Classic & Vintage - Shimano Biopace and other "non-round Chainrings"

I ran across this (http://www.noncircularchainring.be/pdf/Biomechanical%20study%20chainrings%20-%20release%202.pdf) on the interwebs while looking into the Q-rings. This is, as far as I can tell, the only scientific study on the subject of non-round chainrings.

I searched the forum for "Biopace", but it returned a bunch of threads that only refereed to it in passing, and I could not find one that was just for elliptical chainrings. If there is one, let me know, and I will move the link there.

What are your experiences with biopace and other elliptical chainrings? Do you love them? Hate them? Want to try them? Any shifting problems?



http://www.noncircularchainring.be/pdf/Biomechanical%20study%20chainrings%20-%20release%202.pdf

None of the above but I did notice that most riders in the time trial and track events in the London Olympics seemed to be using elliptical rings...

Biopace, a very subjective topic. "Bad for knees, knees not effected, not good for high cadence, doesn't effect cadence" etc. I used to ride them in the 80s, don't remember any issues with them, probably changed them because they went out of style. I do have some biopace rings, I may install them and see what I think now, I'm guessing for the riding I do it won't make a difference. If you have some give them a try and see how they ride for you. Lots of 80s mtb were spec'ed with them and they are easy and cheap to find. I guess some folks think they look dorky and change them for that reason, but probably not as many C&Vers are concerned with the dorkiness factor as other segments of the cycling community. Oh yeah, the biopace rings need to be mounted in a specific relationship to the cranks, but I can't recall off the top of my head what it is. If you get/try some let us know what you think.

Brian

I've had them both, and jumped back and forth from a bike with and a bike without the Biopace rings. I could tell very little, if any difference. At my performance level(low) I don't think it really matters.

wow so biopace IS really worse than circular.. by 0.2% lol

Frantik, I know, I was surprised to find that none are really that much better than round.

I have some Biopace on a diamondback topanga that I am in the process of building. I can not wait to try it out, but was interested to find this paper on the matter.

I have several different Biopace rings (all steel so I haven't used them) and some SR Sakae Oval Tech rings that also haven't gone on a bike. I'm working on a Peugeot hybrid right now and am planning on doing a radical 48-28 set up with some alloy Stronglight BioStrong rings. I pulled these out of a box at the LBS at no charge and have been waiting for something to put them on. The middle ring was unfortunately missing which is why I'm going to try it with what I have. Just riding it on the road in the very eliptical small ring I don't notice much of a difference.

270025

None of the above but I did notice that most riders in the time trial and track events in the London Olympics seemed to be using elliptical rings...

I noticed that as well. Maybe there is something to it, even if it is just placebo effect.

Frantik, I know, I was surprised to find that none are really that much better than round.

I have some Biopace on a diamondback topanga that I am in the process of building. I can not wait to try it out, but was interested to find this paper on the matter.

It's funny that biopace is the only one that is worse. I wish they had data on the other makes of biopace and had tried to find an "optimal" position. I was contemplating experimenting with putting a biopace ring on a pedicab to see if it would save my knees at all, but now I definitely will NOT be doing that :-p

I threw a set onto my Bianchi FOR the dorkiness factor. :p

http://s36.photobucket.com/albums/e26/sstulken80/Bianchi/biopace.jpg

The idea behind Biopace (as I understand it) was to ease stress on your knees, which means putting the "large" portion of the ring 90 degrees out of phase from where it would help deliver more leverage, since momentum needs to be considered. I haven't noticed a huge difference either way -- the main thing for me is to remember to spin small gears rather than to mash big ones. ;)

It's funny that biopace is the only one that is worse. I wish they had data on the other makes of biopace and had tried to find an "optimal" position. I was contemplating experimenting with putting a biopace ring on a pedicab to see if it would save my knees at all, but now I definitely will NOT be doing that :-p

