john hawrylak

I like the biopace chain rings, but they are no longer made, however are available on e-bay.

Is it possible to instal the 130 mm BCD Biopace rings on a new 10 speed crank, like a 105?. Get the best of both world, biopace and crnak with outboard bearings.

If so, can a 9 speed chain be used with the biopace rings if a 9 speed cassette is used

John Hawrylak
Woodstown NJ

thirdgenbird

as long as the bcd is the same they will mount up fine. shifting may be your only concern. i cant comment about shimano, but campagnolo changed the chainring spacing to improve shifting with the narrower chain. this was done by milling the mounting tabs on the outer ring. that said, with 9spd you should be fine.

biopace may not be available any more but you can get ovalized rings from rotor. i would look at this route as well.

Ridefreemc

Change the subject slightly, but I had big trouble with Biopace rings. If you plan on spinning a lot (that is high cadence) you may put strain on the knee on the forward part of the stroke. If you are a masher you may be fine. On the down stroke the pedal has more leverage, but across the top it has less - right when you knee is at a vulnerable point.

FastJake

+1

Shifting may suffer compared to the new rings with pins and rivets, but as long as you're ok with that go for it. I think your idea of running 9S chain and a 9S rear is a good idea, rather than trying 10S.

3alarmer 

PM me on what you are looking for. I was looking through
the chainring collection at the Bike Kitchen today while
working my shift and IIRC there were several in pretty good
condition.

You want the chainrings, they can use some cash.

ultraman6970

+1 on this one. Thas the main reason the racing community did not like them (the majority), as for regular human beings makes no difference, their cadence is too slow to even notice it.

simonaway427

Just buy some Q rings and be done with it.

HillRider

Sure, at a minimum of $45 each, most of their chainrings at $150 -$175 each and a double road set at $265 for chainrings only, that's obviously the way to go.

fietsbob

The Shimano new 105 and above, given 3D shape for added stiffness ./. so outer ring is not flat,
but there are other 130 bcd cranks, and the era was using 7 ~ 8 speed chain

Friction shifting?
STI may not work as well when the radius in the chainring is
changing. and lift pins and taller teeth and there is no fine tuning while you ride,
more like, 3 big 'ka-thunks'

Bar end shifters are so much better in that situation, I would think.

simonaway427

i didn't see any budget constraints in the OP's post - so what's the issue? BTW, my ring was $100 a piece at PBK (50T).