WTF 😮

I would take it back. It is clearly broken.

Staggering isn't it? It's a wonder the poor old mech can shift.

Thats a point, how the hell does it shift if you're on one of the small flat bits?

Barels world champs dh bike to make up for his injured leg.

wait a minute, whats the advantage of this?

Biopace was a good idea.

Just 90 degrees out ending up in wheelspin/stall/wheelspin/stall.

Just speeds up the distruction of your knees

Fabien had a badly injured right knee which meant less power.The chainring is effectively smaller on the right powerstroke (rh peadal forward) giving a slightly easier gear for the right leg compared to the left on each full crank rotation.

It's to make it easier for zombies to cycle.

From their website-

Conclusion: the legs move faster the dead who are relatively less "dead"…

I'll have to get one for my single speed – I'm so old, I'm nearly dead, so I fit the target market.

I like BioPace – just shift the rings about until they feel right.

I thought biopace was ditched because it didn't offer much over standard kit, anyone know why it's making such a resurgence? I've seen it on a few pro road bikes this season.

Biopace was a good idea.
Just 90 degrees out ending up in wheelspin/stall/wheelspin/stall.

Not at all, common urban myth that…

From Sheldon Brown:
Biopace is a patented non-round chainwheel design made and licensed by Shimano. To a casual glance they resemble elliptical chainwheels, but on closer examination they turn out to be the exact 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.

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Those Osymetric ones are similar to the Rotor rings, elliptical chainrings are back in fashion.

Mostly marketing b.s?

crazy-legs.

I'm saying that from how it always felt to me when trying to ride with Biopace rings.
It kind of made me laugh that one year Biopace was the big thing.
Next year Semi Biopace* was the big thing.
The year after it was back to round…

*Almost round. 🙄

Luddites!!

of course the fact that circular chainrings are relatively easy and cheap to produce would have no bearing on the matter

my mate races and is sponsored by the rotor rings lot and said at first it was a bit weird and now it feels the normal. no faster tho lol

no faster tho

Bit like gears then Mick. 😉

aye stu 😉

It's more about efficiency and smoothness than speed. But on paper at least they do work. But you could argue they're just a fix for poor pedalling technique, which should be smooth and efficient anyway.

JoeNation – Member
…you could argue they're just a fix for poor pedalling technique, which should be smooth and efficient anyway.

Any pedalling technique I have is out the window after a couple of hours, so anything that helps a rider with a lousy technique has to be a benefit 🙂

But Bradley uses them. And Sastre. Must be shit.