SpeedofLite 

RCMoeur 

"As Collopy voiced this complaint, he was probably thinking about the large box cluttering up his parts room, slowly filling with Biopace chainrings removed from the bikes of riders who do." Replicated on a smaller scale around the world by C&V bike-fixers.

John E

My Schwinn came with BioPace rings, which were the first things I go rid of when I adapted the gearing to my own needs.

Roger M

I found that biopace chainrings work well..





As a rack mounting interface.

randyjawa 

I am not much of a Bio-Pace fan. In my mind, the look funny and don't do much to improve my performance or pleasure when out and about. This monster crank ring was a nightmare to ride. At about thirty rpm, the bike actually started to feel like it was bouncing...

abdon 

Who needs biospace when you can have a reflex bike!



"Designed to turn bumps and frame shake into kinetic energy, the Alter Reflex redefines traditional suspension bikes. The patented design uses a specially shaped top tube and flexible curved down-tube to allow the frame to flex vertically, absorb road bumps, and make pedaling easier. The frame is constructed from aircraft-grade aluminum for a lightweight, flexible feel, while the curved down-tube is made of spring steel. Specific tubular flexibility—from #1 being most flexible, to #6 being most stiff—allows you to choose the tube that suits your needs."

So the flexible aluminum top tube (WTF?) allows you to store downstroke energy so it removes the pedaling dead spot? Have I been so out of touch with the modern stuff that I missed when they came out with flexible aluminum?

Chris_Wrigh

I have a Biopace on a steel frame (approx 1990). The eccentricity of the ring is very subtle (maybe +2% at widest to -2% at narrowest). Personally I can't tell the difference between it and a normal (circular) chainring. So put me in the 'indifferent' category. I also have a bike (same era) with a Sugino Cycloid ring. That one is more of a regular oval, oriented so that the gear is increased in the middle of the leg's downstroke (so, quite different from Biopace). I haven't had much time on the bike so far, but I think I prefer it to Biopace.

georges1

I had biopace lx cranks on my merida mountainbike in 2015 changed for them for xt 780t hollow tech II cranks back in 2016

georges1

I wonder if the frame isn't prone to breaking. Wonder what grade of aircraft aluminium is used for the frame , is it Alcoa CU 92 6013 aluminium series, that is a good question

Trakhak

It's a shame that Shimano went all in in Biopace, essentially strong-arming the bike companies by saying that if they wanted a Shimano-equipped bike, it was going to have Biopace rings. Turned out some people liked them, some didn't. It should have been offered as an after-market choice instead, like different handlebar bends, crank arm lengths, etc.

pastorbobnlnh 

I've been meaning to post to this thread and mention two things:

I've been hunting for a 50T or 51T Biopace outer ring (130BCD) and any inner Biopace road rings (42T, 43T, 44T, etc.). I'd be glad to take such clutter off the hands of any Biopace non-aficionados.

PM me if I can help to unburden your parts bin.

top506

Rev, AFAIK 50t and 44t Biopace were only made in 110 BCD. 130 outers were restricted to 52 and 53t.

Top

pastorbobnlnh 

DANG! No wonder I haven't had any success locating any. It's curious that Shimano didn't offer a broader tooth count range.

Top, thanks for the info.

Jeff Neese

I've replaced Biopace the few times I've bought a bike with them. Then my Trek Elance 400T came with Sakae Oval Tech, and I wanted to complete the build with as little expense and also keep it as original as possible. I don't notice a big difference and I sort of forget they're there, unless I look down at the cranks while pedaling. It looks funny and I sometimes do a double-take until I remember.

Jeff Neese

You mean a manufacturer introduced a product with no real benefit to the user, simply in order to promote the idea of "New and Improved" and to sell more product to gullible consumers? No, that would never happen in the bicycle world.

tcs

"...in my opinion, they are of real value for the vast majority of non-racing cyclists." - Sheldon Brown

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

tcs

"50T, 48T, 46T, 44T, 38T and 36T chainrings were made in the 110mm bolt circle diameter; 28T and 26T chainwheels in the 74mm bolt circle diameter. These chainrings were generally used in triple cranksets: the 74mm bolt circle is only used for the innermost chainring of a triple. However, the outer chainring may be left off or replaced with a chainguard/protector plate (like a toothless chainwheel) for a wide-step double.

"Sizes 53, 52T, 42T and 40T (that one only in steel) were made in the 130mm bolt circle and were generally used in racing doubles, though some cranksets have a 130mm outer and 74mm inner bolt circle. Few front derailers could handle a 52T outer and 28T inner Biopace chainwheel, though." - Sheldon Brown

top506

Very early on in my BF career I exchanged several emails with Sheldon concerning the care and feeding of Biopace. Mostly he shared his experience with different index positions and tips on setting up the FD. Thanks to his guidance I've built up half a dozen or so bikes with Biopace triple cranks that index perfectly with Shimano and Microshift brifters. It ain't easy, and component selection is critical, but it can be done.
I've often shared my opinion that Biopace makes climbing easier for old guys with bum knees.

Top

tcs

The whole "reduce force exerted" is good for old guys who don't want the knees to become vagrant, too.

Ach! My ex-wife and daughter in an '84 testimonial:

pastorbobnlnh 

I was hoping to regear my 53T 130BCD 600 cranks. I have a 52T but have found I prefer a 50T and can compromise with a 51T. I might have to go round.

tcs

Aftermarket product packaging

top506

You know, there IS a 600 110 BCD triple, right?

Top

Doug Fattic 

My opinion (that doesn't have any foundation so this is just a guess) is that the problem with Biopace chainrings is that they don't work well with the fast crowd riding in groups because the uneven teeth pattern breaks cup the faster pedaling rhythm necessary to deal with fast accelerations when cornering for example that is necessary to stay on wheels. Their negative opinion effected sales. I doubt Shimano research and testing showed no benefit. For those that ride at a slower steady pace, some may still prefer them.

Jeff Wills

I’m pretty sure they don’t exist, Shimano only built a couple sizes of Biopace and Biopace II.

If you’re interested, I bet Euro-Asia Imports still has boxes of them. When I worked there (35 years ago) we customized cranksets by removing Biopace rings and installing round SR rings. Euro-Asia never throws anything away…

pastorbobnlnh 

Top, what's a triple? Is that what Northern New Englanders drink in order to survive winter? Possibly sometime around the end of February until mid-March?

Now that I've forsaken the hills and mountains of NH for the flatlands of coastal GA, I rarely use my small ring. Thus, the reason for finding a 50T. I need a stiff head wind to run a 42T.

However, you do make a valid point. If I can find a 110BCD Tri-Color 600 in the same condition, I can run it as a double, which I'd probably do at 50T and 44T.