Bicycle Mechanics - Biopace question for Sheldon (or anyone with answers)

Biopace chainrings are kind to this old man's knees, so I'm always on the lookout for them. I just aquired a crankset with a 130BCD 52/40. I always thought that 42t was the smallest 130BCD Biopace ring. So my questions are these:
1) Just what sizes DID Shimano make these in? In 130BCD I'm aware of 53, 52, 42, and 40T, in 110BCD 50, 48, 44, 40, 38, and 36T, in 74BCD 28 and 26T.
2) I'm not the only one beating the bushed for these things. What are the chances of Shimano (or an aftermarket producer like Vulta) doing a new production run?
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There are Rotor rings if you want a biopace effect.http://www.rotorcranksusa.com/s1-q-rings.shtml As far as biopace rings you can find some at older LBS's that might have some back stock.

I believe in the basement I have a 130 B.C. 39 tooth chain ring. Roger

There are Rotor rings if you want a biopace effect.http://www.rotorcranksusa.com/s1-q-rings.shtml As far as biopace rings you can find some at older LBS's that might have some back stock.The phasing of the wobble on the Q-rings are variable, so be sure to orient it so that the smallest-diameter is pulling on the chain when the crankarms are horizontal (max-force on downstroke) so that the motion is similar to Biopace. This lowers the load on the knees at that point (increases leg-velocity).

The other way of orienting these rings is the opposite with the chain being pulled by the largest-diameter portion of the ring when the cranks are horizontal. This will tend to slow down the leg on the downstroke and even out the uneven torque output (you can really hear the difference when riding on rollers). Bobby Julich sets his in this way.

Sugino, SR and Suntour also made oval rings back when Biopace was popular. But they never sold in the quantities that Shimano had.

Biopace chainrings are kind to this old man's knees, so I'm always on the lookout for them. I just aquired a crankset with a 130BCD 52/40. I always thought that 42t was the smallest 130BCD Biopace ring. So my questions are these:
1) Just what sizes DID Shimano make these in? In 130BCD I'm aware of 53, 52, 42, and 40T, in 110BCD 50, 48, 44, 40, 38, and 36T, in 74BCD 28 and 26T.

Those are the sizes I'm aware of for sure, but I think there may have been one short-lived model with steel rings that featured a 40-130 ring. I've never seen one of those rings as an aftermarket item though.

Sheldon "Biopace" Brown

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Those are the sizes I'm aware of for sure, but I think there may have been one short-lived model with steel rings that featured a 40-130 ring. I've never seen one of those rings as an aftermarket item though.

Sheldon "Biopace" Brown


Thanks for the answer; that confirms what I though.
The 130/40t ring is steel, and is on an Exage 300 crankset-not exactly high zoot.
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Here is a link on how to on make your own sprockets. E-mail the author from the link for obtaining elliptical patterns.
http://www.ihpva.org/Builders/Sprocket/
It would be relatively easy to have a machine shop manufacture a large number of elliptical chain rings on a CNC mill. Were talking about a production run of several hundred of each size to make production of these custom-made chain rings economically possible. Considering the small number of people that would be interested in purchasing a niche product such as this makes this almost impossible.

I just listed a 52 and 42 on Ebay if anyone is shopping for some.

Do the Biopace 'rings mount on standard spiders?

130 BCD. I had them on a sugino crankset for a while.

Do the Biopace 'rings mount on standard spiders?
Yup - they were all 130mm or 110mm bcd (and 74mm granny ring for triples with 110mm middle/outer rings). Standard spacing.

I do believe I have several sets of biopace rings in the ring drawer, I never realized they were worth anything I was just too cheap to throw them out . I have to see what I have.

Sugino made Cycloid rings for a while. Not sure exactly how they differed from Biopace.

I do believe I have several sets of biopace rings in the ring drawer, I never realized they were worth anything I was just too cheap to throw them out . I have to see what I have.
A good condition 48/38/28 BioPace crank set and BB typically sell for $200 or more on Ebay. It's a much sought after item for dedicated touring and long distance cyclists.

A good condition 48/38/28 BioPace crank set and BB typically sell for $200 or more on Ebay. It's a much sought after item for dedicated touring and long distance cyclists.

Sure they do; when attatched to the rest of a bike.:D
In the last year I've bought half a dozen Shimano crank/biopace ring sets on the 'bay, doubles and triples, and haven't paid over $25. NOS Deore or something like that might go for double or triple that, but no more.
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top506,
You might try to contact Gordy at this place. http://www.freewheelerbikeshop.com/
He usually has a rather extensive collection of older parts still in the box.