Classic Shimano BioPace outer chainring from the early 90s Exage 500LX, 400LX and 300LX chainsets with 48 teeth. BioPace was designed to offer the rider a more effective pedal stroke, it was reasonably short lived but came back with a vengeance in the mid 2000s when the bike industry had run out of new things to invent. The oval chainrings supposedly put more power into the top part of the pedal stroke thus making you faster and/or making it easier.
- Shimano Exage 500/400/300 LX cranks:
- 48 tooth
- For 3/32″ chains
- 110 BCD
- BioPace SG oval ‘technology’
- From the 1991 model range
- Made in Japan