South Salem Cycleworks Online
(503) 480-2001
email: sscycleworks@comcast.net
We have a huge stock of vintage and modern parts. Contact us!

SR & Sugino Elliptical chainrings in 74mm, 110mm & 130mm Bolt Circle Diameter (BCD)

On this page:
74mm BCD (Bolt Circle Diameter) Chainrings on this page:
SR (Sakae Ringyo): 28-tooth
Sugino: 28-tooth

110mm BCD (Bolt Circle Diameter) Chainrings on this page:
Sugino: 40-tooth
SR (Sakae Ringyo): 44-tooth

130mm BCD (Bolt Circle Diameter) Chainrings on this page:
SR (Sakae Ringyo): 42-tooth | 52-tooth

We also have a good stock of Shimano Biopace elliptical chainrings posted here.

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It is thought by a contributor to the Velobase.com site that both the SR and Sugino elliptical chainring productions were licensed by Shimano. So here's an explanaton of the Shimano elliptical chainrings, which also applies to the rings posted below.

Shimano Biopace chainrings brilliantly solve the problems that purely elliptical chain rings present. Sheldon Brown gave an excellent explanation of how Shimano's engineers have taken a flawed century-old idea to create a wonderfully designed and superbly efficient chainring.

"Biopace is a patented non-round chainwheel design made and licensed by Shimano. To a casual glance, Biopace chainwheels resemble elliptical chainwheels, but on closer examination they turn out to be the opposite of the classical elliptical design. The product of extensive research and computer-aided design, Biopace chainwheels have the small radius engaged when the cranks are horizontal, the large when they are vertical. This is because the Biopace design is based on a dynamic analysis of the motion and momentum of moving cranks and legs, unlike the static, geometric analysis that produced classical ellipticals.

"The theory is that during the power stroke, when the cranks are more or less horizontal, you are using the power of your legs to accelerate your feet, which get going quite fast in the lower gear provided for that part of the stroke. The momentum of your feet then carries the pedals through the "dead spot" when the cranks are near vertical. Since the rider doesn't push as hard during the power phase of the stroke, and motion is slower when the leg is changing direction, the Biopace design is gentler on the knees than even round chainwheels."

If you are unsure about what size chainring you need, Wolf Tooth Components has an excellent guide to measuring your rings.


74mm BCD (Bolt Circle Diameter) Chainrings:

SR OvalTech 28-tooth, 74mm BCD chainring. Used, $25.00

SR OvalTech chainring

Side one

SR Ovaltech chainrings

Side two

Sugino Cycloid 28-tooth, 74mm BCD chainring. Used

We have two: #1 | #2

Sugino Cycloid 28-tooth, 74mm BCD chainring #1. Used, $25.00

Sugino Cycloid chainring

Top side

Sugino Cycloid chainring

And the back side of the same ring

Sugino Cycloid 28-tooth, 74mm BCD chainring #2. Used, $25.00

Sugino Cycloid chainring

Many hills left in this ring

Sugino Cycloid chainrings

And here it is turned over.


110mm BCD (Bolt Circle Diameter) Chainrings:

Sugino Cycloid 40-tooth, 110mm BCD chainring. Used, $25.00

Sugino Cycloid chainring

Top view

Sufin Cycloid chainring

And the same ring flipped over

SR OvalTech 110mm BCD 44-tooth chainring

We have two: New | Used

SR OvalTech 110mm BCD 44-tooth chainring. New, $25.00

This was removed from a new bike

SR Ovaltech 44-tooth ring

Side one

SR Ovaltech chainring

And side two

SR OvalTech 110mm BCD 44-tooth chainring. Used, $25.00

SR Ovaltech chainring

In great condition

SR Ovaltech chainring

And just as good flipped over.


130mm BCD (Bolt Circle Diameter) Chainrings:

SR OvalTech 130mm BCD 42-tooth chainring. Used

We have two: #1 | #2

SR OvalTech 130mm BCD 42-tooth chainring #1. Used, $25.00

SR Ovaltech chainwing

Side one

SR Ovaltech chainring

And side two

SR OvalTech 130mm BCD 42-tooth chainring #2. Used, $25.00

SR Ovaltech chainring

Used, but with lots of miles left in it.

SR OvalTech chainring

And here's the other side.

SR OvalTech 130mm BCD 52-tooth chainring. Used, $25.00

We have two: #1 | #2

SR OvalTech 130mm BCD 52-tooth chainring #1. Used, $25.00

SR Ovaltech chainring

Lovely condition

SR Ovaltech chainring

And here's the flip side

SR OvalTech 130mm BCD 52-tooth chainring #2. Used, $25.00

SR Ovaltech 52-tooth ring

Nice looking ring.

SR Ovaltech chainring

Side two