Oval chainrings

rockmonkeysc

Has anyone tried an oval chainring? Would you recommend one?

robertpb

I have them on my old 1986 custom rigid, you don't after a while notice that they are there.

A friend I used to ride with in the 80's owned Highpath Engineering and made ovals up to a few years ago, the Highpath website still has a lot of info on them. That's also where the oval rings for Chris Boardmans hour record were made.

Geoff Apps who I've ridden with over the past 30 years swears by them.

They are worth trying, you'll either love them or hate them, very marmite.

cooldad

I have mighty Biopace rings on a few bikes. Old ones obviously.

They are a bit rubbish.

robertpb

But then Biopace are a bit back to front.

JBA

I rode with Biopace chainrings in the 80's.
Had the cartilage removed from both knees in the 90's. I'm convinced those stupid chainrings were a contributory factor.

njee20

Indeed, but the modern ones are all the correct way around, so it's entirely irrelevant!

I've not tried one yet, a lot of friends are, and like them.

paul.skibum

I am interested too as I am looking at a 32T oval to replace my current 30T round one - the marketing spiel talks about improved traction under power and stuff.

dusk

I've got a 32t Absolute Black oval ring, in terms of the oval feeling I stopped noticing it after 5 minutes of riding. Did I feel it making more power? No idea, but I felt no adverse affect from it so it possibly has smoothed out my pedal stroke

cycleclinic

Oval chainrings have going in and out of fashion since the 1890's. No one has ever proved they make a difference. read bicycle science 3rd edition for a better description of the physics. If you think about it over one revolution of the crank the work done is the same so power is the same. Therefore you wont be any faster with them regardless of what the manufacturers claim about torque delivery at different points in the pedal stroke.

rockmonkeysc

The physics makes sense. It improves efficiency by reducing effort in the part of the stroke where your leg has the least strength and then increases as you get to the more efficient part of the stroke.
They seem to be very popular on r**d bikes where efficiency is everything.

The Rookie

I have Biopace on my Retro, its a 5 bolt so I rotated the rings round one bolt (72 degrees) which means they are pretty close now to where the modern ones have the largest radius (somewhere between 75 and 80 degrees ATDC seems usual), they certainly feel much better* to ride now than they did in what was patently the wrong place by any form of common sense, better than round rings is harder to say as they are the only rings I've had on this bike.

*They didn't feel wrong as such by themselves, just harder work than they do now or 'should' (subjectively) have felt.