shimano biopace crank

[galactico]

evening all

i have just treated myself to a lovely retro racing bike. i was giving it a good inspection when i got it home and noticed it has oval chainrings marked biopace. i have not come across this before and wondered if anyone can let me know how they work and differ from a regular set up and are they any good?

cheers

paul

 

[corshamjim]

There's a wikipedia article on them: http://en.wikipedia.org/wiki/Biopace

I think it's probably about right.

I had a Claud Butler tourer in the '90s with Biopace chainrings. To be honest I can't say it made any difference one way or the other but I'm no expert.

 

[Alessandro Petacchi]

It was a naff idea!

 

[Norm]

It's a good idea badly marketed and derided by racing types because it allowed a lower cadence which some mistook for an excuse for snobbery.

Although, tbh, I'd listen to Sheldon before I listened to anyone on a forum.

 

[Brommyboy]

I rode up Hardknot Pass using a biopace ring in the early 90's, and could not wait to change it for a circular ring! The uneven stroke became very difficult to use when under intense power going up the 1:3 hill. I used to describe this ride as a doddle - one long rest interrupted by short bursts of cycling.

 

[zizou]

The Rotor Q rings have tweaked the idea (the 'large' part is in a different part of the pedal stroke) and seem to be gaining quite a bit of popularity in the pro peloton. Would quite like to try it out but it is still pretty expensive just now

 

[Dan B]

I had biopace in the 90s too. Other than making it more difficult to adjust the front mech for clean shifting, I can't say it made much difference that wasn't accountable to placebo/nocebo

 

[Ravenbait]

I didn't get on with the biopace I had. YMMV.

Sam

 

[Raa]

I had a good experience with bio-pace on a recent tour form the UK to Switzerland and back, AFAIAC it is a good system, although I like round chainrings too!

Definitely stick with them for at least 2 weeks before deciding to change; they feel odd at first but you quickly adapt a technique to suit.

 

[Holdsworth]

I used to have a Biopace crankset on my '92 Holdsworth, that was before the dodgy LBS stripped the pedal thread! I didn't pay much attention to how they felt as they went round although there were variations in the resistance as I pedaled around in the smaller wheel, it felt a little odd going up hills and I can't say it gave me much of an advantage.