A few posts ago, I mentioned the Shimano Dura-Ace aerodynamic (EX and, later, AX) components of the early 1980s. While the components themselves didn't catch on quite as much as Shimano hoped, they had (and still have) their devotees. More to the point, they have their influence on today's components and bikes.
Perhaps no part of the EX system better epitomized the ensemble's inability to catch on with the cycling public and its long-term impact than the Dyna-Drive pedals.
The Dura Ace EX Dyna-Drive (DD) crank was actually a lovely piece of work and would look as appropriate on a current bike as one of the era, or even an earlier time. It resembled other Dura Ace cranks made since, more or less. Its spider and pedal arm have a finish and shape like those of its successors, save for the flare near the end of the crank arm. There was a reason for that: the pedal mounting hole was about double the diameter of that on any other crank.
That oversized pedal hole was made to accommodate the DD pedal, which had eliminated the through-axle found in most pedal bodies in favor of something shaped more like a plumbing joint that mounted outboard of the pedal. The bearings were inside of it. In contrast, most pedals have a set of bearings inside each end of the body.
In addition to lighter weight (about a third less than Campagnolo and other quill-caged road pedals of the time), this setup, because of the size of its mounting, was supposed to be stiffer. I never used the pedals or crank myself, but I knew a couple of cyclists who did and wouldn't use anything else.
The mounting system also resulted in a pedal platform that was lower than, rather than level with, the center of the mounting hole in the crank arm. As a result, at the bottom of the pedal stroke, the bottom of the foot was lower than the pedaling axis. This was supposed to offer better biodynamics in the pedal stroke, which would lead to a more even power transfer throughout the rotation of the pedal.
To me, it sounds like the benefit the Biopace (slightly elliptical) chainrings Shimano would make around the same time. As I mentioned in an earlier post, I never used Biopace for any length of time, so I can't say whether or not they actually offered the claimed benefit. Likewise for the DD pedals, which I never used. I will say, however, that the few cyclists I knew who used them liked them very much.
Shimano made adapters so that conventional pedals could be used with DD cranks, or so that DD pedals could be used with conventional cranks. I don't know anyone who used those, but I saw some cyclists ride conventional Dura Ace cranks and the pedals of their choice with the other aerodynamic EX parts.
Eventually, the 600 racing series and the then-new Deore touring and mountain bike parts would also offer the Dyna Drive option. They were even less popular in those ensembles than in Dura Ace. It makes sense, especially for the touring ensemble: If your DD pedal hit a curb or got snagged on a rock or tree root in the middle of nowhere, you probably wouldn't find a replacement--or even an adapter--in the local farm machinery shop where bike repairs are done.
Still, those pedals have had a lasting influence: Look and other contemporary pedals, while they don't completely eliminate the through-axle, use a shorter axle than on earlier pedals. More important, though, they use one set of oversized bearings on the side of the pedal that mounts to the crank, eliminating the bearing on the outer part of the pedal. This makes lighter, more streamlined pedals possible.
And, of course, the shapes of many of today's pedals owe much to the aerodynamic design of DD pedals, which in turn were influenced by the Lyotard No. 23, a.k.a. Marcel Berthet, platform pedal.
Perhaps no part of the EX system better epitomized the ensemble's inability to catch on with the cycling public and its long-term impact than the Dyna-Drive pedals.
The Dura Ace EX Dyna-Drive (DD) crank was actually a lovely piece of work and would look as appropriate on a current bike as one of the era, or even an earlier time. It resembled other Dura Ace cranks made since, more or less. Its spider and pedal arm have a finish and shape like those of its successors, save for the flare near the end of the crank arm. There was a reason for that: the pedal mounting hole was about double the diameter of that on any other crank.
That oversized pedal hole was made to accommodate the DD pedal, which had eliminated the through-axle found in most pedal bodies in favor of something shaped more like a plumbing joint that mounted outboard of the pedal. The bearings were inside of it. In contrast, most pedals have a set of bearings inside each end of the body.
In addition to lighter weight (about a third less than Campagnolo and other quill-caged road pedals of the time), this setup, because of the size of its mounting, was supposed to be stiffer. I never used the pedals or crank myself, but I knew a couple of cyclists who did and wouldn't use anything else.
The mounting system also resulted in a pedal platform that was lower than, rather than level with, the center of the mounting hole in the crank arm. As a result, at the bottom of the pedal stroke, the bottom of the foot was lower than the pedaling axis. This was supposed to offer better biodynamics in the pedal stroke, which would lead to a more even power transfer throughout the rotation of the pedal.
To me, it sounds like the benefit the Biopace (slightly elliptical) chainrings Shimano would make around the same time. As I mentioned in an earlier post, I never used Biopace for any length of time, so I can't say whether or not they actually offered the claimed benefit. Likewise for the DD pedals, which I never used. I will say, however, that the few cyclists I knew who used them liked them very much.
Shimano made adapters so that conventional pedals could be used with DD cranks, or so that DD pedals could be used with conventional cranks. I don't know anyone who used those, but I saw some cyclists ride conventional Dura Ace cranks and the pedals of their choice with the other aerodynamic EX parts.
Eventually, the 600 racing series and the then-new Deore touring and mountain bike parts would also offer the Dyna Drive option. They were even less popular in those ensembles than in Dura Ace. It makes sense, especially for the touring ensemble: If your DD pedal hit a curb or got snagged on a rock or tree root in the middle of nowhere, you probably wouldn't find a replacement--or even an adapter--in the local farm machinery shop where bike repairs are done.
Still, those pedals have had a lasting influence: Look and other contemporary pedals, while they don't completely eliminate the through-axle, use a shorter axle than on earlier pedals. More important, though, they use one set of oversized bearings on the side of the pedal that mounts to the crank, eliminating the bearing on the outer part of the pedal. This makes lighter, more streamlined pedals possible.
And, of course, the shapes of many of today's pedals owe much to the aerodynamic design of DD pedals, which in turn were influenced by the Lyotard No. 23, a.k.a. Marcel Berthet, platform pedal.
