only for friction, and Rino was making Suntour knockoffs before the patent expired. You can really tell the slant parallelogram derailers are Shimano RD-7400 derived when they have a sprung B-pivot.
#16
Ride, Wrench, Swap, Race
Join Date: Jan 2010
Location: Northern California
Posts: 9,194
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
Mentioned: 132 Post(s)
Tagged: 0 Thread(s)
Quoted: 1565 Post(s)
Liked 1,296 Times
in
866 Posts
OP mentioned possible differing degree of slant. I have wondered about this, but find it hard to visually verify.
Campy did also have an Athena (and later Xenon) Synchro derailer with a slanted parallelogram, but with very little in the way of a drop-down knuckle (just merely an offset up top would be one way of looking at this). They apparently didn't want to appear "copycat", but soon relented as pressure mounted to achieve indexing perfection with the longer cables of integrated shifters. So this earlier slanted design never made it past when Ergolevers were fitted at these respective Athena and Xenon levels.
Slanted parallelograms have a problem though, which ultimately limits how much slant will still work with how much return-spring tension. Only a non-slanted parallelogram will eliminate any road impact vibration from trying to bounce the cage inward and outward (with only return-spring tension and the cable resisting this tendency). Note that traditional non-slanted derailers are not completely immune to bump forces tugging on the cable and resisting the return spring, but are very much better in this regard when using the smaller end of the freewheel where speeds tend to be highest.
I don't really see any difference between mtb and road derailers in terms of their slant angle, though there are obviously other changes to the cage, springs, etc which allow them to accomodate larger cogs. It's surprisingly subtle how the cage itself helps clear larger cogs on the mtb versions.
I believe it was Colnago dealers who had to strip Rino derailers off of bikes that had been shipped (to the US at least). I came across supplier of these previously-installed NOS derailers some years back, and who was helping to clear out old stuff from the bins at a big Colnago dealer in SoCal.
Campy did also have an Athena (and later Xenon) Synchro derailer with a slanted parallelogram, but with very little in the way of a drop-down knuckle (just merely an offset up top would be one way of looking at this). They apparently didn't want to appear "copycat", but soon relented as pressure mounted to achieve indexing perfection with the longer cables of integrated shifters. So this earlier slanted design never made it past when Ergolevers were fitted at these respective Athena and Xenon levels.
Slanted parallelograms have a problem though, which ultimately limits how much slant will still work with how much return-spring tension. Only a non-slanted parallelogram will eliminate any road impact vibration from trying to bounce the cage inward and outward (with only return-spring tension and the cable resisting this tendency). Note that traditional non-slanted derailers are not completely immune to bump forces tugging on the cable and resisting the return spring, but are very much better in this regard when using the smaller end of the freewheel where speeds tend to be highest.
I don't really see any difference between mtb and road derailers in terms of their slant angle, though there are obviously other changes to the cage, springs, etc which allow them to accomodate larger cogs. It's surprisingly subtle how the cage itself helps clear larger cogs on the mtb versions.
I believe it was Colnago dealers who had to strip Rino derailers off of bikes that had been shipped (to the US at least). I came across supplier of these previously-installed NOS derailers some years back, and who was helping to clear out old stuff from the bins at a big Colnago dealer in SoCal.
Last edited by dddd; 02-23-20 at 03:50 PM.
#17
Senior Member
Join Date: Nov 2004
Posts: 23,223
Mentioned: 654 Post(s)
Tagged: 1 Thread(s)
Quoted: 4722 Post(s)
Likes: 0
Liked 3,036 Times
in
1,874 Posts
Likes For T-Mar:
#18
Bianchi Goddess
Thread Starter
Join Date: Apr 2009
Location: Shady Pines Retirement Fort Wayne, In
Posts: 27,858
Bikes: Too many to list here check my signature.
Mentioned: 192 Post(s)
Tagged: 2 Thread(s)
Quoted: 2930 Post(s)
Liked 2,926 Times
in
1,491 Posts
I like the 'white' one
__________________
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
#19
Senior Member
I don't really see any difference between mtb and road derailers in terms of their slant angle, though there are obviously other changes to the cage, springs, etc which allow them to accomodate larger cogs. It's surprisingly subtle how the cage itself helps clear larger cogs on the mtb versions.
MTB rear derailleurs for 2x/3x setups have usually been intended for large cogs of somewhere from 28 to 36 teeth, but with very long cages and a lot of the drivetrain's range coming from the chainrings.
Meanwhile, the rear derailleurs that are aimed at 1x setups with enormous cassettes usually don't need steep parallelograms because they use a large offset between the jockey wheel and the pivot to manage chain gap. This doesn't create any problems if you have no front shifting, and arguably has the benefit of making the rear derailleur "adjust" itself for different cassettes.