From what I understand, you can rotate the biopace ring one mounting point forward (I still do not know which way that is) and it will put it closer to "optimal" position. At that point, it should, theoretically, be about +.05%

The idea behind Biopace (as I understand it) was to ease stress on your knees, which means putting the "large" portion of the ring 90 degrees out of phase from where it would help deliver more leverage, since momentum needs to be considered. I haven't noticed a huge difference either way -- the main thing for me is to remember to spin small gears rather than to mash big ones. ;)

That is indeed what the idea behind biopace was. Seems logical to me? As for dorkiness factor, I think it is great :-)

I run Biopace and love em'.

http://i1024.photobucket.com/albums/y303/echo2011/misc/Biopace.jpg

I have some Biopace on a diamondback topanga that I am in the process of building. I can not wait to try it out, but was interested to find this paper on the matter.
I've got them on a Topanga, a Sorrento and 2 Ascent EXs. Can't really tell any difference between them and regular rings.

I've never seen that study, thanks for pointing it out jonainmi! If I could offer one minor criticism to Messrs Malfait et al, it would be the commonly heard refrain in the C&V forum: "do your musculoskeletal modeling from the drive side please!" :)

I have a pair of biopace rings on a Nishiki Modulus (stock set). In the 52, you can't really tell that it's not round, but switching from that to a cannondale with a round 52, you can tell a difference in pedaling. The little ring (42? I think) is also biopace, and on that one you can really feel the changes in cadence as you go around the ring - especially at faster RPM (which for me is 110 or so).

I also have a Nishiki touring bike that was pre-biopace. It has a round 52 ring, but the other two rings are elliptical (I want to say they're 36 and 46). Those are just weird - you spin super fast going down in the pedal stroke, but then kinda laze along on the top. It gives the illusion that you're spinning faster than you really are; however, you really do get some nice pulling power with the 36 - more than expected with the gears you're given.

I've never seen that study, thanks for pointing it out jonainmi! If I could offer one minor criticism to Messrs Malfait et al, it would be the commonly heard refrain in the C&V forum: "do your musculoskeletal modeling from the drive side please!" :)

You are welcome. This is the first time I have seen it as well, but it appears to be older...

From what I can gather, there seems to not be much of a difference between non-round rings, and round rings.

For low cadence, say 60 rpm or less (like slogging up hill, Biopace or Rotor work ) but not so much that I need them. For spinning, no.

couldn't tell the difference either. FYI, I have a set of biopace chainrings from an old Trek if anyone wants .... can't do anything with 'em. Local to NYC can have 'em free.

I ran BioPace triple for a while and really didn't notice much difference once I got used to pedaling it. The granny was most noticeably different and I didn't care much for the out-of-round cranking on it, but the middle and tall rings were fine.

I have Biopace on my 1988 Cannondale, I really can't tell the difference


http://i549.photobucket.com/albums/ii384/sportridertex/IMAG0034.jpg

I rode BioPace when they first came out, and felt the benefits right off; I could feel a difference in my knees, and my spin felt smoother.

Almost 30 years later, and after having surgery on BOTH of my knees (both ACL's, right MCL and meniscus) I put a set of them back on my
commuting bike. This time the benefits were more obvious... no joint discomfort at all while spinning, and much less noise from my knee joints!
My cool down is also less painful after a long ride.

I was sold on them back in the 80's, and now I have them on all of my bikes. If they're in good condition I'll take them off anyone's hands!

(74/110 BCD only, 26/36/46 preferred but if you have 28/44/50 I'll take those, too)!

:thumb:

I rode BioPace when they first came out, and felt the benefits right off; I could feel a difference in my knees, and my spin felt smoother.

Almost 30 years later, and after having surgery on BOTH of my knees (both ACL's, right MCL and meniscus) I put a set of them back on my
commuting bike. This time the benefits were more obvious... no joint discomfort at all while spinning, and much less noise from my knee joints!
My cool down is also less painful after a long ride.

