Equipment/Product Review (1977) The IPD Drive System
#1
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Equipment/Product Review (1977) The IPD Drive System

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WTB: Slingshot bicycle promotional documents (catalog, pamphlets, etc).
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WTB: Slingshot bicycle promotional documents (catalog, pamphlets, etc).
WTB: American Cycling May, Jul, Aug, Oct, 1966.
WTB: Bicycle Guide issues 1984 (any); Dec 1985; Apr 1994; May, Jun 1996; May 1997.
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WTB: Bike World issue Jun 1974.
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#5
Exactly. It was different from the Alenax in that the Biocam's crank motion was still circular while the Alenax's lever drive was nearly vertical. The "advantage" was that gearing was nearly infinitely variable from low ratio to high. The ad copy claimed "50 speeds" which I guess means there were 50 distinct ratios in the drive mechanism.
Here's the ads:
BioCam, home
BioCam ad copy
Here's the ads:
BioCam, home
BioCam ad copy
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Jeff Wills
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Jeff Wills
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#6
So many intriguing attempts to improve the bicycle drivetrain!
Considering that so many are just trying to vary the effective gear as a function of the pedal position, I wonder why some folks chose to use complex mechanisms like this when they could just use a oval (or nearly oval) chainring such as BioPace.
Granted, the IPD drive does also offer variable gearing, which is valuable, but at a considerable increase in complexity.
I can't help but wonder where the funding for this sort of project comes from. Is research and prototyping all funded by the inventor, in hopes of attracting funding for further development, or maybe hopes of selling it to an existing bike component manufacturer?
Steve in Peoria
Considering that so many are just trying to vary the effective gear as a function of the pedal position, I wonder why some folks chose to use complex mechanisms like this when they could just use a oval (or nearly oval) chainring such as BioPace.
Granted, the IPD drive does also offer variable gearing, which is valuable, but at a considerable increase in complexity.
I can't help but wonder where the funding for this sort of project comes from. Is research and prototyping all funded by the inventor, in hopes of attracting funding for further development, or maybe hopes of selling it to an existing bike component manufacturer?
Steve in Peoria
#7
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The fundamental misunderstanding of most if not all of these ideas is that somehow if one could only get the rider to apply more muscular power to the bicycle drive-train you'd get better results.
Which ignores the fact that in most cases[1] the limit to performance is not muscular power but aerobic, and at sustained submaximal effort - which suggest strongly that efficiency (which for this discussion includes weight and reliability) is a better goal. As demonstrated by the market penetration of such creations.
[1] track sprint cycling excepted, but I suspect that even here regulations as well as practical considerations would yield the same conclusion.
Which ignores the fact that in most cases[1] the limit to performance is not muscular power but aerobic, and at sustained submaximal effort - which suggest strongly that efficiency (which for this discussion includes weight and reliability) is a better goal. As demonstrated by the market penetration of such creations.
[1] track sprint cycling excepted, but I suspect that even here regulations as well as practical considerations would yield the same conclusion.
#8
The fundamental misunderstanding of most if not all of these ideas is that somehow if one could only get the rider to apply more muscular power to the bicycle drive-train you'd get better results.
Which ignores the fact that in most cases[1] the limit to performance is not muscular power but aerobic, and at sustained submaximal effort - which suggest strongly that efficiency (which for this discussion includes weight and reliability) is a better goal. As demonstrated by the market penetration of such creations.
[1] track sprint cycling excepted, but I suspect that even here regulations as well as practical considerations would yield the same conclusion.
Which ignores the fact that in most cases[1] the limit to performance is not muscular power but aerobic, and at sustained submaximal effort - which suggest strongly that efficiency (which for this discussion includes weight and reliability) is a better goal. As demonstrated by the market penetration of such creations.
[1] track sprint cycling excepted, but I suspect that even here regulations as well as practical considerations would yield the same conclusion.
In the case of Biopace chainrings, I think Shimano was looking at the big picture of overall performance, at least based on the reports of fully instrumented riders that were part of their testing (not that I could dig up the articles that mention this). In contrast, I have the feeling that some of these other innovations came from engineers and machinists who had ideas of improving specific issues such as optimizing mechanical advantage without any consideration for the bigger issues. Personally, I fully understand the allure of tweaking some aspect of technology and solving problems. It's easy to ignore the need to create a design that solves the bigger issues, since it requires understanding that there might be a bigger issue! Even if the inventor does understand the bigger issue, there is then the problem of creating a team of experts in the other areas of knowledge related to the bigger issue, and that's just not any fun for the inventor.
I say this as a retired engineer with experience in development of products that required a team of mechanical engineers, electrical engineers, manufacturing engineers, test engineers, system engineers, and management to lead the team. This means meetings, planning, budgets, schedules, and all of those other things that are a pain, but are essential to success.
To be fair, I should probably include the marketing folks as members of the team, since someone needs to understand what the customer wants and what they will spend on the product. Engineering hasn't always had a favorable opinion of marketing, but they do serve a purpose, even if the Dilbert cartoons can suggest otherwise.....

Steve in Peoria