SRAM has even made modern 1x-specific rear derailleurs with old-school-Shimano-esque dropped parallelograms.
To add some recent shenanigans into the mix...
It's always been interesting that nearly all modern derailleurs use both a sprung b-pivot and a slanted parallelogram. If the parallelogram roughly matches the slant of the cluster, and if the jockey wheel is placed concentric with the a-pivot, the derailleur should enjoy good chain gap and be almost totally unaffected by front shifts. It will also be mechanically simpler and, since you're not worried about how the derailleur's tensions balance against the b-pivot, you potentially have more freedom in selecting the spring for the a-pivot (and any damping, like with clutched derailleurs). Or, put another way, "why not do an indexed interpretation of a SunTour GT derailleur?"
Anyway, I was putting together a new gravel build, and I chose Shimano's RD-RX810 for the rear derailleur. It uses Shimano's 11-speed road cable pull, it has a lot of wrap, it's intended to be tolerant to wide front differences, and it's clutched to keep things well-behaved on the rough stuff, and all these things seemed to make it a good match for what I was doing. As I took it out of the box and inspected it, I realized that it had no b-pivot spring, and that the jockey wheel was concentric with the cage pulley. It turns out that a number Shimano's non-1x "shadow"-geometry derailleurs are like this!
#20
Senior Member
Join Date: Dec 2015
Location: San Diego
Posts: 703
Bikes: 1978 Bruce Gordon, 1977 Lippy, 199? Lippy tandem, Bike Friday NWT, 1982 Trek 720, 2012 Rivendell Atlantis, 1983 Bianchi Specialissima?
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 345 Post(s)
Liked 175 Times
in
107 Posts
#21
Senior Member
Join Date: Jan 2019
Posts: 528
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 237 Post(s)
Likes: 0
Liked 83 Times
in
64 Posts
It's always been interesting that nearly all modern derailleurs use both a sprung b-pivot and a slanted parallelogram. If the parallelogram roughly matches the slant of the cluster, and if the jockey wheel is placed concentric with the a-pivot, the derailleur should enjoy good chain gap and be almost totally unaffected by front shifts. It will also be mechanically simpler and, since you're not worried about how the derailleur's tensions balance against the b-pivot, you potentially have more freedom in selecting the spring for the a-pivot (and any damping, like with clutched derailleurs). Or, put another way, "why not do an indexed interpretation of a SunTour GT derailleur?"
Anyway, I was putting together a new gravel build, and I chose Shimano's RD-RX810 for the rear derailleur. It uses Shimano's 11-speed road cable pull, it has a lot of wrap, it's intended to be tolerant to wide front differences, and it's clutched to keep things well-behaved on the rough stuff, and all these things seemed to make it a good match for what I was doing. As I took it out of the box and inspected it, I realized that it had no b-pivot spring, and that the jockey wheel was concentric with the cage pulley. It turns out that a number Shimano's non-1x "shadow"-geometry derailleurs are like this!
Anyway, I was putting together a new gravel build, and I chose Shimano's RD-RX810 for the rear derailleur. It uses Shimano's 11-speed road cable pull, it has a lot of wrap, it's intended to be tolerant to wide front differences, and it's clutched to keep things well-behaved on the rough stuff, and all these things seemed to make it a good match for what I was doing. As I took it out of the box and inspected it, I realized that it had no b-pivot spring, and that the jockey wheel was concentric with the cage pulley. It turns out that a number Shimano's non-1x "shadow"-geometry derailleurs are like this!
#23
Senior Member
Join Date: Dec 2015
Location: San Diego
Posts: 703
Bikes: 1978 Bruce Gordon, 1977 Lippy, 199? Lippy tandem, Bike Friday NWT, 1982 Trek 720, 2012 Rivendell Atlantis, 1983 Bianchi Specialissima?
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 345 Post(s)
Liked 175 Times
in
107 Posts
#24
Senior Member
Join Date: Dec 2015
Location: San Diego
Posts: 703
Bikes: 1978 Bruce Gordon, 1977 Lippy, 199? Lippy tandem, Bike Friday NWT, 1982 Trek 720, 2012 Rivendell Atlantis, 1983 Bianchi Specialissima?
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 345 Post(s)
Liked 175 Times
in
107 Posts
#25
Bike Butcher of Portland
Join Date: Jul 2014
Location: Portland, OR
Posts: 11,639
Bikes: It's complicated.
Mentioned: 1299 Post(s)
Tagged: 0 Thread(s)
Quoted: 4682 Post(s)
Liked 5,800 Times
in
2,284 Posts
Dunno. I think the Huret Jubilee is #1 , followed by SunTour Cyclone first gen.
But looking at that Dura Ace, it's gotta be in the conversation.
But looking at that Dura Ace, it's gotta be in the conversation.
__________________
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.