I was sold on them back in the 80's, and now I have them on all of my bikes. If they're in good condition I'll take them off anyone's hands!

(74/110 BCD only, 26/36/46 preferred but if you have 28/44/50 I'll take those, too!

:thumb:

from what i gathered, the study suggested that they should actually be harder on your knees.. but if they work for you, they work! :)

jonainmi, A very interesting read, thanks!

The article plainly points out the advantages and disadvantages of each design tested. It also allowed me to more fully understand why some cyclists rotated the the Biopace chain rings to the cyclist's positive effect. I was a little surprised at how close a Biopace chain ring compares with a circular chain ring. I can now see why the oval chain rings are becoming popular (again?) in road racing, or primarily time trialing, but I think those designs put alot of load on the joints; a case of give and take I suppose.

Brad

the thing that seems strangest to me is that almost all of the rings saw improvement by rotating them away from the recommended angles from their creators. i would assume the people designing these things would have found the ideal angle in their R&D phase

Alan and anyone else looking for biopace; I have several new or like-new biopace rings I'd gladly trade for round rings (e.g. 52/130, 49/130, or 49/110):
- 52/130 plated steel
- 46/110 grey anodized aluminum Biopace II (this one is NOS)
- 42/130 plated steel (I think I have it somewhere; not sure)

My '86 Super Sport came with Biopace rings. I have around 300 miles on them so far, and find they feel a little different, in a good way.
No downside that I can tell.

Discussed on this link as well:
www.bikeforums.net/showthread.php/606294-Shimano-Biopace-mix-and-match?p=14492471&highlight=#post14492471 (http://www.bikeforums.net/showthread.php/606294-Shimano-Biopace-mix-and-match?p=14492471&highlight=#post14492471)

Also discussed on this thread:

www.bikeforums.net/showthread.php/606294-Shimano-Biopace-mix-and-match?p=14492471&highlight=#post14492471 (http://www.bikeforums.net/showthread.php/606294-Shimano-Biopace-mix-and-match?p=14492471&highlight=#post14492471)

I used Biopace on several bikes back in the early '90s, and found that I could sell them for enough money to buy a better crankset. Other than that I see them as gimmicks that just makeup for and encourage poor pedaling form.

from what i gathered, the study suggested that they should actually be harder on your knees.. but if they work for you, they work! :)
The study only says that the Biopace rings are not as efficient as a round ring, not worse on the joints.


the thing that seems strangest to me is that almost all of the rings saw improvement by rotating them away from the recommended angles from their creators. i would assume the people designing these things would have found the ideal angle in their R&D phase
I noticed that too, and was wondering if the designers were just using the ideas in their heads, or were drinking, or what?


I used Biopace on several bikes back in the early '90s, and found that I could sell them for enough money to buy a better crankset. Other than that I see them as gimmicks that just makeup for and encourage poor pedaling form.
I am not sure how it could cause poor pedaling form? your foot still goes in a circle...

the thing that seems strangest to me is that almost all of the rings saw improvement by rotating them away from the recommended angles from their creators. i would assume the people designing these things would have found the ideal angle in their R&D phase

Well, there are two possibilities -- either the designers had no idea what they were doing, or the Belgian mechanical engineers/mathematicians doing this study are missing something. ;)

....I am not sure how it could cause poor pedaling form? your foot still goes in a circle...

I think Biopace "trains" or promotes you to pedal in squares rather than in true circles.

I think Biopace "trains" or promotes you to pedal in squares rather than in true circles.

Never experienced that on any of the Biopace-equipped bikes I have had.

Sheldon likes it!

http://sheldonbrown.com/biopace.html

I use the original biopace that came on the 105 cranks on my commuter. To prevent sweating I don't spin on this bike and feel like biopace works really well for this slower cadence application. They definitely feel weird for sprinting. Tried it a few times during races and just couldn't get used to it.

