Absoulute Black- non round chain rings

[martinn]

Hi All,

OK oval chainrings are nothing new, this company seems to have a following in MTB circles and have branched out into road chain rings. They claim that they are different to how biopace worked, and that they seem to imply as a non professional you may get more benefit. although I am wary of how independent the independent research might actually be.

So has anyone tried these? To be honest I think I am quite safe as they don't cater for Campag, or at least I don't think they do.
Mug and money?

martin

[Brucey]

both Wiggins and Froome have won the TdeF whilst using oval chainrings which were oriented the 'normal' way round (as was common in the 1930s if not earlier) rather than the 'biopace' orientation. So you can safely conclude that they at least don't slow you down. I suspect however to get any benefit from them you may have to train/ride in a specific way.

cheers

[pwa]

Given the trouble some people have getting perfectly round rings to shift the chain about smoothly, adding the complication of teeth rising and falling within the front mech cage doesn't seem like the best idea in the world.

[Greystoke]

Shimano Biopace was around in the mid 80's. I'm sure I read somewhere that the high spot should've been 90 degrees from where Shimano had it....something to so with your knees?
Anyway it didn't catch on.

[MikeF]

Shimano Biopace was around in the mid 80's. I'm sure I read somewhere that the high spot should've been 90 degrees from where Shimano had it....something to so with your knees?
Anyway it didn't catch on.

The claim for Biopace was that the rings slowed down the rapid change of leg direction when pedals are at the top and bottom position. I quite like them. If the high spot is reversed the opposite effect occurs.

[bgnukem]

I got the impression Biopace were 90 degrees out of correct orientation, the smaller diameter should have been oriented at the TDC/BDC crank position to help rotation past the 'dead spots' and then the larger diameter (effectively higher gear) should have corresponded to the power position when the cranks were horizontal.

Is that correct?

What orientation did Highpath use with their Eggrings?

[foxyrider]

both Wiggins and Froome have won the TdeF whilst using oval chainrings which were oriented the 'normal' way round (as was common in the 1930s if not earlier) rather than the 'biopace' orientation. So you can safely conclude that they at least don't slow you down. I suspect however to get any benefit from them you may have to train/ride in a specific way.

cheers

Apparently when they did some power testing with the oval rings there was no discernable difference to round rings. Wiggo reverted to round, Froome has stuck with oval.

Having used Biopace in Shimano 'wrong' set up and in adjusted position my personal view was that it made my pedalling 'jerky', it was never as smooth as on round rings. I don't think this latest iteration are quite as oval so they may be smoother.

If there was an advantage the UCI would have banned them by now!

[MikeF]

I got the impression Biopace were 90 degrees out of correct orientation, the smaller diameter should have been oriented at the TDC/BDC crank position to help rotation past the 'dead spots' and then the larger diameter (effectively higher gear) should have corresponded to the power position when the cranks were horizontal.

Is that correct?

Not as I understand it. ^^

[cycle tramp]

I guess that oval chainrings found new popularity as part of the 'single chain ring' trabsmission - after all there was no front mech to worry about...
.... all of themanufacturers are repoting that there customers should be able to climb in a higher gear, with less gear changes and with less latic acid build up in the muscles over a longer ride.....
.....indepdent on line reviews seem to say the same thing, that the writer was dubious about fitting them (& expected to swap them back to round chain rings after the first ride) but that they generally felt that they were able to climb for longer in either the same or higher gear - although the overal performance of the oval chainring was not as high as the adverts suggested or equal to the cost of the oval chainring....
....most writers ended by saying they would kept their oval chain ring fitted to their bikes after testing, but when it wore out they would consider either an oval or round chainring on economic costs

[Greystoke]

https://www.sheldonbrown.com/biopace.html

seems Biopace hurt riders knees

[Graham]

https://www.sheldonbrown.com/biopace.html

seems Biopace hurt riders knees

Having read that page it would appear that Sheldon liked Biopace because they were easier on his knees and assisted his pedalling performance.

He comments that it was other non-round chainrings - with the alignment 90 degrees different to Biopace - that caused comments about knee problems from their users.

[MikeF]

https://www.sheldonbrown.com/biopace.html

seems Biopace hurt riders knees

Having read that page it would appear that Sheldon liked Biopace because they were easier on his knees and assisted his pedalling performance.

He comments that it was other non-round chainrings - with the alignment 90 degrees different to Biopace - that caused comments about knee problems from their users.

Indeed. It's obvious that he liked them.

[Greystoke]

I should read the whole article....

They've not really taken off though have they. I remember them when they were on touring bikes in the mid 80's and it seemed at the time everyone would have them.

[bgnukem]

Always seemed to me those rings would just exacerbate variations in rotational speed during pedalling, by slowing down the stroke at the dead spots (TDC and BDC), but Sheldon seemed to think this was better for the knees.

I guess perhaps a lesser degree of ovality would cause fewer problems with the front gear shift as the chain-to-front mech cage distance would not vary as much.

Never had chance to try Biopace myself and now Highpath Engineering have disappeared maybe Absolute Black is my chance?

If I could match them to some 180mm or 185mm cranks I'd be a happy bunny

[fossala]

I think oval rings (and short cranks) are a game changer for recumbents. I'm fine with them on uprights as well but wouldn't say I've noticed any benefit.