I had read that on sheldon's website a little while ago, and found it interesting. I have yet to finish the build up of the diamond back, but from what I have heard here I can not wait to get it done!

I really really want to know what it feels like to pedal in "squares"

I used biopace on a previous bike; I liked it but not enough to put effort into using it in the future.

I've got bikes with Biopace ('89 Trek 950), Suntour/SR's version of it ('89 Fuji Saratoga), and without (newer bikes). I ride the Fuji and a later Cannondale MTB the most so I frequently switch back and forth. Some days I'll go from one right to the other. I can't say I've ever noticed a difference in knee pain or speed/efficiency.

I have heard from a lot of cyclist around here that BioPace is nothing special, they didn't even know they were riding it for the longest time. Most didn't think there was a difference in knee pain/painlessness.

An LBS owner I know here says they are the best thing since sliced bread.

I have the DiamondBack mostly done now, and I have a few different cranksets for it. I am going to try switching them out and doing a comparison on them. But, I am going to take the researchers at their word. :-)

My opinion on thses have changed.....I wore out a set of rings on a 80's Giant Iguana that was converted to HD Road chores. They were ok I thought, the lower ring was very eliptical and was only worthwhile for climbing over rocks or deep mud on my occassional detours off road. I switched it out last week for a Road triple and HOLY COW, the bike is so smooth now. Switching from bike to bike, I never noticed the difference, just thought the Iguana was a pig and lived with it. Oh how I was so wrong! There is a noticable difference if you spin, mashers might not notice but for spinning I think (my opinion) the Bio-pace rings are less than worthless on a road bike.

For low cadence, say 60 rpm or less (like slogging up hill, Biopace or Rotor work ) but not so much that I need them. For spinning, no.

Bingo. BioPace is for climbing. Standing on the pedals, heart pounding in my ears, sweat dripping off my brow, putting major grunt into that hill that's trying to kill me, the BioPace rings seem to vault me forward on that awesome downstroke. So, basically, I owe them my life.

Or it could just be my imagination. At any rate, the 80's-looking yellow sticker is pretty groovy. And the nerd factor is pretty high.

I appreciate the BioPace on my Mt. Bike for climbing in the saddle and anything with a steady cadence, but standing on the pedals....absolutely not.

Back in the mid to late 70's somebody developed a drive system that used a cam to do the same thing. The idea was that you could use an effectively lower gear to "spin" on the down stroke, and maximize rest across the top. The chainring was round and moved forward and backward in relation to the crank. Scott Dickson, who has placed in the leading group at Paris-Brest-Paris was helping to promote the setup. Strange to watch from behind.

The BioPace chainring was reversed engineered to give the same stroke with a machined chainwheel. IIRC, there was a patent lawsuit. But this is being recalled from the depths of a very cluttered mind.

I had a Bridgestone mountain bike with biopace. Didn't make much of a difference.

edit: After some web sluething, I found that the inventor was Larry Brown and the device was called a PowerCam. Manufactured by houdille industries in Ft. Worth of Texas. Dates seem to be more mid 80's

There is a noticable difference if you spin, mashers might not notice but for spinning I think (my opinion) the Bio-pace rings are less than worthless on a road bike.

Yeah I noticed it almost immediately when I would spin at high RPMs.. for mashers it's cool though

btw for biopace fans, i've two sets of nice alloy rings, one set for mtbs, one for road cranks.. PM me if interested..

I have ridden lots of round rings and ellipitical rings and can't tell the difference. It is possible, though it might be my imagination, that the ellipitical rings are easier on my knees. However...

The rings on this old Motobecane were a bloody nightmare to ride. At a cadence of twenty rpm+, the bike started to actually feel like it was hopping...

307512 307513 307514

^ Is it April 1st already?


randyjawa at speed :speedy:

Nice one, 'gnome! :roflmao2:

+1 frantik. So what other oversights were committed?